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If only Patch Tuesdays came around infrequently — like total solar eclipse rare — instead of just creeping up on us each month like The Man in the Moon. Although to be fair, it would be tough for Microsoft to eclipse the number of vulnerabilities fixed in this month’s patch batch — a record 147 flaws in Windows and related software.
Yes, you read that right. Microsoft today released updates to address 147 security holes in Windows, Office, Azure, .NET Framework, Visual Studio, SQL Server, DNS Server, Windows Defender, Bitlocker, and Windows Secure Boot.
“This is the largest release from Microsoft this year and the largest since at least 2017,” said Dustin Childs, from Trend Micro’s Zero Day Initiative (ZDI). “As far as I can tell, it’s the largest Patch Tuesday release from Microsoft of all time.”
Tempering the sheer volume of this month’s patches is the middling severity of many of the bugs. Only three of April’s vulnerabilities earned Microsoft’s most-dire “critical” rating, meaning they can be abused by malware or malcontents to take remote control over unpatched systems with no help from users.
Most of the flaws that Microsoft deems “more likely to be exploited” this month are marked as “important,” which usually involve bugs that require a bit more user interaction (social engineering) but which nevertheless can result in system security bypass, compromise, and the theft of critical assets.
Ben McCarthy, lead cyber security engineer at Immersive Labs called attention to CVE-2024-20670, an Outlook for Windows spoofing vulnerability described as being easy to exploit. It involves convincing a user to click on a malicious link in an email, which can then steal the user’s password hash and authenticate as the user in another Microsoft service.
Another interesting bug McCarthy pointed to is CVE-2024-29063, which involves hard-coded credentials in Azure’s search backend infrastructure that could be gleaned by taking advantage of Azure AI search.
“This along with many other AI attacks in recent news shows a potential new attack surface that we are just learning how to mitigate against,” McCarthy said. “Microsoft has updated their backend and notified any customers who have been affected by the credential leakage.”
CVE-2024-29988 is a weakness that allows attackers to bypass Windows SmartScreen, a technology Microsoft designed to provide additional protections for end users against phishing and malware attacks. Childs said one of ZDI’s researchers found this vulnerability being exploited in the wild, although Microsoft doesn’t currently list CVE-2024-29988 as being exploited.
“I would treat this as in the wild until Microsoft clarifies,” Childs said. “The bug itself acts much like CVE-2024-21412 – a [zero-day threat from February] that bypassed the Mark of the Web feature and allows malware to execute on a target system. Threat actors are sending exploits in a zipped file to evade EDR/NDR detection and then using this bug (and others) to bypass Mark of the Web.”
Update, 7:46 p.m. ET: A previous version of this story said there were no zero-day vulnerabilities fixed this month. BleepingComputer reports that Microsoft has since confirmed that there are actually two zero-days. One is the flaw Childs just mentioned (CVE-2024-21412), and the other is CVE-2024-26234, described as a “proxy driver spoofing” weakness.
Satnam Narang at Tenable notes that this month’s release includes fixes for two dozen flaws in Windows Secure Boot, the majority of which are considered “Exploitation Less Likely” according to Microsoft.
“However, the last time Microsoft patched a flaw in Windows Secure Boot in May 2023 had a notable impact as it was exploited in the wild and linked to the BlackLotus UEFI bootkit, which was sold on dark web forums for $5,000,” Narang said. “BlackLotus can bypass functionality called secure boot, which is designed to block malware from being able to load when booting up. While none of these Secure Boot vulnerabilities addressed this month were exploited in the wild, they serve as a reminder that flaws in Secure Boot persist, and we could see more malicious activity related to Secure Boot in the future.”
For links to individual security advisories indexed by severity, check out ZDI’s blog and the Patch Tuesday post from the SANS Internet Storm Center. Please consider backing up your data or your drive before updating, and drop a note in the comments here if you experience any issues applying these fixes.
Adobe today released nine patches tackling at least two dozen vulnerabilities in a range of software products, including Adobe After Effects, Photoshop, Commerce, InDesign, Experience Manager, Media Encoder, Bridge, Illustrator, and Adobe Animate.
KrebsOnSecurity needs to correct the record on a point mentioned at the end of March’s “Fat Patch Tuesday” post, which looked at new AI capabilities built into Adobe Acrobat that are turned on by default. Adobe has since clarified that its apps won’t use AI to auto-scan your documents, as the original language in its FAQ suggested.
“In practice, no document scanning or analysis occurs unless a user actively engages with the AI features by agreeing to the terms, opening a document, and selecting the AI Assistant or generative summary buttons for that specific document,” Adobe said earlier this month.
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Apple and Microsoft recently released software updates to fix dozens of security holes in their operating systems. Microsoft today patched at least 60 vulnerabilities in its Windows OS. Meanwhile, Apple’s new macOS Sonoma addresses at least 68 security weaknesses, and its latest update for iOS fixes two zero-day flaws.
Last week, Apple pushed out an urgent software update to its flagship iOS platform, warning that there were at least two zero-day exploits for vulnerabilities being used in the wild (CVE-2024-23225 and CVE-2024-23296). The security updates are available in iOS 17.4, iPadOS 17.4, and iOS 16.7.6.
Apple’s macOS Sonoma 14.4 Security Update addresses dozens of security issues. Jason Kitka, chief information security officer at Automox, said the vulnerabilities patched in this update often stem from memory safety issues, a concern that has led to a broader industry conversation about the adoption of memory-safe programming languages [full disclosure: Automox is an advertiser on this site].
On Feb. 26, 2024, the Biden administration issued a report that calls for greater adoption of memory-safe programming languages. On Mar. 4, 2024, Google published Secure by Design, which lays out the company’s perspective on memory safety risks.
Mercifully, there do not appear to be any zero-day threats hounding Windows users this month (at least not yet). Satnam Narang, senior staff research engineer at Tenable, notes that of the 60 CVEs in this month’s Patch Tuesday release, only six are considered “more likely to be exploited” according to Microsoft.
Those more likely to be exploited bugs are mostly “elevation of privilege vulnerabilities” including CVE-2024-26182 (Windows Kernel), CVE-2024-26170 (Windows Composite Image File System (CimFS), CVE-2024-21437 (Windows Graphics Component), and CVE-2024-21433 (Windows Print Spooler).
Narang highlighted CVE-2024-21390 as a particularly interesting vulnerability in this month’s Patch Tuesday release, which is an elevation of privilege flaw in Microsoft Authenticator, the software giant’s app for multi-factor authentication. Narang said a prerequisite for an attacker to exploit this flaw is to already have a presence on the device either through malware or a malicious application.
“If a victim has closed and re-opened the Microsoft Authenticator app, an attacker could obtain multi-factor authentication codes and modify or delete accounts from the app,” Narang said. “Having access to a target device is bad enough as they can monitor keystrokes, steal data and redirect users to phishing websites, but if the goal is to remain stealth, they could maintain this access and steal multi-factor authentication codes in order to login to sensitive accounts, steal data or hijack the accounts altogether by changing passwords and replacing the multi-factor authentication device, effectively locking the user out of their accounts.”
CVE-2024-21334 earned a CVSS (danger) score of 9.8 (10 is the worst), and it concerns a weakness in Open Management Infrastructure (OMI), a Linux-based cloud infrastructure in Microsoft Azure. Microsoft says attackers could connect to OMI instances over the Internet without authentication, and then send specially crafted data packets to gain remote code execution on the host device.
CVE-2024-21435 is a CVSS 8.8 vulnerability in Windows OLE, which acts as a kind of backbone for a great deal of communication between applications that people use every day on Windows, said Ben McCarthy, lead cybersecurity engineer at Immersive Labs.
“With this vulnerability, there is an exploit that allows remote code execution, the attacker needs to trick a user into opening a document, this document will exploit the OLE engine to download a malicious DLL to gain code execution on the system,” Breen explained. “The attack complexity has been described as low meaning there is less of a barrier to entry for attackers.”
A full list of the vulnerabilities addressed by Microsoft this month is available at the SANS Internet Storm Center, which breaks down the updates by severity and urgency.
Finally, Adobe today issued security updates that fix dozens of security holes in a wide range of products, including Adobe Experience Manager, Adobe Premiere Pro, ColdFusion 2023 and 2021, Adobe Bridge, Lightroom, and Adobe Animate. Adobe said it is not aware of active exploitation against any of the flaws.
By the way, Adobe recently enrolled all of its Acrobat users into a “new generative AI feature” that scans the contents of your PDFs so that its new “AI Assistant” can “understand your questions and provide responses based on the content of your PDF file.” Adobe provides instructions on how to disable the AI features and opt out here.
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Microsoft Corp. today pushed software updates to plug more than 70 security holes in its Windows operating systems and related products, including two zero-day vulnerabilities that are already being exploited in active attacks.
Top of the heap on this Fat Patch Tuesday is CVE-2024-21412, a “security feature bypass” in the way Windows handles Internet Shortcut Files that Microsoft says is being targeted in active exploits. Redmond’s advisory for this bug says an attacker would need to convince or trick a user into opening a malicious shortcut file.
Researchers at Trend Micro have tied the ongoing exploitation of CVE-2024-21412 to an advanced persistent threat group dubbed “Water Hydra,” which they say has being using the vulnerability to execute a malicious Microsoft Installer File (.msi) that in turn unloads a remote access trojan (RAT) onto infected Windows systems.
The other zero-day flaw is CVE-2024-21351, another security feature bypass — this one in the built-in Windows SmartScreen component that tries to screen out potentially malicious files downloaded from the Web. Kevin Breen at Immersive Labs says it’s important to note that this vulnerability alone is not enough for an attacker to compromise a user’s workstation, and instead would likely be used in conjunction with something like a spear phishing attack that delivers a malicious file.
Satnam Narang, senior staff research engineer at Tenable, said this is the fifth vulnerability in Windows SmartScreen patched since 2022 and all five have been exploited in the wild as zero-days. They include CVE-2022-44698 in December 2022, CVE-2023-24880 in March 2023, CVE-2023-32049 in July 2023 and CVE-2023-36025 in November 2023.
Narang called special attention to CVE-2024-21410, an “elevation of privilege” bug in Microsoft Exchange Server that Microsoft says is likely to be exploited by attackers. Attacks on this flaw would lead to the disclosure of NTLM hashes, which could be leveraged as part of an NTLM relay or “pass the hash” attack, which lets an attacker masquerade as a legitimate user without ever having to log in.
“We know that flaws that can disclose sensitive information like NTLM hashes are very valuable to attackers,” Narang said. “A Russian-based threat actor leveraged a similar vulnerability to carry out attacks – CVE-2023-23397 is an Elevation of Privilege vulnerability in Microsoft Outlook patched in March 2023.”
Microsoft notes that prior to its Exchange Server 2019 Cumulative Update 14 (CU14), a security feature called Extended Protection for Authentication (EPA), which provides NTLM credential relay protections, was not enabled by default.
“Going forward, CU14 enables this by default on Exchange servers, which is why it is important to upgrade,” Narang said.
Rapid7’s lead software engineer Adam Barnett highlighted CVE-2024-21413, a critical remote code execution bug in Microsoft Office that could be exploited just by viewing a specially-crafted message in the Outlook Preview pane.
