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Fat Patch Tuesday, February 2024 Edition

By BrianKrebs

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.

Ivanti Vulnerability Exploited to Install 'DSLog' Backdoor on 670+ IT Infrastructures

By Newsroom
Threat actors are leveraging a recently disclosed security flaw impacting Ivanti Connect Secure, Policy Secure, and ZTA gateways to deploy a backdoor codenamed DSLog on susceptible devices. That's according to findings from Orange Cyberdefense, which said it observed the exploitation of CVE-2024-21893 within hours of the public release of the proof-the-concept (PoC) code. CVE

Recent SSRF Flaw in Ivanti VPN Products Undergoes Mass Exploitation

By Newsroom
A recently disclosed server-side request forgery (SSRF) vulnerability impacting Ivanti Connect Secure and Policy Secure products has come under mass exploitation. The Shadowserver Foundation said it observed exploitation attempts originating from more than 170 unique IP addresses that aim to establish a reverse shell, among others. The attacks exploit CVE-2024-21893 (CVSS

Experts Warn of Ransomware Hackers Exploiting Atlassian and Apache Flaws

By Newsroom
Multiple ransomware groups have begun to actively exploit recently disclosed flaws in Atlassian Confluence and Apache ActiveMQ. Cybersecurity firm Rapid7 said it observed the exploitation of CVE-2023-22518 and CVE-2023-22515 in multiple customer environments, some of which have been leveraged for the deployment of Cerber (aka C3RB3R) ransomware. Both vulnerabilities are critical, allowing threat

HelloKitty Ransomware Group Exploiting Apache ActiveMQ Vulnerability

By Newsroom
Cybersecurity researchers are warning of suspected exploitation of a recently disclosed critical security flaw in the Apache ActiveMQ open-source message broker service that could result in remote code execution. "In both instances, the adversary attempted to deploy ransomware binaries on target systems in an effort to ransom the victim organizations," cybersecurity firm Rapid7 disclosed in a

Patch Tuesday, October 2023 Edition

By BrianKrebs

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.

Alert: Juniper Firewalls, Openfire, and Apache RocketMQ Under Attack from New Exploits

By THN
Recently disclosed security flaws impacting Juniper firewalls, Openfire, and Apache RocketMQ servers have come under active exploitation in the wild, according to multiple reports. The Shadowserver Foundation said that it's "seeing exploitation attempts from multiple IPs for Juniper J-Web CVE-2023-36844 (& friends) targeting /webauth_operation.php endpoint," the same day a proof-of-concept (PoC)

Cybercriminals Exploiting WooCommerce Payments Plugin Flaw to Hijack Websites

By THN
Threat actors are actively exploiting a recently disclosed critical security flaw in the WooCommerce Payments WordPress plugin as part of a massive targeted campaign. The flaw, tracked as CVE-2023-28121 (CVSS score: 9.8), is a case of authentication bypass that enables unauthenticated attackers to impersonate arbitrary users and perform some actions as the impersonated user, including an

Apple & Microsoft Patch Tuesday, July 2023 Edition

By BrianKrebs

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.

Barracuda Urges Replacing — Not Patching — Its Email Security Gateways

By BrianKrebs

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.

Microsoft Patch Tuesday, May 2023 Edition

By BrianKrebs

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 Patch Tuesday, March 2023 Edition

By BrianKrebs

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 Patch Tuesday, December 2022 Edition

By BrianKrebs

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.

Microsoft Patch Tuesday, October 2022 Edition

By BrianKrebs

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 Patch Tuesday, August 2022 Edition

By BrianKrebs

Microsoft today released updates to fix a record 141 security vulnerabilities in its Windows operating systems and related software. Once again, Microsoft is patching a zero-day vulnerability in the Microsoft Support Diagnostics Tool (MSDT), a service built into Windows. Redmond also addressed multiple flaws in Exchange Server — including one that was disclosed publicly prior to today — and it is urging organizations that use Exchange for email to update as soon as possible and to enable additional protections.

