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Microsoft Corp. today released updates to fix at least 79 security vulnerabilities in its Windows operating systems and related software, including multiple flaws that are already showing up in active attacks. Microsoft also corrected a critical bug that has caused some Windows 10 PCs to remain dangerously unpatched against actively exploited vulnerabilities for several months this year.
By far the most curious security weakness Microsoft disclosed today has the snappy name of CVE-2024-43491, which Microsoft says is a vulnerability that led to the rolling back of fixes for some vulnerabilities affecting “optional components” on certain Windows 10 systems produced in 2015. Those include Windows 10 systems that installed the monthly security update for Windows released in March 2024, or other updates released until August 2024.
Satnam Narang, senior staff research engineer at Tenable, said that while the phrase “exploitation detected” in a Microsoft advisory normally implies the flaw is being exploited by cybercriminals, it appears labeled this way with CVE-2024-43491 because the rollback of fixes reintroduced vulnerabilities that were previously know to be exploited.
“To correct this issue, users need to apply both the September 2024 Servicing Stack Update and the September 2024 Windows Security Updates,” Narang said.
Kev Breen, senior director of threat research at Immersive Labs, said the root cause of CVE-2024-43491 is that on specific versions of Windows 10, the build version numbers that are checked by the update service were not properly handled in the code.
“The notes from Microsoft say that the ‘build version numbers crossed into a range that triggered a code defect’,” Breen said. “The short version is that some versions of Windows 10 with optional components enabled was left in a vulnerable state.”
Zero Day #1 this month is CVE-2024-38226, and it concerns a weakness in Microsoft Publisher, a standalone application included in some versions of Microsoft Office. This flaw lets attackers bypass Microsoft’s “Mark of the Web,” a Windows security feature that marks files downloaded from the Internet as potentially unsafe.
Zero Day #2 is CVE-2024-38217, also a Mark of the Web bypass affecting Office. Both zero-day flaws rely on the target opening a booby-trapped Office file.
Security firm Rapid7 notes that CVE-2024-38217 has been publicly disclosed via an extensive write-up, with exploit code also available on GitHub.
According to Microsoft, CVE-2024-38014, an “elevation of privilege” bug in the Windows Installer, is also being actively exploited.
June’s coverage of Microsoft Patch Tuesday was titled “Recall Edition,” because the big news then was that Microsoft was facing a torrent of criticism from privacy and security experts over “Recall,” a new artificial intelligence (AI) feature of Redmond’s flagship Copilot+ PCs that constantly takes screenshots of whatever users are doing on their computers.
At the time, Microsoft responded by suggesting Recall would no longer be enabled by default. But last week, the software giant clarified that what it really meant was that the ability to disable Recall was a bug/feature in the preview version of Copilot+ that will not be available to Windows customers going forward. Translation: New versions of Windows are shipping with Recall deeply embedded in the operating system.
It’s pretty rich that Microsoft, which already collects an insane amount of information from its customers on a near constant basis, is calling the Recall removal feature a bug, while treating Recall as a desirable feature. Because from where I sit, Recall is a feature nobody asked for that turns Windows into a bug (of the surveillance variety).
When Redmond first responded to critics about Recall, they noted that Recall snapshots never leave the user’s system, and that even if attackers managed to hack a Copilot+ PC they would not be able to exfiltrate on-device Recall data.
But that claim rang hollow after former Microsoft threat analyst Kevin Beaumont detailed on his blog how any user on the system (even a non-administrator) can export Recall data, which is just stored in an SQLite database locally.
As it is apt to do on Microsoft Patch Tuesday, Adobe has released updates to fix security vulnerabilities in a range of products, including Reader and Acrobat, After Effects, Premiere Pro, Illustrator, ColdFusion, Adobe Audition, and Photoshop. Adobe says it is not aware of any exploits in the wild for any of the issues addressed in its updates.
Seeking a more detailed breakdown of the patches released by Microsoft today? Check out the SANS Internet Storm Center’s thorough list. People responsible for administering many systems in an enterprise environment would do well to keep an eye on AskWoody.com, which often has the skinny on any wonky Windows patches that may be causing problems for some users.
As always, if you experience any issues applying this month’s patch batch, consider dropping a note in the comments here about it.
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.
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