“Microsoft Office typically shields users from a variety of attacks by opening files with Mark of the Web in Protected View, which means Office will render the document without fetching potentially malicious external resources,” Barnett said. “CVE-2024-21413 is a critical RCE vulnerability in Office which allows an attacker to cause a file to open in editing mode as though the user had agreed to trust the file.”
Barnett stressed that administrators responsible for Office 2016 installations who apply patches outside of Microsoft Update should note the advisory lists no fewer than five separate patches which must be installed to achieve remediation of CVE-2024-21413; individual update knowledge base (KB) articles further note that partially-patched Office installations will be blocked from starting until the correct combination of patches has been installed.
It’s a good idea for Windows end-users to stay current with security updates from Microsoft, which can quickly pile up otherwise. That doesn’t mean you have to install them on Patch Tuesday. Indeed, waiting a day or three before updating is a sane response, given that sometimes updates go awry and usually within a few days Microsoft has fixed any issues with its patches. It’s also smart to back up your data and/or image your Windows drive before applying new updates.
For a more detailed breakdown of the individual flaws addressed by Microsoft today, check out the SANS Internet Storm Center’s list. For those admins responsible for maintaining larger Windows environments, it often pays to keep an eye on Askwoody.com, which frequently points out when specific Microsoft updates are creating problems for a number of users.
The final Patch Tuesday of 2023 is upon us, with Microsoft Corp. today releasing fixes for a relatively small number of security holes in its Windows operating systems and other software. Even more unusual, there are no known “zero-day” threats targeting any of the vulnerabilities in December’s patch batch. Still, four of the updates pushed out today address “critical” vulnerabilities that Microsoft says can be exploited by malware or malcontents to seize complete control over a vulnerable Windows device with little or no help from users.
Among the critical bugs quashed this month is CVE-2023-35628, a weakness present in Windows 10 and later versions, as well as Microsoft Server 2008 and later. Kevin Breen, senior director of threat research at Immersive Labs, said the flaw affects MSHTML, a core component of Windows that is used to render browser-based content. Breen notes that MSHTML also can be found in a number of Microsoft applications, including Office, Outlook, Skype and Teams.
“In the worst-case scenario, Microsoft suggests that simply receiving an email would be enough to trigger the vulnerability and give an attacker code execution on the target machine without any user interaction like opening or interacting with the contents,” Breen said.
Another critical flaw that probably deserves priority patching is CVE-2023-35641, a remote code execution weakness in a built-in Windows feature called the Internet Connection Sharing (ICS) service that lets multiple devices share an Internet connection. While CVE-2023-35641 earned a high vulnerability severity score (a CVSS rating of 8.8), the threat from this flaw may be limited somewhat because an attacker would need to be on the same network as the target. Also, while ICS is present in all versions of Windows since Windows 7, it is not on by default (although some applications may turn it on).
Satnam Narang, senior staff research engineer at Tenable, notes that a number of the non-critical patches released today were identified by Microsoft as “more likely to be exploited.” For example, CVE-2023-35636, which Microsoft says is an information disclosure vulnerability in Outlook. An attacker could exploit this flaw by convincing a potential victim to open a specially crafted file delivered via email or hosted on a malicious website.
Narang said what makes this one stand out is that exploitation of this flaw would lead to the disclosure of NTLM hashes, which could be leveraged as part of an NTLM relay or “pass the hash” attack, which lets an attacker masquerade as a legitimate user without ever having to log in.
”It is reminiscent of CVE-2023-23397, an elevation of privilege vulnerability in Microsoft Outlook that was exploited in the wild as a zero day and patched in the March 2023 Patch Tuesday release,” Narang said. “However, unlike CVE-2023-23397, CVE-2023-35636 is not exploitable via Microsoft’s Preview Pane, which lowers the severity of this flaw.”
As usual, the SANS Internet Storm Center has a good roundup on all of the patches released today and indexed by severity. Windows users, please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any difficulties as a result of these patches.
Microsoft today released updates to fix more than five dozen security holes in its Windows operating systems and related software, including three “zero day” vulnerabilities that Microsoft warns are already being exploited in active attacks.
The zero-day threats targeting Microsoft this month include CVE-2023-36025, a weakness that allows malicious content to bypass the Windows SmartScreen Security feature. SmartScreen is a built-in Windows component that tries to detect and block malicious websites and files. Microsoft’s security advisory for this flaw says attackers could exploit it by getting a Windows user to click on a booby-trapped link to a shortcut file.
Kevin Breen, senior director of threat research at Immersive Labs, said emails with .url attachments or logs with processes spawning from .url files “should be a high priority for threat hunters given the active exploitation of this vulnerability in the wild.”
The second zero day this month is CVE-2023-36033, which is a vulnerability in the “DWM Core Library” in Microsoft Windows that was exploited in the wild as a zero day and publicly disclosed prior to patches being available. It affects Microsoft Windows 10 and later, as well as Microsoft Windows Server 2019 and subsequent versions.
“This vulnerability can be exploited locally, with low complexity and without needing high-level privileges or user interaction,” said Mike Walters, president and co-founder of the security firm Action1. “Attackers exploiting this flaw could gain SYSTEM privileges, making it an efficient method for escalating privileges, especially after initial access through methods like phishing.”
The final zero day in this month’s Patch Tuesday is a problem in the “Windows Cloud Files Mini Filter Driver” tracked as CVE-2023-36036 that affects Windows 10 and later, as well as Windows Server 2008 at later. Microsoft says it is relatively straightforward for attackers to exploit CVE-2023-36036 as a way to elevate their privileges on a compromised PC.
Beyond the zero day flaws, Breen said organizations running Microsoft Exchange Server should prioritize several new Exchange patches, including CVE-2023-36439, which is a bug that would allow attackers to install malicious software on an Exchange server. This weakness technically requires the attacker to be authenticated to the target’s local network, but Breen notes that a pair of phished Exchange credentials will provide that access nicely.
“This is typically achieved through social engineering attacks with spear phishing to gain initial access to a host before searching for other vulnerable internal targets – just because your Exchange Server doesn’t have internet-facing authentication doesn’t mean it’s protected,” Breen said.
Breen said this vulnerability goes hand in hand with three other Exchange bugs that Microsoft designated as “exploitation more likely:” CVE-2023-36050, CVE-2023-36039 and CVE-2023-36035.
Finally, the SANS Internet Storm Center points to two additional bugs patched by Microsoft this month that aren’t yet showing signs of active exploitation but that were made public prior to today and thus deserve prioritization. Those include: CVE-2023-36038, a denial of service vulnerability in ASP.NET Core, with a CVSS score of 8.2; and CVE-2023-36413: A Microsoft Office security feature bypass. Exploiting this vulnerability will bypass the protected mode when opening a file received via the web.
Windows users, please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any difficulties as a result of these patches.
Microsoft today issued security updates for more than 100 newly-discovered vulnerabilities in its Windows operating system and related software, including four flaws that are already being exploited. In addition, Apple recently released emergency updates to quash a pair of zero-day bugs in iOS.
Apple last week shipped emergency updates in iOS 17.0.3 and iPadOS 17.0.3 in response to active attacks. The patch fixes CVE-2023-42724, which attackers have been using in targeted attacks to elevate their access on a local device.
Apple said it also patched CVE-2023-5217, which is not listed as a zero-day bug. However, as Bleeping Computer pointed out, this flaw is caused by a weakness in the open-source “libvpx” video codec library, which was previously patched as a zero-day flaw by Google in the Chrome browser and by Microsoft in Edge, Teams, and Skype products. For anyone keeping count, this is the 17th zero-day flaw that Apple has patched so far this year.
Fortunately, the zero-days affecting Microsoft customers this month are somewhat less severe than usual, with the exception of CVE-2023-44487. This weakness is not specific to Windows but instead exists within the HTTP/2 protocol used by the World Wide Web: Attackers have figured out how to use a feature of HTTP/2 to massively increase the size of distributed denial-of-service (DDoS) attacks, and these monster attacks reportedly have been going on for several weeks now.
Amazon, Cloudflare and Google all released advisories today about how they’re addressing CVE-2023-44487 in their cloud environments. Google’s Damian Menscher wrote on Twitter/X that the exploit — dubbed a “rapid reset attack” — works by sending a request and then immediately cancelling it (a feature of HTTP/2). “This lets attackers skip waiting for responses, resulting in a more efficient attack,” Menscher explained.
Natalie Silva, lead security engineer at Immersive Labs, said this flaw’s impact to enterprise customers could be significant, and lead to prolonged downtime.
“It is crucial for organizations to apply the latest patches and updates from their web server vendors to mitigate this vulnerability and protect against such attacks,” Silva said. In this month’s Patch Tuesday release by Microsoft, they have released both an update to this vulnerability, as well as a temporary workaround should you not be able to patch immediately.”
Microsoft also patched zero-day bugs in Skype for Business (CVE-2023-41763) and Wordpad (CVE-2023-36563). The latter vulnerability could expose NTLM hashes, which are used for authentication in Windows environments.
“It may or may not be a coincidence that Microsoft announced last month that WordPad is no longer being updated, and will be removed in a future version of Windows, although no specific timeline has yet been given,” said Adam Barnett, lead software engineer at Rapid7. “Unsurprisingly, Microsoft recommends Word as a replacement for WordPad.”
Other notable bugs addressed by Microsoft include CVE-2023-35349, a remote code execution weakness in the Message Queuing (MSMQ) service, a technology that allows applications across multiple servers or hosts to communicate with each other. This vulnerability has earned a CVSS severity score of 9.8 (10 is the worst possible). Happily, the MSMQ service is not enabled by default in Windows, although Immersive Labs notes that Microsoft Exchange Server can enable this service during installation.
Speaking of Exchange, Microsoft also patched CVE-2023-36778, a vulnerability in all current versions of Exchange Server that could allow attackers to run code of their choosing. Rapid7’s Barnett said successful exploitation requires that the attacker be on the same network as the Exchange Server host, and use valid credentials for an Exchange user in a PowerShell session.
For a more detailed breakdown on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any difficulties as a result of these patches.
Microsoft today issued software updates to fix at least five dozen security holes in Windows and supported software, including patches for two zero-day vulnerabilities that are already being exploited. Also, Adobe, Google Chrome and Apple iOS users may have their own zero-day patching to do.
On Sept. 7, researchers at Citizen Lab warned they were seeing active exploitation of a “zero-click,” zero-day flaw to install spyware on iOS devices without any interaction from the victim.
“The exploit chain was capable of compromising iPhones running the latest version of iOS (16.6) without any interaction from the victim,” the researchers wrote.
According to Citizen Lab, the exploit uses malicious images sent via iMessage, an embedded component of Apple’s iOS that has been the source of previous zero-click flaws in iPhones and iPads.
Apple says the iOS flaw (CVE-2023-41064) does not seem to work against devices that have its ultra-paranoid “Lockdown Mode” enabled. This feature restricts non-essential iOS features to reduce the device’s overall attack surface, and it was designed for users concerned that they may be subject to targeted attacks. Citizen Lab says the bug it discovered was being exploited to install spyware made by the Israeli cyber surveillance company NSO Group.