In June, Microsoft patched a vulnerability in MSDT dubbed “Follina” that had been used in active attacks for at least three months prior. This latest MSDT bug — CVE-2022-34713 — is a remote code execution flaw that requires convincing a target to open a booby-trapped file, such as an Office document. Microsoft this month also issued a different patch for another MSDT flaw, tagged as CVE-2022-35743.

The publicly disclosed Exchange flaw is CVE-2022-30134, which is an information disclosure weakness. Microsoft also released fixes for three other Exchange flaws that rated a “critical” label, meaning they could be exploited remotely to compromise the system and with no help from users. Microsoft says addressing some of the Exchange vulnerabilities fixed this month requires administrators to enable Windows Extended protection on Exchange Servers. See Microsoft’s blog post on the Exchange Server updates for more details.

“If your organization runs local exchange servers, this trio of CVEs warrant an urgent patch,” said Kevin Breen, director of cyber threat research for Immerse Labs. “Exchanges can be treasure troves of information, making them valuable targets for attackers. With CVE-2022-24477, for example, an attacker can gain initial access to a user’s host and could take over the mailboxes for all exchange users, sending and reading emails and documents. For attackers focused on Business Email Compromise this kind of vulnerability can be extremely damaging.”

The other two critical Exchange bugs are tracked as CVE-2022-24516 and CVE-2022-21980. It’s difficult to believe it’s only been a little more than a year since malicious hackers worldwide pounced in a bevy of zero-day Exchange vulnerabilities to remotely compromise the email systems for hundreds of thousands of organizations running Exchange Server locally for email. That lingering catastrophe is reminder enough that critical Exchange bugs deserve immediate attention.

The SANS Internet Storm Center‘s rundown on Patch Tuesday warns that a critical remote code execution bug in the Windows Point-to-Point Protocol (CVE-2022-30133) could become “wormable” — a threat capable of spreading across a network without any user interaction.

“Another critical vulnerability worth mentioning is an elevation of privilege affecting Active Directory Domain Services (CVE-2022-34691),” SANS wrote. “According to the advisory, ‘An authenticated user could manipulate attributes on computer accounts they own or manage, and acquire a certificate from Active Directory Certificate Services that would allow elevation of privilege to System.’ A system is vulnerable only if Active Directory Certificate Services is running on the domain. The CVSS for this vulnerability is 8.8.”

Breen highlighted a set of four vulnerabilities in Visual Studio that earned Microsoft’s less-dire “important” rating but that nevertheless could be vitally important for the security of developer systems.

“Developers are empowered with access to API keys and deployment pipelines that, if compromised, could be significantly damaging to organizations,” he said. “So it’s no surprise they are often targeted by more advanced attackers. Patches for their tools should not be overlooked. We’re seeing a continued trend of supply-chain compromise too, making it vital that we ensure developers, and their tools, are kept up-to-date with the same rigor we apply to standard updates.”

Greg Wiseman, product manager at Rapid7, pointed to an interesting bug Microsoft patched in Windows Hello, the biometric authentication mechanism for Windows 10.  Microsoft notes that the successful exploitation of the weakness requires physical access to the target device, but would allow an attacker to bypass a facial recognition check.

Wiseman said despite the record number of vulnerability fixes from Redmond this month, the numbers are slightly less dire.

“20 CVEs affect their Chromium-based Edge browser and 34 affect Azure Site Recovery (up from 32 CVEs affecting that product last month),” Wiseman wrote. “As usual, OS-level updates will address a lot of these, but note that some extra configuration is required to fully protect Exchange Server this month.”

As it often does on Patch Tuesday, Adobe has also released security updates for many of its products, including Acrobat and Reader, Adobe Commerce and Magento Open Source. More details here.

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 Patch Tuesday, July 2022 Edition

By BrianKrebs

Microsoft today released updates to fix at least 86 security vulnerabilities in its Windows operating systems and other software, including a weakness in all supported versions of Windows that Microsoft warns is actively being exploited. The software giant also has made a controversial decision to put the brakes on a plan to block macros in Office documents downloaded from the Internet.

