April’s Patch Tuesday Brings Record Number of Fixes

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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Microsoft Patch Tuesday, August 2022 Edition

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.

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