This vulnerability is fixed in iOS 16.6.1 and iPadOS 16.6.1. To turn on Lockdown Mode in iOS 16, go to Settings, then Privacy and Security, then Lockdown Mode.
Not to be left out of the zero-day fun, Google acknowledged on Sept. 11 that an exploit for a heap overflow bug in Chrome is being exploited in the wild. Google says it is releasing updates to fix the flaw, and that restarting Chrome is the way to apply any pending updates. Interestingly, Google says this bug was reported by Apple and Citizen Lab.
On the Microsoft front, a zero-day in Microsoft Word is among the more concerning bugs fixed today. Tracked as CVE-2023-36761, it is flagged as an “information disclosure” vulnerability. But that description hardly grasps at the sensitivity of the information potentially exposed here.
Tom Bowyer, manager of product security at Automox, said exploiting this vulnerability could lead to the disclosure of Net-NTLMv2 hashes, which are used for authentication in Windows environments.
“If a malicious actor gains access to these hashes, they can potentially impersonate the user, gaining unauthorized access to sensitive data and systems,” Bowyer said, noting that CVE-2023-36761 can be exploited just by viewing a malicious document in the Windows preview pane. “They could also conduct pass-the-hash attacks, where the attacker uses the hashed version of a password to authenticate themselves without needing to decrypt it.”
The other Windows zero-day fixed this month is CVE-2023-36802. This is an “elevation of privilege” flaw in the “Microsoft Streaming Service Proxy,” which is built into Windows 10, 11 and Windows Server versions. Microsoft says an attacker who successfully exploits the bug can gain SYSTEM level privileges on a Windows computer.
Five of the flaws Microsoft fixed this month earned its “critical” rating, which the software giant reserves for vulnerabilities that can be exploited by malware or malcontents with little or no interaction by Windows users.
According to the SANS Internet Storm Center, the most serious critical bug in September’s Patch Tuesday is CVE-2023-38148, which is a weakness in the Internet Connection Sharing service on Windows. Microsoft says an unauthenticated attacker could leverage the flaw to install malware just sending a specially crafted data packet to a vulnerable Windows system.
Finally, Adobe has released critical security updates for its Adobe Reader and Acrobat software that also fixes a zero-day vulnerability (CVE-2023-26369). More details are at Adobe’s advisory.
For a more granular breakdown of the Windows updates pushed out today, check out Microsoft Patch Tuesday by Morphus Labs. In the meantime, consider backing up your data before updating Windows, and keep an eye on AskWoody.com for reports of any widespread problems with any of the updates released as part of September’s Patch Tuesday.
Update: Mozilla also has fixed zero-day flaw in Firefox and Thunderbird, and the Brave browser was updated as well. It appears the common theme here is any software that uses a code library called “libwebp,” and that this vulnerability is being tracked as CVE-2023-4863.
“This includes Electron-based applications, for example – Signal,” writes StackDiary.com. “Electron patched the vulnerability yesterday. Also, software like Honeyview (from Bandisoft) released an update to fix the issue. CVE-2023-4863 was falsely marked as Chrome-only by Mitre and other organizations that track CVE’s and 100% of media reported this issue as “Chrome only”, when it’s not.”
Microsoft Corp. today issued software updates to plug more than 70 security holes in its Windows operating systems and related products, including multiple zero-day vulnerabilities currently being exploited in the wild.
Six of the flaws fixed today earned Microsoft’s “critical” rating, meaning malware or miscreants could use them to install software on a vulnerable Windows system without any help from users.
Last month, Microsoft acknowledged a series of zero-day vulnerabilities in a variety of Microsoft products that were discovered and exploited in-the-wild attacks. They were assigned a single placeholder designation of CVE-2023-36884.
Satnam Narang, senior staff research engineer at Tenable, said the August patch batch addresses CVE-2023-36884, which involves bypassing the Windows Search Security feature.
“Microsoft also released ADV230003, a defense-in-depth update designed to stop the attack chain associated that leads to the exploitation of this CVE,” Narang said. “Given that this has already been successfully exploited in the wild as a zero-day, organizations should prioritize patching this vulnerability and applying the defense-in-depth update as soon as possible.”
Redmond patched another flaw that is already seeing active attacks — CVE-2023-38180 — a weakness in .NET and Visual Studio that leads to a denial-of-service condition on vulnerable servers.
“Although the attacker would need to be on the same network as the target system, this vulnerability does not require the attacker to have acquired user privileges,” on the target system, wrote Nikolas Cemerikic, cyber security engineer at Immersive Labs.
Narang said the software giant also patched six vulnerabilities in Microsoft Exchange Server, including CVE-2023-21709, an elevation of privilege flaw that was assigned a CVSSv3 (threat) score of 9.8 out of a possible 10, even though Microsoft rates it as an important flaw, not critical.
“An unauthenticated attacker could exploit this vulnerability by conducting a brute-force attack against valid user accounts,” Narang said. “Despite the high rating, the belief is that brute-force attacks won’t be successful against accounts with strong passwords. However, if weak passwords are in use, this would make brute-force attempts more successful. The remaining five vulnerabilities range from a spoofing flaw and multiple remote code execution bugs, though the most severe of the bunch also require credentials for a valid account.”
Experts at security firm Automox called attention to CVE-2023-36910, a remote code execution bug in the Microsoft Message Queuing service that can be exploited remotely and without privileges to execute code on vulnerable Windows 10, 11 and Server 2008-2022 systems. Microsoft says it considers this vulnerability “less likely” to be exploited, and Automox says while the message queuing service is not enabled by default in Windows and is less common today, any device with it enabled is at critical risk.
Separately, Adobe has issued a critical security update for Acrobat and Reader that resolves at least 30 security vulnerabilities in those products. Adobe said it is not aware of any exploits in the wild targeting these flaws. The company also issued security updates for Adobe Commerce and Adobe Dimension.
If you experience glitches or problems installing any of these patches this month, please consider leaving a comment about it below; there’s a fair chance other readers have experienced the same and may chime in here with useful tips.
Additional reading:
-SANS Internet Storm Center listing of each Microsoft vulnerability patched today, indexed by severity and affected component.
–AskWoody.com, which keeps tabs on any developing problems related to the availability or installation of these updates.
Microsoft Corp. today released software updates to quash 130 security bugs in its Windows operating systems and related software, including at least five flaws that are already seeing active exploitation. Meanwhile, Apple customers have their own zero-day woes again this month: On Monday, Apple issued (and then quickly pulled) an emergency update to fix a zero-day vulnerability that is being exploited on MacOS and iOS devices.
On July 10, Apple pushed a “Rapid Security Response” update to fix a code execution flaw in the Webkit browser component built into iOS, iPadOS, and macOS Ventura. Almost as soon as the patch went out, Apple pulled the software because it was reportedly causing problems loading certain websites. MacRumors says Apple will likely re-release the patches when the glitches have been addressed.
Launched in May, Apple’s Rapid Security Response updates are designed to address time-sensitive vulnerabilities, and this is the second month Apple has used it. July marks the sixth month this year that Apple has released updates for zero-day vulnerabilities — those that get exploited by malware or malcontents before there is an official patch available.
If you rely on Apple devices and don’t have automatic updates enabled, please take a moment to check the patch status of your various iDevices. The latest security update that includes the fix for the zero-day bug should be available in iOS/iPadOS 16.5.1, macOS 13.4.1, and Safari 16.5.2.
On the Windows side, there are at least four vulnerabilities patched this month that earned high CVSS (badness) scores and that are already being exploited in active attacks, according to Microsoft. They include CVE-2023-32049, which is a hole in Windows SmartScreen that lets malware bypass security warning prompts; and CVE-2023-35311 allows attackers to bypass security features in Microsoft Outlook.
The two other zero-day threats this month for Windows are both privilege escalation flaws. CVE-2023-32046 affects a core Windows component called MSHTML, which is used by Windows and other applications, like Office, Outlook and Skype. CVE-2023-36874 is an elevation of privilege bug in the Windows Error Reporting Service.
Many security experts expected Microsoft to address a fifth zero-day flaw — CVE-2023-36884 — a remote code execution weakness in Office and Windows.
“Surprisingly, there is no patch yet for one of the five zero-day vulnerabilities,” said Adam Barnett, lead software engineer at Rapid7. “Microsoft is actively investigating publicly disclosed vulnerability, and promises to update the advisory as soon as further guidance is available.”
Barnett notes that Microsoft links exploitation of this vulnerability with Storm-0978, the software giant’s name for a cybercriminal group based out of Russia that is identified by the broader security community as RomCom.
“Exploitation of CVE-2023-36884 may lead to installation of the eponymous RomCom trojan or other malware,” Barnett said. “[Microsoft] suggests that RomCom / Storm-0978 is operating in support of Russian intelligence operations. The same threat actor has also been associated with ransomware attacks targeting a wide array of victims.”
Microsoft’s advisory on CVE-2023-36884 is pretty sparse, but it does include a Windows registry hack that should help mitigate attacks on this vulnerability. Microsoft has also published a blog post about phishing campaigns tied to Storm-0978 and to the exploitation of this flaw.
Barnett said it’s while it’s possible that a patch will be issued as part of next month’s Patch Tuesday, Microsoft Office is deployed just about everywhere, and this threat actor is making waves.
“Admins should be ready for an out-of-cycle security update for CVE-2023-36884,” he said.
Microsoft also today released new details about how it plans to address the existential threat of malware that is cryptographically signed by…wait for it….Microsoft.
In late 2022, security experts at Sophos, Trend Micro and Cisco warned that ransomware criminals were using signed, malicious drivers in an attempt to evade antivirus and endpoint detection and response (EDR) tools.
In a blog post today, Sophos’s Andrew Brandt wrote that Sophos identified 133 malicious Windows driver files that were digitally signed since April 2021, and found 100 of those were actually signed by Microsoft. Microsoft said today it is taking steps to ensure those malicious driver files can no longer run on Windows computers.
As KrebsOnSecurity noted in last month’s story on malware signing-as-a-service, code-signing certificates are supposed to help authenticate the identity of software publishers, and provide cryptographic assurance that a signed piece of software has not been altered or tampered with. Both of these qualities make stolen or ill-gotten code-signing certificates attractive to cybercriminal groups, who prize their ability to add stealth and longevity to malicious software.
Dan Goodin at Ars Technica contends that whatever Microsoft may be doing to keep maliciously signed drivers from running on Windows is being bypassed by hackers using open source software that is popular with video game cheaters.
“The software comes in the form of two software tools that are available on GitHub,” Goodin explained. “Cheaters use them to digitally sign malicious system drivers so they can modify video games in ways that give the player an unfair advantage. The drivers clear the considerable hurdle required for the cheat code to run inside the Windows kernel, the fortified layer of the operating system reserved for the most critical and sensitive functions.”
Meanwhile, researchers at Cisco’s Talos security team found multiple Chinese-speaking threat groups have repurposed the tools—one apparently called “HookSignTool” and the other “FuckCertVerifyTimeValidity.”
“Instead of using the kernel access for cheating, the threat actors use it to give their malware capabilities it wouldn’t otherwise have,” Goodin said.