In February, security experts hailed Microsoft’s decision to block VBA macros in all documents downloaded from the Internet. The company said it would roll out the changes in stages between April and June 2022.

Macros have long been a trusted way for cybercrooks to trick people into running malicious code. Microsoft Office by default warns users that enabling macros in untrusted documents is a security risk, but those warnings can be easily disabled with the click of button. Under Microsoft’s plan, the new warnings provided no such way to enable the macros.

As Ars Technica veteran reporter Dan Goodin put it, “security professionals—some who have spent the past two decades watching clients and employees get infected with ransomware, wipers, and espionage with frustrating regularity—cheered the change.”

But last week, Microsoft abruptly changed course. As first reported by BleepingComputer, Redmond said it would roll back the changes based on feedback from users.

“While Microsoft has not shared the negative feedback that led to the rollback of this change, users have reported that they are unable to find the Unblock button to remove the Mark-of-the-Web from downloaded files, making it impossible to enable macros,” Bleeping’s Sergiu Gatlan wrote.

Microsoft later said the decision to roll back turning off macros by default was temporary, although it has not indicated when this important change might be made for good.

The zero-day Windows vulnerability already seeing active attacks is CVE-2022-22047, which is an elevation of privilege vulnerability in all supported versions of Windows. Trend Micro’s Zero Day Initiative notes that while this bug is listed as being under active attack, there’s no information from Microsoft on where or how widely it is being exploited.

“The vulnerability allows an attacker to execute code as SYSTEM, provided they can execute other code on the target,” ZDI’s Dustin Childs wrote. “Bugs of this type are typically paired with a code execution bug, usually a specially crafted Office or Adobe document, to take over a system. These attacks often rely on macros, which is why so many were disheartened to hear Microsoft’s delay in blocking all Office macros by default.”

Kevin Breen, director of cyber threat research at Immersive Labs, said CVE-2022-22047 is the kind of vulnerability that is typically seen abused after a target has already been compromised.

“Crucially, it allows the attacker to escalate their permissions from that of a normal user to the same permissions as the SYSTEM,” he said. “With this level of access, the attackers are able to disable local services such as Endpoint Detection and Security tools. With SYSTEM access they can also deploy tools like Mimikatz which can be used to recover even more admin and domain level accounts, spreading the threat quickly.”

After a brief reprieve from patching serious security problems in the Windows Print Spooler service, we are back to business as usual. July’s patch batch contains fixes for four separate elevation of privilege vulnerabilities in Windows Print Spooler, identified as CVE-2022-22022, CVE-2022-22041, CVE-2022-30206, and CVE-2022-30226. Experts at security firm Tenable note that these four flaws provide attackers with the ability to delete files or gain SYSTEM level privileges on a vulnerable system.

Roughly a third of the patches issued today involve weaknesses in Microsoft’s Azure Site Recovery offering. Other components seeing updates this month include Microsoft Defender for Endpoint; Microsoft Edge (Chromium-based); Office; Windows BitLocker; Windows Hyper-V; Skype for Business and Microsoft Lync; and Xbox.

Four of the flaws fixed this month address vulnerabilities Microsoft rates “critical,” meaning they could be used by malware or malcontents to assume remote control over unpatched Windows systems, usually without any help from users. CVE-2022-22029 and CVE-2022-22039 affect Network File System (NFS) servers, and CVE-2022-22038 affects the Remote Procedure Call (RPC) runtime.

“Although all three of these will be relatively tricky for attackers to exploit due to the amount of sustained data that needs to be transmitted, administrators should patch sooner rather than later,” said Greg Wiseman, product manager at Rapid7. “CVE-2022-30221 supposedly affects the Windows Graphics Component, though Microsoft’s FAQ indicates that exploitation requires users to access a malicious RDP server.”

Separately, Adobe today issued patches to address at least 27 vulnerabilities across multiple products, including Acrobat and Reader, Photoshop, RoboHelp, and Adobe Character Animator.

