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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.
The victim shaming site operated by the Snatch ransomware group is leaking data about its true online location and internal operations, as well as the Internet addresses of its visitors, KrebsOnSecurity has found. The leaked data suggest that Snatch is one of several ransomware groups using paid ads on Google.com to trick people into installing malware disguised as popular free software, such as Microsoft Teams, Adobe Reader, Mozilla Thunderbird, and Discord.
First spotted in 2018, the Snatch ransomware group has published data stolen from hundreds of organizations that refused to pay a ransom demand. Snatch publishes its stolen data at a website on the open Internet, and that content is mirrored on the Snatch team’s darknet site, which is only reachable using the global anonymity network Tor.
The victim shaming website for the Snatch ransomware gang.
KrebsOnSecurity has learned that Snatch’s darknet site exposes its “server status” page, which includes information about the true Internet addresses of users accessing the website.
Refreshing this page every few seconds shows that the Snatch darknet site generates a decent amount of traffic, often attracting thousands of visitors each day. But by far the most frequent repeat visitors are coming from Internet addresses in Russia that either currently host Snatch’s clear web domain names or recently did.
The Snatch ransomware gang’s victim shaming site on the darknet is leaking data about its visitors. This “server status” page says that Snatch’s website is on Central European Summer Time (CEST) and is powered by OpenSSL/1.1.1f, which is no longer supported by security updates.
Probably the most active Internet address accessing Snatch’s darknet site is 193.108.114[.]41, which is a server in Yekaterinburg, Russia that hosts several Snatch domains, including snatchteam[.]top, sntech2ch[.]top, dwhyj2[.]top and sn76930193ch[.]top. It could well be that this Internet address is showing up frequently because Snatch’s clear-web site features a toggle button at the top that lets visitors switch over to accessing the site via Tor.
Another Internet address that showed up frequently in the Snatch server status page was 194.168.175[.]226, currently assigned to Matrix Telekom in Russia. According to DomainTools.com, this address also hosts or else recently hosted the usual coterie of Snatch domains, as well as quite a few domains phishing known brands such as Amazon and Cashapp.
The Moscow Internet address 80.66.64[.]15 accessed the Snatch darknet site all day long, and that address also housed the appropriate Snatch clear-web domains. More interestingly, that address is home to multiple recent domains that appear confusingly similar to known software companies, including libreoff1ce[.]com and www-discord[.]com.
This is interesting because the phishing domains associated with the Snatch ransomware gang were all registered to the same Russian name — Mihail Kolesnikov, a name that is somewhat synonymous with recent phishing domains tied to malicious Google ads.
Kolesnikov could be a nod to a Russian general made famous during Boris Yeltsin’s reign. Either way, it’s clearly a pseudonym, but there are some other commonalities among these domains that may provide insight into how Snatch and other ransomware groups are sourcing their victims.
DomainTools says there are more than 1,300 current and former domain names registered to Mihail Kolesnikov between 2013 and July 2023. About half of the domains appear to be older websites advertising female escort services in major cities around the United States (e.g. the now-defunct pittsburghcitygirls[.]com).
The other half of the Kolesnikov websites are far more recent phishing domains mostly ending in “.top” and “.app” that appear designed to mimic the domains of major software companies, including www-citrix[.]top, www-microsofteams[.]top, www-fortinet[.]top, ibreoffice[.]top, www-docker[.]top, www-basecamp[.]top, ccleaner-cdn[.]top, adobeusa[.]top, and www.real-vnc[.]top.
In August 2023, researchers with Trustwave Spiderlabs said they encountered domains registered to Mihail Kolesnikov being used to disseminate the Rilide information stealer trojan.
But it appears multiple crime groups may be using these domains to phish people and disseminate all kinds of information-stealing malware. In February 2023, Spamhaus warned of a huge surge in malicious ads that were hijacking search results in Google.com, and being used to distribute at least five different families of information stealing trojans, including AuroraStealer, IcedID/Bokbot, Meta Stealer, RedLine Stealer and Vidar.
For example, Spamhaus said victims of these malicious ads would search for Microsoft Teams in Google.com, and the search engine would often return a paid ad spoofing Microsoft or Microsoft Teams as the first result — above all other results. The malicious ad would include a logo for Microsoft and at first glance appear to be a safe and trusted place to download the Microsoft Teams client.
However, anyone who clicked on the result was whisked away instead to mlcrosofteams-us[.]top — yet another malicious domain registered to Mr. Kolesnikov. And while visitors to this website may believe they are only downloading the Microsoft Teams client, the installer file includes a copy of the IcedID malware, which is really good at stealing passwords and authentication tokens from the victim’s web browser.
Image: Spamhaus
The founder of the Swiss anti-abuse website abuse.ch told Spamhaus it is likely that some cybercriminals have started to sell “malvertising as a service” on the dark web, and that there is a great deal of demand for this service.
In other words, someone appears to have built a very profitable business churning out and promoting new software-themed phishing domains and selling that as a service to other cybercriminals. Or perhaps they are simply selling any stolen data (and any corporate access) to active and hungry ransomware group affiliates.
The tip about the exposed “server status” page on the Snatch darkweb site came from @htmalgae, the same security researcher who alerted KrebsOnSecurity earlier this month that the darknet victim shaming site run by the 8Base ransomware gang was inadvertently left in development mode.
That oversight revealed not only the true Internet address of the hidden 8Base site (in Russia, naturally), but also the identity of a programmer in Moldova who apparently helped to develop the 8Base code.