For a closer look at the patches released by Microsoft today, check out the always-thorough Patch Tuesday roundup from the SANS Internet Storm Center. And it’s not a bad idea to hold off updating for a few days until Microsoft works out any kinks in the updates: AskWoody.com usually has the lowdown on any patches that may be causing problems for Windows users.
And as ever, please consider backing up your system or at least your important documents and data before applying system updates. If you encounter any problems with these updates, please drop a note about it here in the comments.
The U.S. government agency in charge of improving the nation’s cybersecurity posture is ordering all federal agencies to take new measures to restrict access to Internet-exposed networking equipment. The directive comes amid a surge in attacks targeting previously unknown vulnerabilities in widely used security and networking appliances.
Under a new order from the Cybersecurity and Infrastructure Security Agency (CISA), federal agencies will have 14 days to respond to any reports from CISA about misconfigured or Internet-exposed networking equipment. The directive applies to any networking devices — such as firewalls, routers and load balancers — that allow remote authentication or administration.
The order requires federal departments to limit access so that only authorized users on an agency’s local or internal network can reach the management interfaces of these devices. CISA’s mandate follows a slew of recent incidents wherein attackers exploited zero-day flaws in popular networking products to conduct ransomware and cyber espionage attacks on victim organizations.
Earlier today, incident response firm Mandiant revealed that since at least October 2022, Chinese cyber spies have been exploiting a zero-day vulnerability in many email security gateway (ESG) appliances sold by California-based Barracuda Networks to hoover up email from organizations using these devices.
Barracuda was alerted to the exploitation of a zero-day in its products in mid-May, and two days later the company pushed a security update to address the flaw in all affected devices. But last week, Barracuda took the highly unusual step of offering to replace compromised ESGs, evidently in response to malware that altered the systems in such a fundamental way that they could no longer be secured remotely with software updates.
According to Mandiant, a previously unidentified Chinese hacking group was responsible for exploiting the Barracuda flaw, and appeared to be searching through victim organization email records for accounts “belonging to individuals working for a government with political or strategic interest to [China] while this victim government was participating in high-level, diplomatic meetings with other countries.”
When security experts began raising the alarm about a possible zero-day in Barracuda’s products, the Chinese hacking group altered their tactics, techniques and procedures (TTPs) in response to Barracuda’s efforts to contain and remediate the incident, Mandiant found.
Mandiant said the attackers will continue to change their tactics and malware, “especially as network defenders continue to take action against this adversary and their activity is further exposed by the infosec community.”
Meanwhile, this week we learned more details about the ongoing exploitation of a zero-day flaw in a broad range of virtual private networking (VPN) products made by Fortinet — devices many organizations rely on to facilitate remote network access for employees.
On June 11, Fortinet released a half-dozen security updates for its FortiOS firmware, including a weakness that researchers said allows an attacker to run malware on virtually any Fortinet SSL VPN appliance. The researchers found that just being able to reach the management interface for a vulnerable Fortinet SSL VPN appliance was enough to completely compromise the devices.
“This is reachable pre-authentication, on every SSL VPN appliance,” French vulnerability researcher Charles Fol tweeted. “Patch your #Fortigate.”
In details published on June 12, Fortinet confirmed that one of the vulnerabilities (CVE-2023-27997) is being actively exploited. The company said it discovered the weakness in an internal code audit that began in January 2023 — when it learned that Chinese hackers were exploiting a different zero-day flaw in its products.
Shodan.io, the search engine made for finding Internet of Things devices, reports that there are currently more than a half-million vulnerable Fortinet devices reachable via the public Internet.
The new cybersecurity directive from CISA orders agencies to remove any networking device management interfaces from the internet by making them only accessible from an internal enterprise network (CISA recommends an isolated management network). CISA also says agencies should “deploy capabilities, as part of a Zero Trust Architecture, that enforce access control to the interface through a policy enforcement point separate from the interface itself (preferred action).”
Security experts say CISA’s directive highlights the reality that cyberspies and ransomware gangs are making it increasingly risky for organizations to expose any devices to the public Internet, because these groups have strong incentives to probe such devices for previously unknown security vulnerabilities.
The most glaring example of this dynamic can be seen in the frequency with which ransomware groups have discovered and pounced on zero-day flaws in widely-used file transfer applications. One ransomware gang in particular — Cl0p — has repeatedly exploited zero day bugs in various file transfer appliances to extort tens of millions of dollars from hundreds of ransomware victims.
On February 2, KrebsOnSecurity broke the news that attackers were exploiting a zero-day vulnerability in the GoAnywhere file transfer appliance by Fortra. By the time security updates were available to fix the vulnerability, Cl0p had already used it to steal data from more than a hundred organizations running Fortra’s appliance.
According to CISA, on May 27, Cl0p began exploiting a previously unknown flaw in MOVEit Transfer, a popular Internet-facing file transfer application. MOVEit parent Progress Software has since released security updates to address the weakness, but Cl0p claims to have already used it to compromise hundreds of victim organizations. TechCrunch has been tracking the fallout from victim organizations, which range from banks and insurance providers to universities and healthcare entities.
The always on-point weekly security news podcast Risky Business has recently been urging organizations to jettison any and all FTP appliances, noting that Cl0p (or another crime gang) is likely to visit the same treatment on other FTP appliance vendors.
But that sound advice doesn’t exactly scale for mid-tier networking devices like Barracuda ESGs or Fortinet SSL VPNs, which are particularly prominent in small to mid-sized organizations.
“It’s not like FTP services, you can’t tell an enterprise [to] turn off the VPN [because] the productivity hit of disconnecting the VPN is terminal, it’s a non-starter,” Risky Business co-host Adam Boileau said on this week’s show. “So how to mitigate the impact of having to use a domain-joined network appliance at the edge of your network that is going to get zero-day in it? There’s no good answer.”
Risky Business founder Patrick Gray said the COVID-19 pandemic breathed new life into entire classes of networking appliances that rely on code which was never designed with today’s threat models in mind.
“In the years leading up to the pandemic, the push towards identity-aware proxies and zero trust everything and moving away from this type of equipment was gradual, but it was happening,” Gray said. “And then COVID-19 hit and everybody had to go work from home, and there really was one option to get going quickly — which was to deploy VPN concentrators with enterprise features.”
Gray said the security industry had been focused on building the next generation of remote access tools that are more security-hardened, but when the pandemic hit organizations scrambled to cobble together whatever they could.
“The only stuff available in the market was all this old crap that is not QA’d properly, and every time you shake them CVEs fall out,” Gray remarked, calling the pandemic, “a shot in the arm” to companies like Fortinet and Barracuda.
“They sold so many VPNs through the pandemic and this is the hangover,” Gray said. “COVID-19 extended the life of these companies and technologies, and that’s unfortunate.”
Microsoft Corp. today released software updates to fix dozens of security vulnerabilities in its Windows operating systems and other software. This month’s relatively light patch load has another added bonus for system administrators everywhere: It appears to be the first Patch Tuesday since March 2022 that isn’t marred by the active exploitation of a zero-day vulnerability in Microsoft’s products.
June’s Patch Tuesday features updates to plug at least 70 security holes, and while none of these are reported by Microsoft as exploited in-the-wild yet, Redmond has flagged several in particular as “more likely to be exploited.”
Top of the list on that front is CVE-2023-29357, which is a “critical” bug in Microsoft SharePoint Server that can be exploited by an unauthenticated attacker on the same network. This SharePoint flaw earned a CVSS rating of 9.8 (10.0 is the most dangerous).
“An attacker able to gain admin access to an internal SharePoint server could do a lot of harm to an organization,” said Kevin Breen, director of cyber threat research at Immersive Labs. “Gaining access to sensitive and privileged documents, stealing and deleting documents as part of a ransomware attack or replacing real documents with malicious copies to further infect users in the organization.”
There are at least three other vulnerabilities fixed this month that earned a collective 9.8 CVSS score, and they all concern a widely-deployed component called the Windows Pragmatic General Multicast (PGM), which is used for delivering multicast data — such as video streaming or online gaming.
Security firm Action1 says all three bugs (CVE-2023-32015, CVE-2023-32014, and CVE-2023-29363) can be exploited over the network without requiring any privileges or user interaction, and affected systems include all versions of Windows Server 2008 and later, as well as Windows 10 and later.
It wouldn’t be a proper Patch Tuesday if we also didn’t also have scary security updates for organizations still using Microsoft Exchange for email. Breen said this month’s Exchange bugs (CVE-2023-32031 and CVE-2023-28310) closely mirror the vulnerabilities identified as part of ProxyNotShell exploits, where an authenticated user in the network could exploit a vulnerability in the Exchange to gain code execution on the server.
Breen said while Microsoft’s patch notes indicate that an attacker must already have gained access to a vulnerable host in the network, this is typically achieved through social engineering attacks with spear phishing to gain initial access to a host before searching for other internal targets.
“Just because your Exchange server doesn’t have internet-facing authentication doesn’t mean it’s protected,” Breen said, noting that Microsoft says the Exchange flaws are not difficult for attackers to exploit.
For a closer look at the patches released by Microsoft today and indexed by severity and other metrics, check out the always-useful Patch Tuesday roundup from the SANS Internet Storm Center. And it’s not a bad idea to hold off updating for a few days until Microsoft works out any kinks in the updates: AskWoody.com usually has the lowdown on any patches that may be causing problems for Windows users.
As always, please consider backing up your system or at least your important documents and data before applying system updates. And if you run into any problems with these updates, please drop a note about it here in the comments.
It’s not often that a zero-day vulnerability causes a network security vendor to urge customers to physically remove and decommission an entire line of affected hardware — as opposed to just applying software updates. But experts say that is exactly what transpired this week with Barracuda Networks, as the company struggled to combat a sprawling malware threat which appears to have undermined its email security appliances in such a fundamental way that they can no longer be safely updated with software fixes.
The Barracuda Email Security Gateway (ESG) 900 appliance.
Campbell, Calif. based Barracuda said it hired incident response firm Mandiant on May 18 after receiving reports about unusual traffic originating from its Email Security Gateway (ESG) devices, which are designed to sit at the edge of an organization’s network and scan all incoming and outgoing email for malware.
On May 19, Barracuda identified that the malicious traffic was taking advantage of a previously unknown vulnerability in its ESG appliances, and on May 20 the company pushed a patch for the flaw to all affected appliances (CVE-2023-2868).
In its security advisory, Barracuda said the vulnerability existed in the Barracuda software component responsible for screening attachments for malware. More alarmingly, the company said it appears attackers first started exploiting the flaw in October 2022.
But on June 6, Barracuda suddenly began urging its ESG customers to wholesale rip out and replace — not patch — affected appliances.
“Impacted ESG appliances must be immediately replaced regardless of patch version level,” the company’s advisory warned. “Barracuda’s recommendation at this time is full replacement of the impacted ESG.”
In a statement, Barracuda said it will be providing the replacement product to impacted customers at no cost, and that not all ESG appliances were compromised.
“No other Barracuda product, including our SaaS email solutions, were impacted by this vulnerability,” the company said. “If an ESG appliance is displaying a notification in the User Interface, the ESG appliance had indicators of compromise. If no notification is displayed, we have no reason to believe that the appliance has been compromised at this time.”