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.

Zyxel Releases Patch for Critical Firewall OS Command Injection Vulnerability

By Ravie Lakshmanan
Zyxel has moved to address a critical security vulnerability affecting Zyxel firewall devices that enables unauthenticated and remote attackers to gain arbitrary code execution. "A command injection vulnerability in the CGI program of some firewall versions could allow an attacker to modify specific files and then execute some OS commands on a vulnerable device," the company said in an advisory

Microsoft Patch Tuesday, May 2022 Edition

By BrianKrebs

Microsoft today released updates to fix at least 74 separate security problems in its Windows operating systems and related software. This month’s patch batch includes fixes for seven “critical” flaws, as well as a zero-day vulnerability that affects all supported versions of Windows.

By all accounts, the most urgent bug Microsoft addressed this month is CVE-2022-26925, a weakness in a central component of Windows security (the “Local Security Authority” process within Windows). CVE-2022-26925 was publicly disclosed prior to today, and Microsoft says it is now actively being exploited in the wild. The flaw affects Windows 7 through 10 and Windows Server 2008 through 2022.

Greg Wiseman, product manager for Rapid7, said Microsoft has rated this vulnerability as important and assigned it a CVSS (danger) score of 8.1 (10 being the worst), although Microsoft notes that the CVSS score can be as high as 9.8 in certain situations.

“This allows attackers to perform a man-in-the-middle attack to force domain controllers to authenticate to the attacker using NTLM authentication,” Wiseman said. “This is very bad news when used in conjunction with an NTLM relay attack, potentially leading to remote code execution. This bug affects all supported versions of Windows, but Domain Controllers should be patched on a priority basis before updating other servers.”

Wiseman said the most recent time Microsoft patched a similar vulnerability — last August in CVE-2021-36942 — it was also being exploited in the wild under the name “PetitPotam.”

“CVE-2021-36942 was so bad it made CISA’s catalog of Known Exploited Vulnerabilities,” Wiseman said.

Seven of the flaws fixed today earned Microsoft’s most-dire “critical” label, which it assigns to vulnerabilities that can be exploited by malware or miscreants to remotely compromise a vulnerable Windows system without any help from the user.

Among those is CVE-2022-26937, which carries a CVSS score of 9.8, and affects services using the Windows Network File System (NFS). Trend Micro’s Zero Day Initiative notes that this bug could allow remote, unauthenticated attackers to execute code in the context of the Network File System (NFS) service on affected systems.

“NFS isn’t on by default, but it’s prevalent in environment where Windows systems are mixed with other OSes such as Linux or Unix,” ZDI’s Dustin Childs wrote. “If this describes your environment, you should definitely test and deploy this patch quickly.”

Once again, this month’s Patch Tuesday is sponsored by Windows Print Spooler, a core Windows service that keeps spooling out the security hits. May’s patches include four fixes for Print Spooler, including two information disclosure and two elevation of privilege flaws.

“All of the flaws are rated as important, and two of the three are considered more likely to be exploited,” said Satnam Narang, staff research engineer at Tenable. “Windows Print Spooler continues to remain a valuable target for attackers since PrintNightmare was disclosed nearly a year ago. Elevation of Privilege flaws in particular should be carefully prioritized, as we’ve seen ransomware groups like Conti favor them as part of its playbook.”

Other Windows components that received patches this month include .NET and Visual Studio, Microsoft Edge (Chromium-based), Microsoft Exchange Server, Office, Windows Hyper-V, Windows Authentication Methods, BitLocker, Remote Desktop Client, and Windows Point-to-Point Tunneling Protocol.

Also today, Adobe issued five security bulletins to address at least 18 flaws in Adobe CloudFusion, Framemaker, InCopy, InDesign, and Adobe Character Animator. Adobe said it is not aware of any exploits in the wild for any of the issues addressed in today’s updates.

For a more granular 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 skinny 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 patches, please drop a note about it here in the comments.

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