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Microsoft Raises Alert for Under-Attack Windows Flaw

Microsoft on Tuesday warned that its security teams have detected zero-day exploitation of a critical vulnerability in its flagship Windows platform.

Redmond included a fix for the latest zero-day in the September batch of Patch Tuesday updates and warned that attackers are already exploiting the flaw to gain SYSTEM privileges on fully patched Windows machines.

Microsoft released a barebones bulletin acknowledging the bug exists in Windows Common Log File System (CLFS), a subsystem used for data and event logging.

From the bulletin:

“An attacker who successfully exploited this vulnerability could gain SYSTEM privileges. An attacker must already have access and the ability to run code on the target system. This technique does not allow for remote code execution in cases where the attacker does not already have that ability on the target system.”

The vulnerability, tracked as CVE-2022-37969, was reported to Microsoft by four different organizations, suggesting it was used in an exploit chain linked to limited, targeted attacks.

Microsoft did not release any technical details on the bug or any indicators of compromise (IOCs) to help defenders hunt for signs of infection.  

[ READ: Adobe Patches 63 Security Flaws in Patch Tuesday Bundle ]

The already-exploited CLFS flaw carries a CVSS score of 7.8 out of 10.

The Microsoft Patch Tuesday releases cover at least 64 new vulnerabilities in a wide range of Windows and OS components, including remote code execution flaws in Dynamics CRM, SharePoint,  Office and Office Components, Windows Defender and the Chromium-based Microsoft Edge.

According to ZDI, The Trend Micro unit that closely tracks vulnerability warnings, Windows admins should pay urgent attention to these additional issues:

CVE-2022-34718 -- Windows TCP/IP Remote Code Execution Vulnerability -- This Critical-rated bug could allow a remote, unauthenticated attacker to execute code with elevated privileges on affected systems without user interaction. That officially puts it into the “wormable” category and earns it a CVSS rating of 9.8. However, only systems with IPv6 enabled and IPSec configured are vulnerable. While good news for some, if you’re using IPv6 (as many are), you’re probably running IPSec as well. Definitely test and deploy this update quickly.

CVE-2022-34724 -- Windows DNS Server Denial of Service Vulnerability -- This bug is only rated Important since there’s no chance of code execution, but you should probably treat it as Critical due to its potential impact. A remote, unauthenticated attacker could create a denial-of-service (DoS) condition on your DNS server. It’s not clear if the DoS just kills the DNS service or the whole system. Shutting down DNS is always bad, but with so many resources in the cloud, a loss of DNS pointing the way to those resources could be catastrophic for many enterprises.

CVE-2022-3075 -- Chromium: CVE-2022-3075 Insufficient data validation in Mojo -- This patch was released by the Google Chrome team back on September 2, so this is more of an “in case you missed it.” This vulnerability allows code execution on affected Chromium-based browsers (like Edge) and has been detected in the wild. This is the sixth Chrome exploit detected in the wild this year. The trend shows the near-ubiquitous browser platform has become a popular target for attackers. Make sure to update all of your systems based on Chromium.

In addition to Microsoft, software maker Adobe also rolled out security fixes for at least 63 security vulnerabilities in a wide range of widely deployed Windows and macOS software products

As part of the scheduled September batch of Patch Tuesday updates, Adobe called attention to critical-rated bulletins affecting the Adobe Bridge, InDesign, Photoshop, InCopy, Animage and Illustrator software products. 

Adobe said it was not aware of any exploits in the wild for any of the patched vulnerabilities.

Related: Adobe Patches 63 Security Flaws in Patch Tuesday Bundle

Related: ICS Patch Tuesday: Siemens, Schneider Electric Fix High-Severity Flaws

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Ryan Naraine is Editor-at-Large at SecurityWeek and host of the popular Security Conversations podcast series. Ryan is a veteran cybersecurity strategist who has built security engagement programs at major global brands, including Intel Corp., Bishop Fox and GReAT. He is a co-founder of Threatpost and the global SAS conference series. Ryan's past career as a security journalist included bylines at major technology publications including Ziff Davis eWEEK, CBS Interactive's ZDNet, PCMag and PC World. Ryan is a director of the Security Tinkerers non-profit, an advisor to early-stage entrepreneurs, and a regular speaker at security conferences around the world. Follow Ryan on Twitter @ryanaraine.