Nevertheless, the statement says that “out of an abundance of caution and in furtherance of our containment strategy, we recommend impacted customers replace their compromised appliance.”
“As of June 8, 2023, approximately 5% of active ESG appliances worldwide have shown any evidence of known indicators of compromise due to the vulnerability,” the statement continues. “Despite deployment of additional patches based on known IOCs, we continue to see evidence of ongoing malware activity on a subset of the compromised appliances. Therefore, we would like customers to replace any compromised appliance with a new unaffected device.”
Rapid7‘s Caitlin Condon called this remarkable turn of events “fairly stunning,” and said there appear to be roughly 11,000 vulnerable ESG devices still connected to the Internet worldwide.
“The pivot from patch to total replacement of affected devices is fairly stunning and implies the malware the threat actors deployed somehow achieves persistence at a low enough level that even wiping the device wouldn’t eradicate attacker access,” Condon wrote.
Barracuda said the malware was identified on a subset of appliances that allowed the attackers persistent backdoor access to the devices, and that evidence of data exfiltration was identified on some systems.
Rapid7 said it has seen no evidence that attackers are using the flaw to move laterally within victim networks. But that may be small consolation for Barracuda customers now coming to terms with the notion that foreign cyberspies probably have been hoovering up all their email for months.
Nicholas Weaver, a researcher at University of California, Berkeley’s International Computer Science Institute (ICSI), said it is likely that the malware was able to corrupt the underlying firmware that powers the ESG devices in some irreparable way.
“One of the goals of malware is to be hard to remove, and this suggests the malware compromised the firmware itself to make it really hard to remove and really stealthy,” Weaver said. “That’s not a ransomware actor, that’s a state actor. Why? Because a ransomware actor doesn’t care about that level of access. They don’t need it. If they’re going for data extortion, it’s more like a smash-and-grab. If they’re going for data ransoming, they’re encrypting the data itself — not the machines.”
In addition to replacing devices, Barracuda says ESG customers should also rotate any credentials connected to the appliance(s), and check for signs of compromise dating back to at least October 2022 using the network and endpoint indicators the company has released publicly.
Update, June 9, 11:55 a.m. ET: Barracuda has issued an updated statement about the incident, portions of which are now excerpted above.
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Microsoft today released software updates to fix at least four dozen security holes in its Windows operating systems and other software, including patches for two zero-day vulnerabilities that are already being exploited in active attacks.
First up in May’s zero-day flaws is CVE-2023-29336, which is an “elevation of privilege” weakness in Windows which has a low attack complexity, requires low privileges, and no user interaction. However, as the SANS Internet Storm Center points out, the attack vector for this bug is local.
“Local Privilege escalation vulnerabilities are a key part of attackers’ objectives,” said Kevin Breen, director of cyber threat research at Immersive Labs. “Once they gain initial access they will seek administrative or SYSTEM-level permissions. This can allow the attacker to disable security tooling and deploy more attacker tools like Mimikatz that lets them move across the network and gain persistence.”
The zero-day patch that has received the most attention so far is CVE-2023-24932, which is a Secure Boot Security Feature Bypass flaw that is being actively exploited by “bootkit” malware known as “BlackLotus.” A bootkit is dangerous because it allows the attacker to load malicious software before the operating system even starts up.
According to Microsoft’s advisory, an attacker would need physical access or administrative rights to a target device, and could then install an affected boot policy. Microsoft gives this flaw a CVSS score of just 6.7, rating it as “Important.”
Adam Barnett, lead software engineer at Rapid7, said CVE-2023-24932 deserves a considerably higher threat score.
“Microsoft warns that an attacker who already has Administrator access to an unpatched asset could exploit CVE-2023-24932 without necessarily having physical access,” Barnett said. “Therefore, the relatively low CVSSv3 base score of 6.7 isn’t necessarily a reliable metric in this case.”
Barnett said Microsoft has provided a supplementary guidance article specifically calling out the threat posed by BlackLotus malware, which loads ahead of the operating system on compromised assets, and provides attackers with an array of powerful evasion, persistence, and Command & Control (C2) techniques, including deploying malicious kernel drivers, and disabling Microsoft Defender or Bitlocker.
“Administrators should be aware that additional actions are required beyond simply applying the patches,” Barnett advised. “The patch enables the configuration options necessary for protection, but administrators must apply changes to UEFI config after patching. The attack surface is not limited to physical assets, either; Windows assets running on some VMs, including Azure assets with Secure Boot enabled, also require these extra remediation steps for protection. Rapid7 has noted in the past that enabling Secure Boot is a foundational protection against driver-based attacks. Defenders ignore this vulnerability at their peril.”
In addition to the two zero-days fixed this month, Microsoft also patched five remote code execution (RCE) flaws in Windows, two of which have notably high CVSS scores.
CVE-2023-24941 affects the Windows Network File System, and can be exploited over the network by making an unauthenticated, specially crafted request. Microsoft’s advisory also includes mitigation advice. The CVSS for this vulnerability is 9.8 – the highest of all the flaws addressed this month.
Meanwhile, CVE-2023-28283 is a critical bug in the Windows Lightweight Directory Access Protocol (LDAP) that allows an unauthenticated attacker to execute malicious code on the vulnerable device. The CVSS for this vulnerability is 8.1, but Microsoft says exploiting the flaw may be tricky and unreliable for attackers.
Another vulnerability patched this month that was disclosed publicly before today (but not yet seen exploited in the wild) is CVE-2023-29325, a weakness in Microsoft Outlook and Explorer that can be exploited by attackers to remotely install malware. Microsoft says this vulnerability can be exploited merely by viewing a specially-crafted email in the Outlook Preview Pane.
“To help protect against this vulnerability, we recommend users read email messages in plain text format,” Microsoft’s writeup on CVE-2023-29325 advises.
“If an attacker were able to exploit this vulnerability, they would gain remote access to the victim’s account, where they could deploy additional malware,” Immersive’s Breen said. “This kind of exploit will be highly sought after by e-crime and ransomware groups where, if successfully weaponized, could be used to target hundreds of organizations with very little effort.”
For more details on the updates released today, check out roundups by Action1, Automox and Qualys, If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
Microsoft today released software updates to plug 100 security holes in its Windows operating systems and other software, including a zero-day vulnerability that is already being used in active attacks. Not to be outdone, Apple has released a set of important updates addressing two zero-day vulnerabilities that are being used to attack iPhones, iPads and Macs.
On April 7, Apple issued emergency security updates to fix two weaknesses that are being actively exploited, including CVE-2023-28206, which can be exploited by apps to seize control over a device. CVE-2023-28205 can be used by a malicious or hacked website to install code.
Both vulnerabilities are addressed in iOS/iPadOS 16.4.1, iOS 15.7.5, and macOS 12.6.5 and 11.7.6. If you use Apple devices and you don’t have automatic updates enabled (they are on by default), you should probably take care of that soon as detailed instructions on how to attack CVE-2023-28206 are now public.
Microsoft’s bevy of 100 security updates released today include CVE-2023-28252, which is a weakness in Windows that Redmond says is under active attack. The vulnerability is in the Windows Common Log System File System (CLFS) driver, a core Windows component that was the source of attacks targeting a different zero-day vulnerability in February 2023.
“If it seems familiar, that’s because there was a similar 0-day patched in the same component just two months ago,” said Dustin Childs at the Trend Micro Zero Day Initiative. “To me, that implies the original fix was insufficient and attackers have found a method to bypass that fix. As in February, there is no information about how widespread these attacks may be. This type of exploit is typically paired with a code execution bug to spread malware or ransomware.”
According to the security firm Qualys, this vulnerability has been leveraged by cyber criminals to deploy Nokoyawa ransomware.
“This is a relatively new strain for which there is some open source intel to suggest that it is possibly related to Hive ransomware – one of the most notable ransomware families of 2021 and linked to breaches of over 300+ organizations in a matter of just a few months,” said Bharat Jogi, director of vulnerability and threat research at Qualys.
Jogi said while it is still unclear which exact threat actor is targeting CVE-2023-28252, targets have been observed in South and North America, regions across Asia and at organizations in the Middle East.
Satnam Narang at Tenable notes that CVE-2023-28252 is also the second CLFS zero-day disclosed to Microsoft by researchers from Mandiant and DBAPPSecurity (CVE-2022-37969), though it is unclear if both of these discoveries are related to the same attacker.
Seven of the 100 vulnerabilities Microsoft fixed today are rated “Critical,” meaning they can be used to install malicious code with no help from the user. Ninety of the flaws earned Redmond’s slightly less-dire “Important” label, which refers to weaknesses that can be used to undermine the security of the system but which may require some amount of user interaction.
Narang said Microsoft has rated nearly 90% of this month’s vulnerabilities as “Exploitation Less Likely,” while just 9.3% of flaws were rated as “Exploitation More Likely.” Kevin Breen at Immersive Labs zeroed in on several notable flaws in that 9.3%, including CVE-2023-28231, a remote code execution vulnerability in a core Windows network process (DHCP) with a CVSS score of 8.8.
“‘Exploitation more likely’ means it’s not being actively exploited but adversaries may look to try and weaponize this one,” Breen said. “Micorosft does note that successful exploitation requires an attacker to have already gained initial access to the network. This could be via social engineering, spear phishing attacks, or exploitation of other services.”
Breen also called attention to CVE-2023-28220 and CVE-2023-28219 — a pair of remote code execution vulnerabilities affecting Windows Remote Access Servers (RAS) that also earned Microsoft’s “exploitation more likely” label.
“An attacker can exploit this vulnerability by sending a specially crafted connection request to a RAS server, which could lead to remote code execution,” Breen said. While not standard in all organizations, RAS servers typically have direct access from the Internet where most users and services are connected. This makes it extremely enticing for attackers as they don’t need to socially engineer their way into an organization. They can simply scan the internet for RAS servers and automate the exploitation of vulnerable devices.”
For more details on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
Microsoft on Tuesday released updates to quash at least 74 security bugs in its Windows operating systems and software. Two of those flaws are already being actively attacked, including an especially severe weakness in Microsoft Outlook that can be exploited without any user interaction.
The Outlook vulnerability (CVE-2023-23397) affects all versions of Microsoft Outlook from 2013 to the newest. Microsoft said it has seen evidence that attackers are exploiting this flaw, which can be done without any user interaction by sending a booby-trapped email that triggers automatically when retrieved by the email server — before the email is even viewed in the Preview Pane.
While CVE-2023-23397 is labeled as an “Elevation of Privilege” vulnerability, that label doesn’t accurately reflect its severity, said Kevin Breen, director of cyber threat research at Immersive Labs.
Known as an NTLM relay attack, it allows an attacker to get someone’s NTLM hash [Windows account password] and use it in an attack commonly referred to as “Pass The Hash.”
“The vulnerability effectively lets the attacker authenticate as a trusted individual without having to know the person’s password,” Breen said. “This is on par with an attacker having a valid password with access to an organization’s systems.”
Security firm Rapid7 points out that this bug affects self-hosted versions of Outlook like Microsoft 365 Apps for Enterprise, but Microsoft-hosted online services like Microsoft 365 are not vulnerable.