@htmalgae said the idea of a ransomware group’s victim shaming site leaking data that they did not intend to expose is deliciously ironic.
“This is a criminal group that shames others for not protecting user data,” @htmalgae said. “And here they are leaking their user data.”
All of the malware mentioned in this story is designed to run on Microsoft Windows devices. But Malwarebytes recently covered the emergence of a Mac-based information stealer trojan called AtomicStealer that was being advertised through malicious Google ads and domains that were confusingly similar to software brands.
Please be extra careful when you are searching online for popular software titles. Cracked, pirated copies of major software titles are a frequent source of infostealer infections, as are these rogue ads masquerading as search results. Make sure to double-check you are actually at the domain you believe you’re visiting *before* you download and install anything.
Stay tuned for Part II of this post, which includes a closer look at the Snatch ransomware group and their founder.
Further reading:
@HTMalgae’s list of the top Internet addresses seen accessing Snatch’s darknet site
Ars Technica: Until Further Notice Think Twice Before Using Google to Download Software
Bleeping Computer: Hackers Abuse Google Ads to Spread Malware in Legit Software
In December 2022, KrebsOnSecurity broke the news that a cybercriminal using the handle “USDoD” had infiltrated the FBI‘s vetted information sharing network InfraGard, and was selling the contact information for all 80,000 members. The FBI responded by reverifying InfraGard members and by seizing the cybercrime forum where the data was being sold. But on Sept. 11, 2023, USDoD resurfaced after a lengthy absence to leak sensitive employee data stolen from the aerospace giant Airbus, while promising to visit the same treatment on top U.S. defense contractors.
USDoD’s avatar used to be the seal of the U.S. Department of Defense. Now it’s a charming kitten.
In a post on the English language cybercrime forum BreachForums, USDoD leaked information on roughly 3,200 Airbus vendors, including names, addresses, phone numbers, and email addresses. USDoD claimed they grabbed the data by using passwords stolen from a Turkish airline employee who had third-party access to Airbus’ systems.
USDoD didn’t say why they decided to leak the data on the 22nd anniversary of the 9/11 attacks, but there was definitely an aircraft theme to the message that accompanied the leak, which concluded with the words, “Lockheed martin, Raytheon and the entire defense contractos [sic], I’m coming for you [expletive].”
Airbus has apparently confirmed the cybercriminal’s account to the threat intelligence firm Hudson Rock, which determined that the Airbus credentials were stolen after a Turkish airline employee infected their computer with a prevalent and powerful info-stealing trojan called RedLine.
Info-stealers like RedLine typically are deployed via opportunistic email malware campaigns, and by secretly bundling the trojans with cracked versions of popular software titles made available online. Credentials stolen by info-stealers often end up for sale on cybercrime shops that peddle purloined passwords and authentication cookies (these logs also often show up in the malware scanning service VirusTotal).
Hudson Rock said it recovered the log files created by a RedLine infection on the Turkish airline employee’s system, and found the employee likely infected their machine after downloading pirated and secretly backdoored software for Microsoft Windows.
Hudson Rock says info-stealer infections from RedLine and a host of similar trojans have surged in recent years, and that they remain “a primary initial attack vector used by threat actors to infiltrate organizations and execute cyberattacks, including ransomware, data breaches, account overtakes, and corporate espionage.”
The prevalence of RedLine and other info-stealers means that a great many consequential security breaches begin with cybercriminals abusing stolen employee credentials. In this scenario, the attacker temporarily assumes the identity and online privileges assigned to a hacked employee, and the onus is on the employer to tell the difference.
In addition to snarfing any passwords stored on or transmitted through an infected system, info-stealers also siphon authentication cookies or tokens that allow one to remain signed-in to online services for long periods of time without having to resupply one’s password and multi-factor authentication code. By stealing these tokens, attackers can often reuse them in their own web browser, and bypass any authentication normally required for that account.
Microsoft Corp. this week acknowledged that a China-backed hacking group was able to steal one of the keys to its email kingdom that granted near-unfettered access to U.S. government inboxes. Microsoft’s detailed post-mortem cum mea culpa explained that a secret signing key was stolen from an employee in an unlucky series of unfortunate events, and thanks to TechCrunch we now know that the culprit once again was “token-stealing malware” on the employee’s system.
In April 2023, the FBI seized Genesis Market, a bustling, fully automated cybercrime store that was continuously restocked with freshly hacked passwords and authentication tokens stolen by a network of contractors who deployed RedLine and other info-stealer malware.
In March 2023, the FBI arrested and charged the alleged administrator of BreachForums (aka Breached), the same cybercrime community where USDoD leaked the Airbus data. In June 2023, the FBI seized the BreachForums domain name, but the forum has since migrated to a new domain.
USDoD’s InfraGard sales thread on Breached.
Unsolicited email continues to be a huge vector for info-stealing malware, but lately the crooks behind these schemes have been gaming the search engines so that their malicious sites impersonating popular software vendors actually appear before the legitimate vendor’s website. So take special care when downloading software to ensure that you are in fact getting the program from the original, legitimate source whenever possible.
Also, unless you really know what you’re doing, please don’t download and install pirated software. Sure, the cracked program might do exactly what you expect it to do, but the chances are good that it is also laced with something nasty. And when all of your passwords are stolen and your important accounts have been hijacked or sold, you will wish you had simply paid for the real thing.
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.”
FreshRSS 