Category: Microsoft Office

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.

Microsoft is sending the world a whole bunch of love today, in the form of patches to plug dozens of security holes in its Windows operating systems and other software. This year’s special Valentine’s Day Patch Tuesday includes fixes for a whopping three different “zero-day” vulnerabilities that are already being used in active attacks.

Microsoft’s security advisories are somewhat sparse with details about the zero-day bugs. Redmond flags CVE-2023-23376 as an “Important” elevation of privilege vulnerability in the Windows Common Log File System Driver, which is present in Windows 10 and 11 systems, as well as many server versions of Windows.

“Sadly, there’s just a little solid information about this privilege escalation,” said Dustin Childs, head of threat awareness at Trend Micro’s Zero Day Initiative. “Microsoft does note that the vulnerability would allow an attacker to exploit code as SYSTEM, which would allow them to completely take over a target. This is likely being chained with a remote code execution bug to spread malware or ransomware. Considering this was discovered by Microsoft’s Threat Intelligence Center, it could mean it was used by advanced threat actors. Either way, make sure you test and roll these fixes quickly.”

The zero-day CVE-2023-21715 is a weakness in Microsoft Office that Redmond describes as a “security feature bypass vulnerability.”

“Microsoft lists this as under active exploit, but they offer no info on how widespread these exploits may be,” Childs said. “Based on the write-up, it sounds more like a privilege escalation than a security feature bypass, but regardless, active attacks in a common enterprise application shouldn’t be ignored. It’s always alarming when a security feature is not just bypassed but exploited. Let’s hope the fix comprehensively addresses the problem.”

The third zero-day flaw already seeing exploitation is CVE-2023-21823, which is another elevation of privilege weakness — this one in the Microsoft Windows Graphic component. Researchers at cybersecurity forensics firm Mandiant were credited with reporting the bug.

Kevin Breen, director of cyber threat research at Immersive Labs, pointed out that the security bulletin for CVE-2023-21823 specifically calls out OneNote as being a vulnerable component for the vulnerability.

“In recent weeks, we have seen an increase in the use of OneNote files as part of targeted malware campaigns,” Breen said. “Patches for this are delivered via the app stores and not through the typical formats, so it’s important to double check your organization’s policies.”

Microsoft fixed another Office vulnerability in CVE-2023-21716, which is a Microsoft Word bug that can lead to remote code execution — even if a booby-trapped Word document is merely viewed in the preview pane of Microsoft Outlook. This security hole has a CVSS (severity) score of 9.8 out of a possible 10.

Microsoft also has more valentines for organizations that rely on Microsoft Exchange Server to handle email. Redmond patched three Exchange Server flaws (CVE-2023-21706, CVE-2023-21707, and CVE-2023-21529), all of which Microsoft says are remote code execution flaws that are likely to be exploited.

Microsoft said authentication is required to exploit these bugs, but then again threat groups that attack Exchange vulnerabilities also tend to phish targets for their Exchange credentials.

Microsoft isn’t alone in dropping fixes for scary, ill-described zero-day flaws. Apple on Feb. 13 released an update for iOS that resolves a zero-day vulnerability in Webkit, Apple’s open source browser engine. Johannes Ullrich at the SANS Internet Storm Center notes that in addition to the WebKit problem, Apple fixed a privilege escalation issue. Both flaws are fixed in iOS 16.3.1.

“This privilege escalation issue could be used to escape the browser sandbox and gain full system access after executing code via the WebKit vulnerability,” Ullrich warned.

On a lighter note (hopefully), Microsoft drove the final nail in the coffin for Internet Explorer 11 (IE11). According to Redmond, the out-of-support IE11 desktop application was permanently disabled on certain versions of Windows 10 on February 14, 2023 through a Microsoft Edge update.

“All remaining consumer and commercial devices that were not already redirected from IE11 to Microsoft Edge were redirected with the Microsoft Edge update. Users will be unable to reverse the change,” Microsoft explained. “Additionally, redirection from IE11 to Microsoft Edge will be included as part of all future Microsoft Edge updates. IE11 visual references, such as the IE11 icons on the Start Menu and taskbar, will be removed by the June 2023 Windows security update (“B” release) scheduled for June 13, 2023.”

For a more granular rundown on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.

Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.