The other zero-day flaw being actively exploited in the wild — CVE-2023-24880 — is a “Security Feature Bypass” in Windows SmartScreen, part of Microsoft’s slate of endpoint protection tools.
Patch management vendor Action1 notes that the exploit for this bug is low in complexity and requires no special privileges. But it does require some user interaction, and can’t be used to gain access to private information or privileges. However, the flaw can allow other malicious code to run without being detected by SmartScreen reputation checks.
Dustin Childs, head of threat awareness at Trend Micro’s Zero Day Initiative, said CVE-2023-24880 allows attackers to create files that would bypass Mark of the Web (MOTW) defenses.
“Protective measures like SmartScreen and Protected View in Microsoft Office rely on MOTW, so bypassing these makes it easier for threat actors to spread malware via crafted documents and other infected files that would otherwise be stopped by SmartScreen,” Childs said.
Seven other vulnerabilities Microsoft patched this week earned its most-dire “critical” severity label, meaning the updates address security holes that could be exploited to give the attacker full, remote control over a Windows host with little or no interaction from the user.
Also this week, Adobe released eight patches addressing a whopping 105 security holes across a variety of products, including Adobe Photoshop, Cold Fusion, Experience Manager, Dimension, Commerce, Magento, Substance 3D Stager, Cloud Desktop Application, and Illustrator.
For a more granular rundown on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
Microsoft is sending the world a whole bunch of love today, in the form of patches to plug dozens of security holes in its Windows operating systems and other software. This year’s special Valentine’s Day Patch Tuesday includes fixes for a whopping three different “zero-day” vulnerabilities that are already being used in active attacks.
Microsoft’s security advisories are somewhat sparse with details about the zero-day bugs. Redmond flags CVE-2023-23376 as an “Important” elevation of privilege vulnerability in the Windows Common Log File System Driver, which is present in Windows 10 and 11 systems, as well as many server versions of Windows.
“Sadly, there’s just a little solid information about this privilege escalation,” said Dustin Childs, head of threat awareness at Trend Micro’s Zero Day Initiative. “Microsoft does note that the vulnerability would allow an attacker to exploit code as SYSTEM, which would allow them to completely take over a target. This is likely being chained with a remote code execution bug to spread malware or ransomware. Considering this was discovered by Microsoft’s Threat Intelligence Center, it could mean it was used by advanced threat actors. Either way, make sure you test and roll these fixes quickly.”
The zero-day CVE-2023-21715 is a weakness in Microsoft Office that Redmond describes as a “security feature bypass vulnerability.”
“Microsoft lists this as under active exploit, but they offer no info on how widespread these exploits may be,” Childs said. “Based on the write-up, it sounds more like a privilege escalation than a security feature bypass, but regardless, active attacks in a common enterprise application shouldn’t be ignored. It’s always alarming when a security feature is not just bypassed but exploited. Let’s hope the fix comprehensively addresses the problem.”
The third zero-day flaw already seeing exploitation is CVE-2023-21823, which is another elevation of privilege weakness — this one in the Microsoft Windows Graphic component. Researchers at cybersecurity forensics firm Mandiant were credited with reporting the bug.
Kevin Breen, director of cyber threat research at Immersive Labs, pointed out that the security bulletin for CVE-2023-21823 specifically calls out OneNote as being a vulnerable component for the vulnerability.
“In recent weeks, we have seen an increase in the use of OneNote files as part of targeted malware campaigns,” Breen said. “Patches for this are delivered via the app stores and not through the typical formats, so it’s important to double check your organization’s policies.”
Microsoft fixed another Office vulnerability in CVE-2023-21716, which is a Microsoft Word bug that can lead to remote code execution — even if a booby-trapped Word document is merely viewed in the preview pane of Microsoft Outlook. This security hole has a CVSS (severity) score of 9.8 out of a possible 10.
Microsoft also has more valentines for organizations that rely on Microsoft Exchange Server to handle email. Redmond patched three Exchange Server flaws (CVE-2023-21706, CVE-2023-21707, and CVE-2023-21529), all of which Microsoft says are remote code execution flaws that are likely to be exploited.
Microsoft said authentication is required to exploit these bugs, but then again threat groups that attack Exchange vulnerabilities also tend to phish targets for their Exchange credentials.
Microsoft isn’t alone in dropping fixes for scary, ill-described zero-day flaws. Apple on Feb. 13 released an update for iOS that resolves a zero-day vulnerability in Webkit, Apple’s open source browser engine. Johannes Ullrich at the SANS Internet Storm Center notes that in addition to the WebKit problem, Apple fixed a privilege escalation issue. Both flaws are fixed in iOS 16.3.1.
“This privilege escalation issue could be used to escape the browser sandbox and gain full system access after executing code via the WebKit vulnerability,” Ullrich warned.
On a lighter note (hopefully), Microsoft drove the final nail in the coffin for Internet Explorer 11 (IE11). According to Redmond, the out-of-support IE11 desktop application was permanently disabled on certain versions of Windows 10 on February 14, 2023 through a Microsoft Edge update.
“All remaining consumer and commercial devices that were not already redirected from IE11 to Microsoft Edge were redirected with the Microsoft Edge update. Users will be unable to reverse the change,” Microsoft explained. “Additionally, redirection from IE11 to Microsoft Edge will be included as part of all future Microsoft Edge updates. IE11 visual references, such as the IE11 icons on the Start Menu and taskbar, will be removed by the June 2023 Windows security update (“B” release) scheduled for June 13, 2023.”
For a more granular rundown on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
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Microsoft today released updates to fix nearly 100 security flaws in its Windows operating systems and other software. Highlights from the first Patch Tuesday of 2023 include a zero-day vulnerability in Windows, printer software flaws reported by the U.S. National Security Agency, and a critical Microsoft SharePoint Server bug that allows a remote, unauthenticated attacker to make an anonymous connection.
At least 11 of the patches released today are rated “Critical” by Microsoft, meaning they could be exploited by malware or malcontents to seize remote control over vulnerable Windows systems with little or no help from users.
Of particular concern for organizations running Microsoft SharePoint Server is CVE-2023-21743. This is a Critical security bypass flaw that could allow a remote, unauthenticated attacker to make an anonymous connection to a vulnerable SharePoint server. Microsoft says this flaw is “more likely to be exploited” at some point.
But patching this bug may not be as simple as deploying Microsoft updates. Dustin Childs, head of threat awareness at Trend Micro’s Zero Day Initiative, said sysadmins need to take additional measures to be fully protected from this vulnerability.
“To fully resolve this bug, you must also trigger a SharePoint upgrade action that’s also included in this update,” Childs said. “Full details on how to do this are in the bulletin. Situations like this are why people who scream ‘Just patch it!’ show they have never actually had to patch an enterprise in the real world.”
Eighty-seven of the vulnerabilities earned Redmond’s slightly less dire “Important” severity rating. That designation describes vulnerabilities “whose exploitation could result in compromise of the confidentiality, integrity, or availability of user data, or of the integrity or availability of processing resources.”
Among the more Important bugs this month is CVE-2023-21674, which is an “elevation of privilege” weakness in most supported versions of Windows that has already been abused in active attacks.
Satnam Narang, senior staff research engineer at Tenable, said although details about the flaw were not available at the time Microsoft published its advisory on Patch Tuesday, it appears this was likely chained together with a vulnerability in a Chromium-based browser such as Google Chrome or Microsoft Edge in order to break out of a browser’s sandbox and gain full system access.
“Vulnerabilities like CVE-2023-21674 are typically the work of advanced persistent threat (APT) groups as part of targeted attacks,” Narang said. “The likelihood of future widespread exploitation of an exploit chain like this is limited due to auto-update functionality used to patch browsers.”
By the way, when was the last time you completely closed out your Web browser and restarted it? Some browsers will automatically download and install new security updates, but the protection from those updates usually only happens after you restart the browser.
Speaking of APT groups, the U.S. National Security Agency is credited with reporting CVE-2023-21678, which is another “important” vulnerability in the Windows Print Spooler software.
There have been so many vulnerabilities patched in Microsoft’s printing software over the past year (including the dastardly PrintNightmare attacks and borked patches) that KrebsOnSecurity has joked about Patch Tuesday reports being sponsored by Print Spooler. Tenable’s Narang points out that this is the third Print Spooler flaw the NSA has reported in the last year.
Kevin Breen at Immersive Labs called special attention to CVE-2023-21563, which is a security feature bypass in BitLocker, the data and disk encryption technology built into enterprise versions of Windows.
“For organizations that have remote users, or users that travel, this vulnerability may be of interest,” Breen said. “We rely on BitLocker and full-disk encryption tools to keep our files and data safe in the event a laptop or device is stolen. While information is light, this appears to suggest that it could be possible for an attacker to bypass this protection and gain access to the underlying operating system and its contents. If security teams are not able to apply this patch, one potential mitigation could be to ensure Remote Device Management is deployed with the ability to remotely disable and wipe assets.”
There are also two Microsoft Exchange vulnerabilities patched this month — CVE-2023-21762 and CVE-2023-21745. Given the rapidity with which threat actors exploit new Exchange bugs to steal corporate email and infiltrate vulnerable systems, organizations using Exchange should patch immediately. Microsoft’s advisory says these Exchange flaws are indeed “more likely to be exploited.”
Adobe released four patches addressing 29 flaws in Adobe Acrobat and Reader, InDesign, InCopy, and Adobe Dimension. The update for Reader fixes 15 bugs with eight of these being ranked Critical in severity (allowing arbitrary code execution if an affected system opened a specially crafted file).
For a more granular rundown on the updates released today, see the SANS Internet Storm Center roundup. Nearly 100 updates is a lot, and there are bound to be a few patches that cause problems for organizations and end users. When that happens, AskWoody.com usually has the lowdown.
Please consider backing up your data and/or imaging your system before applying any updates. And please sound off in the comments if you experience any problems as a result of these patches.
Microsoft has released its final monthly batch of security updates for 2022, fixing more than four dozen security holes in its various Windows operating systems and related software. The most pressing patches include a zero-day in a Windows feature that tries to flag malicious files from the Web, a critical bug in PowerShell, and a dangerous flaw in Windows 11 systems that was detailed publicly prior to this week’s Patch Tuesday.
The security updates include patches for Azure, Microsoft Edge, Office, SharePoint Server, SysInternals, and the .NET framework. Six of the update bundles earned Microsoft’s most dire “critical” rating, meaning they fix vulnerabilities that malware or malcontents can use to remotely commandeer an unpatched Windows system — with little to no interaction on the part of the user.
The bug already seeing exploitation is CVE-2022-44698, which allows attackers to bypass the Windows SmartScreen security feature. The vulnerability allows attackers to craft documents that won’t get tagged with Microsoft’s “Mark of the Web,” despite being downloaded from untrusted sites.
“This means no Protected View for Microsoft Office documents, making it easier to get users to do sketchy things like execute malicious macros, said Greg Wiseman, product manager at security firm Rapid7. This is the second Mark of the Web flaw Microsoft has patched in as many months; both were first publicly detailed over the past two months on Twitter by security researcher Will Dormann.
Publicly disclosed (but not actively exploited for now) is CVE-2022-44710, which is an elevation of privilege flaw in the DirectX graphics component of Windows 11.
Another notable critical bug is CVE-2022-41076, a remote code execution flaw in PowerShell — a key component of Windows that makes it easier to automate system tasks and configurations.
Kevin Breen at Immersive Labs said while Microsoft doesn’t share much detail about CVE-2022-41076 apart from the designation ‘Exploitation More Likely,’ they also note that successful exploitation requires an attacker to take additional actions to prepare the target environment.
“What actions are required is not clear; however, we do know that exploitation requires an authenticated user level of access,” Breen said. “This combination suggests that the exploit requires a social engineering element, and would likely be seen in initial infections using attacks like MalDocs or LNK files.”
Speaking of malicious documents, Trend Micro’s Zero Day Initiative highlights CVE-2022-44713, a spoofing vulnerability in Outlook for Mac.
“We don’t often highlight spoofing bugs, but anytime you’re dealing with a spoofing bug in an e-mail client, you should take notice,” ZDI’s Dustin Childs wrote. “This vulnerability could allow an attacker to appear as a trusted user when they should not be. Now combine this with the SmartScreen Mark of the Web bypass and it’s not hard to come up with a scenario where you receive an e-mail that appears to be from your boss with an attachment entitled “Executive_Compensation.xlsx”. There aren’t many who wouldn’t open that file in that scenario.”
Microsoft also released guidance on reports that certain software drivers certified by Microsoft’s Windows Hardware Developer Program were being used maliciously in post-exploitation activity.
Three different companies reported evidence that malicious hackers were using these signed malicious driver files to lay the groundwork for ransomware deployment inside victim organizations. One of those companies, Sophos, published a blog post Tuesday detailing how the activity was tied to the Russian ransomware group Cuba, which has extorted an estimated $60 million from victims since 2019.
Of course, not all scary and pressing security threats are Microsoft-based. Also on Tuesday, Apple released a bevy of security updates to iOS, iPadOS, macOS, tvOS and Safari, including a patch for a newly discovered zero-day vulnerability that could lead to remote code execution.
Anyone responsible for maintaining Fortinet or Citrix remote access products probably needs to update, as both are dealing with active attacks on just-patched flaws.
For a closer look at the patches released by Microsoft today (indexed by severity and other metrics) check out the always-useful Patch Tuesday roundup from the SANS Internet Storm Center. And it’s not a bad idea to hold off updating for a few days until Microsoft works out any kinks in the updates: AskWoody.com usually has the lowdown on any patches that may be causing problems for Windows users.
As always, please consider backing up your system or at least your important documents and data before applying system updates. And if you run into any problems with these updates, please drop a note about it here in the comments.
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Let’s face it: Having “2022 election” in the headline above is probably the only reason anyone might read this story today. Still, while most of us here in the United States are anxiously awaiting the results of how well we’ve patched our Democracy, it seems fitting that Microsoft Corp. today released gobs of security patches for its ubiquitous Windows operating systems. November’s patch batch includes fixes for a whopping six zero-day security vulnerabilities that miscreants and malware are already exploiting in the wild.
Probably the scariest of the zero-day flaws is CVE-2022-41128, a “critical” weakness in the Windows scripting languages that could be used to foist malicious software on vulnerable users who do nothing more than browse to a hacked or malicious site that exploits the weakness. Microsoft credits Google with reporting the vulnerability, which earned a CVSS score of 8.8.
CVE-2022-41073 is a zero-day flaw in the Windows Print Spooler, a Windows component that Microsoft has patched mightily over the past year. Kevin Breen, director of cyber threat research at Immersive Labs, noted that the print spooler has been a popular target for vulnerabilities in the last 12 months, with this marking the 9th patch.
The third zero-day Microsoft patched this month is CVE-2022-41125, which is an “elevation of privilege” vulnerability in the Windows Cryptography API: Next Generation (CNG) Key Isolation Service, a service for isolating private keys. Satnam Narang, senior staff research engineer at Tenable, said exploitation of this vulnerability could grant an attacker SYSTEM privileges.
The fourth zero-day, CVE-2022-41091, was previously disclosed and widely reported on in October. It is a Security Feature Bypass of “Windows Mark of the Web” – a mechanism meant to flag files that have come from an untrusted source.
The other two zero-day bugs Microsoft patched this month were for vulnerabilities being exploited in Exchange Server. News that these two Exchange flaws were being exploited in the wild surfaced in late September 2022, and many were surprised when Microsoft let October’s Patch Tuesday sail by without issuing official patches for them (the company instead issued mitigation instructions that it was forced to revise multiple times). Today’s patch batch addresses both issues.
Greg Wiseman, product manager at Rapid7, said the Exchange flaw CVE-2022-41040 is a “critical” elevation of privilege vulnerability, and CVE-2022-41082 is considered Important, allowing Remote Code Execution (RCE) when PowerShell is accessible to the attacker.
“Both vulnerabilities have been exploited in the wild,” Wiseman said. “Four other CVEs affecting Exchange Server have also been addressed this month. Three are rated as Important, and CVE-2022-41080 is another privilege escalation vulnerability considered Critical. Customers are advised to update their Exchange Server systems immediately, regardless of whether any previously recommended mitigation steps have been applied. The mitigation rules are no longer recommended once systems have been patched.”
Adobe usually issues security updates for its products on Patch Tuesday, but it did not this month. For a closer look at the patches released by Microsoft today and indexed by severity and other metrics, check out the always-useful Patch Tuesday roundup from the SANS Internet Storm Center. And it’s not a bad idea to hold off updating for a few days until Microsoft works out any kinks in the updates: AskWoody.com usually has the lowdown on any patches that may be causing problems for Windows users.
As always, please consider backing up your system or at least your important documents and data before applying system updates. And if you run into any problems with these updates, please drop a note about it here in the comments.
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Microsoft today released updates to fix at least 85 security holes in its Windows operating systems and related software, including a new zero-day vulnerability in all supported versions of Windows that is being actively exploited. However, noticeably absent from this month’s Patch Tuesday are any updates to address a pair of zero-day flaws being exploited this past month in Microsoft Exchange Server.
The new zero-day flaw– CVE-2022-41033 — is an “elevation of privilege” bug in the Windows COM+ event service, which provides system notifications when users logon or logoff. Microsoft says the flaw is being actively exploited, and that it was reported by an anonymous individual.
“Despite its relatively low score in comparison to other vulnerabilities patched today, this one should be at the top of everyone’s list to quickly patch,” said Kevin Breen, director of cyber threat research at Immersive Labs. “This specific vulnerability is a local privilege escalation, which means that an attacker would already need to have code execution on a host to use this exploit. Privilege escalation vulnerabilities are a common occurrence in almost every security compromise. Attackers will seek to gain SYSTEM or domain-level access in order to disable security tools, grab credentials with tools like Mimkatz and move laterally across the network.
Indeed, Satnam Narang, senior staff research engineer at Tenable, notes that almost half of the security flaws Microsoft patched this week are elevation of privilege bugs.
Some privilege escalation bugs can be particularly scary. One example is CVE-2022-37968, which affects organizations running Kubernetes clusters on Azure and earned a CVSS score of 10.0 — the most severe score possible.
Microsoft says that to exploit this vulnerability an attacker would need to know the randomly generated DNS endpoint for an Azure Arc-enabled Kubernetes cluster. But that may not be such a tall order, says Breen, who notes that a number of free and commercial DNS discovery services now make it easy to find this information on potential targets.
Late last month, Microsoft acknowledged that attackers were exploiting two previously unknown vulnerabilities in Exchange Server. Paired together, the two flaws are known as “ProxyNotShell” and they can be chained to allow remote code execution on Exchange Server systems.
Microsoft said it was expediting work on official patches for the Exchange bugs, and it urged affected customers to enable certain settings to mitigate the threat from the attacks. However, those mitigation steps were soon shown to be ineffective, and Microsoft has been adjusting them on a daily basis nearly each day since then.
The lack of Exchange patches leaves a lot of Microsoft customers exposed. Security firm Rapid7 said that as of early September 2022 the company observed more than 190,000 potentially vulnerable instances of Exchange Server exposed to the Internet.
“While Microsoft confirmed the zero-days and issued guidance faster than they have in the past, there are still no patches nearly two weeks out from initial disclosure,” said Caitlin Condon, senior manager of vulnerability research at Rapid7. “Despite high hopes that today’s Patch Tuesday release would contain fixes for the vulnerabilities, Exchange Server is conspicuously missing from the initial list of October 2022 security updates. Microsoft’s recommended rule for blocking known attack patterns has been bypassed multiple times, emphasizing the necessity of a true fix.”
Adobe also released security updates to fix 29 vulnerabilities across a variety of products, including Acrobat and Reader, ColdFusion, Commerce and Magento. Adobe said it is not aware of active attacks against any of these flaws.
For a closer look at the patches released by Microsoft today and indexed by severity and other metrics, check out the always-useful Patch Tuesday roundup from the SANS Internet Storm Center. And it’s not a bad idea to hold off updating for a few days until Microsoft works out any kinks in the updates: AskWoody.com usually has the lowdown on any patches that may be causing problems for Windows users.
As always, please consider backing up your system or at least your important documents and data before applying system updates. And if you run into any problems with these updates, please drop a note about it here in the comments.
Microsoft Corp. is investigating reports that attackers are exploiting two previously unknown vulnerabilities in Exchange Server, a technology many organizations rely on to send and receive email. Microsoft says it is expediting work on software patches to plug the security holes. In the meantime, it is urging a subset of Exchange customers to enable a setting that could help mitigate ongoing attacks.
In customer guidance released Thursday, Microsoft said it is investigating two reported zero-day flaws affecting Microsoft Exchange Server 2013, 2016, and 2019. CVE-2022-41040, is a Server-Side Request Forgery (SSRF) vulnerability that can enable an authenticated attacker to remotely trigger the second zero-day vulnerability — CVE-2022-41082 — which allows remote code execution (RCE) when PowerShell is accessible to the attacker.
Microsoft said Exchange Online has detections and mitigation in place to protect customers. Customers using on-premises Microsoft Exchange servers are urged to review the mitigations suggested in the security advisory, which Microsoft says should block the known attack patterns.
Vietnamese security firm GTSC on Thursday published a writeup on the two Exchange zero-day flaws, saying it first observed the attacks in early August being used to drop “webshells.” These web-based backdoors offer attackers an easy-to-use, password-protected hacking tool that can be accessed over the Internet from any browser.
“We detected webshells, mostly obfuscated, being dropped to Exchange servers,” GTSC wrote. “Using the user-agent, we detected that the attacker uses Antsword, an active Chinese-based opensource cross-platform website administration tool that supports webshell management. We suspect that these come from a Chinese attack group because the webshell codepage is 936, which is a Microsoft character encoding for simplified Chinese.”
GTSC’s advisory includes details about post-compromise activity and related malware, as well as steps it took to help customers respond to active compromises of their Exchange Server environment. But the company said it would withhold more technical details of the vulnerabilities for now.
In March 2021, hundreds of thousands of organizations worldwide had their email stolen and multiple backdoor webshells installed, all thanks to four zero-day vulnerabilities in Exchange Server.
Granted, the zero-day flaws that powered that debacle were far more critical than the two detailed this week, and there are no signs yet that exploit code has been publicly released (that will likely change soon). But part of what made last year’s Exchange Server mass hack so pervasive was that vulnerable organizations had little or no advance notice on what to look for before their Exchange Server environments were completely owned by multiple attackers.
Microsoft is quick to point out that these zero-day flaws require an attacker to have a valid username and password for an Exchange user, but this may not be such a tall order for the hackers behind these latest exploits against Exchange Server.
Steven Adair is president of Volexity, the Virginia-based cybersecurity firm that was among the first to sound the alarm about the Exchange zero-days targeted in the 2021 mass hack. Adair said GTSC’s writeup includes an Internet address used by the attackers that Volexity has tied with high confidence to a China-based hacking group that has recently been observed phishing Exchange users for their credentials.
In February 2022, Volexity warned that this same Chinese hacking group was behind the mass exploitation of a zero-day vulnerability in the Zimbra Collaboration Suite, which is a competitor to Microsoft Exchange that many enterprises use to manage email and other forms of messaging.
If your organization runs Exchange Server, please consider reviewing the Microsoft mitigations and the GTSC post-mortem on their investigations.
Explore the nature of vulnerabilities in this episode of ThreatWise TV.
It’s shaping up to be another big year for vulnerability disclosure. Already the number of Common Vulnerabilities and Exposures (CVEs) disclosed has crossed 18,000 and it’s on track to make this another record-breaking year.
With new CVEs being disclosed daily, it has become increasingly difficult for security teams to stay abreast of the latest risks, let alone quickly determine which ones apply to their network environment. From those, prioritizing which CVEs to patch first adds an additional wrinkle to the process.
If this wasn’t challenging enough, a curve ball that’s often lobbed at security teams are the “breaking news” vulnerabilities— vulnerabilities picked up by the security media, often with much fanfare. The stories surrounding these high-profile vulnerabilities generally carry an implied threat that the CVE in question will throw the doors wide open to attackers if not addressed immediately. What security team hasn’t had someone from the C-suite share an article they’ve read, asking “are we protected from this?”
On the surface, CVEs that appear severe enough to garner media attention do seem like a good place to start when addressing vulnerabilities in your environment. But vulnerabilities are complicated, and what a security researcher manages to do within a controlled environment doesn’t always translate into real-world attacks. In fact, most disclosed vulnerabilities never see active exploitation. And of those that do, not every vulnerability ends up becoming a tool in an attacker’s arsenal. Bad actors generally follow the path of least resistance when they compromise a network, relying on tested exploits long before trying something new and unproven.
This begs the question: how much overlap is there between the most talked about vulnerabilities and those that are widely used in attacks? Moreover, if media attention isn’t a reliable indicator, what else might predict if a vulnerability will be used in an attack?
To answer these questions, we used intelligence tools available from Cisco’s Kenna Security risk-based vulnerability management (RBVM) software. In particular, Kenna.VI+ consolidates a variety of vulnerability intelligence, where a CVE ID lookup can pull back a wealth of information. In addition to this, Kenna.VI+ includes an API that brings in an additional layer of external threat intelligence, enabling further analysis.
We started with a direct comparison of Successful Exploitations and Chatter Count from within Kenna.VI+. The former is a full count of confirmed exploits within the dataset, while the latter is a count of mentions in the news, social media, various forums, and the dark web.
Our first pass at the data included a comparison of the top 50 CVEs in both Successful Exploitations and Chatter Count. However, there were only two CVEs that overlapped. The data showed that many of the top exploited CVEs were old and predated the data in Chatter Count. We quickly decided that this wasn’t a fair comparison.
To get a better look at more relevant CVEs, we limited the dataset to a range of 10 years. Unfortunately, this did not do much to improve things—only three CVEs showed up in both lists.
A more effective approach was to look at CVEs that we know are actively being exploited. The Cybersecurity and Infrastructure Security Agency (CISA) happens to maintain such a list. The Known Exploited Vulnerabilities (KEV) catalog is considered an authoritative compilation of vulnerabilities identified as being actively exploited in the wild.
Running the KEV catalog though Kenna.VI+ resulted in six CVEs that appeared in the top 50 for both lists, with a single overlap in the top 10. This leads us to conclude that the vulnerabilities with the most discussion are not the same as those being actively exploited in the majority of cases.
| CVE | Brief description | |
| 1 | CVE-2017-9841 | PHPUnit vulnerability (used to target popular CMSes) |
| 2 | CVE-2021-44228 | Log4j vulnerability |
| 3 | CVE-2019-0703 | Windows SMB information disclosure vulnerability |
| 4 | CVE-2014-0160 | Heartbleed vulnerability |
| 5 | CVE-2017-9805 | REST plugin in Apache Struts vulnerability |
| 6 | CVE-2017-11882 | Microsoft Office memory corruption vulnerability |
| 7 | CVE-2017-5638 | Apache Struts vulnerability (used in Equifax breach) |
| 8 | CVE-2012-1823 | 10-year-old PHP vulnerability |
| 9 | CVE-2017-0144 | EternalBlue vulnerability |
| 10 | CVE-2018-11776 | Apache Struts RCE vulnerability |
| CVE | Brief description | |
| 1 | CVE-2021-26855 | Microsoft Exchange vulnerability (used in Hafnium attacks) |
| 2 | CVE-2021-40444 | Microsoft MSHTML RCE vulnerability |
| 3 | CVE-2021-26084 | Confluence Server and Data Center vulnerability |
| 4 | CVE-2021-27065 | Microsoft Exchange vulnerability (used in Hafnium attacks) |
| 5 | CVE-2021-34473 | Microsoft Exchange vulnerability (used in Hafnium attacks) |
| 6 | CVE-2021-26858 | Microsoft Exchange vulnerability (used in Hafnium attacks) |
| 7 | CVE-2021-44228 | Log4j vulnerability |
| 8 | CVE-2021-34527 | One of the PrintNightmare vulnerabilities |
| 9 | CVE-2021-41773 | Apache HTTP Server vulnerability |
| 10 | CVE-2021-31207 | One of the ProxyShell vulnerabilities |
Despite the lack of overlap, there are many well-known vulnerabilities at the top of both lists. Heartbleed and EternalBlue appear on the top 10 exploited list, while Hafnium, PrintNightmare, and ProxyShell make the top 10 most talked about CVEs.
The Log4j vulnerability is the only CVE that appears in both lists. This isn’t surprising considering the ubiquity of Log4j in modern software. It’s the second-most exploited vulnerability—far outpacing the CVEs directly below it. This, coupled with its appearance in the chatter list, puts it in a class of its own. In a brief period, it’s managed to outpace older CVEs that are arguably just as well known.
The CVE that recorded the most successful exploitations is a five-year-old vulnerability in PHPUnit. This is a popular unit-testing framework that’s used by many CMSes, such as Drupal, WordPress, MediaWiki, and Moodle.
Since many websites are built with these tools, this exploit can be a handy vector for gaining initial access to unpatched webservers. This also lines up with research we conducted last year, where this vulnerability was one of the most common Snort detections seen by Cisco Secure Firewall.
All four of the Microsoft Exchange Server vulnerabilities used in the Hafnium attacks appear in the most talked about list of CVEs. However, even when you add all four of these CVEs together, they still don’t come anywhere close to the counts seen in the top exploited CVEs.
If media attention is not a good predictor of use for exploitation, then what are the alternatives?
The Common Vulnerability Scoring System (CVSS) is a well-known framework for gauging the severity of vulnerabilities. We looked for CVEs from the KEV catalog that were ranked as “critical”—9.0 and above in the CVSSv3 specification. Examining the entire KEV catalog, 28% of the CVEs have a score of 9.0 or higher. Of the top 50 successfully exploited, 38% had such scores.
This is an improvement, but the CVSSv3 specification was released in 2015. Many CVEs in the KEV catalog predate this—19% of the entire catalog and 28% of the top 50—and have no score.
Using the previous CVSS specification does fill this gap—36% overall and 52% of the top 50 score 9.0 or higher. However, the older CVSS specification comes with its share of issues as well.
Another indicator worth exploring is remote control execution (RCE). A vulnerability with RCE grants an attacker the ability to access and control a vulnerable system from anywhere. It turns out that 45% of the CVEs in our dataset allow for RCE, and 66% of the top 50, making it the most worthwhile indicator analyzed.
Let’s summarize how we’ve honed our approach to determine if media attention and exploitation line up:
| Data set | Exploitation and Chatter lists | Number of CVEs |
| All CVEs | Appears in both top 50 | 2 |
| Appears in both top 50 (last 10 years) | 3 | |
| KEV Catalog | Appears in both top 50 | 6 |
| Appears in both top 10 | 1 |
And here’s a summary of our look at other indicators:
| KEV Catalog | Top 50 exploited | |
| CVSSv3 (9.0+) | 28% | 38% |
| CVSS (9.0+) | 36% | 52% |
| Allows for RCE | 45% | 66% |
All of this analysis provides a clear answer to our original question—the most regularly exploited CVEs aren’t the most talked about. Additional work highlights that monitoring variables like RCE can help with prioritization.
For illustrative purposes we’ve only looked at a few indicators that could be used to prioritize CVEs. While some did better than others, we don’t recommend relying on a single variable in making decisions about vulnerability management. Creating an approach that folds in multiple indicators is a far better strategy when it comes to real-world application of this data. And while our findings here speak to the larger picture, every network is different.
Regardless of which list they appear on, be it Successful Exploitations or Chatter Count, it’s important to point out that all these vulnerabilities are serious. Just because Hafnium has more talk than Heartbleed doesn’t make it any less dangerous if you have assets that are vulnerable to it. The fact is that while CVEs with more talk didn’t make the top of the exploitation list, they still managed to rack up tens of thousands of successful exploitations.
It’s important to know how to prioritize security updates, fixing those that expose you to the most risk as soon as possible. From our perspective, here are some basic elements in the Cisco Secure portfolio that can help.
Kenna Security, a pioneer in risk-based vulnerability management, relies on threat intel and prioritization to keep security and IT teams focused on risks. Using data science, Kenna processes and analyzes 18+ threat and exploit intelligence feeds, and 12.7+ billion managed vulnerabilities to give you an accurate view of your company’s risk. With our risk scoring and remediation intelligence, you get the info you need to make truly data-driven remediation decisions.
To responsibly protect a network, it’s important to monitor all assets that connect to it and ensure they’re kept up to date. Duo Device Trust can check the patch level of devices for you before they’re granted access to connect to corporate applications or sensitive data. You can even block access and enable self-remediation for devices that are found to be non-compliant.
How about remote workers? By leveraging the Network Visibility Module in Cisco Secure Client as a telemetry source, Cisco Secure Cloud Analytics can capture endpoint-specific user and device context to supply visibility into remote worker endpoint status. This can bolster an organization’s security posture by providing visibility on remote employees that are running software versions with vulnerabilities that need patching.
Lastly, for some “lateral thinking” about vulnerability management, take a look at this short video of one of our Advisory CISOs, Wolfgang Goerlich. Especially if you’re a fan of the music of the 1920s…
We’d love to hear what you think. Ask a Question, Comment Below, and Stay Connected with Cisco Secure on social!
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