Microsoft August 2023 Patch Tuesday warns of 2 zero-days, 87 flaws – Source: www.bleepingcomputer.com

ADV230003 – Microsoft Office Defense in Depth Update (publicly disclosed)

Microsoft has released an Office Defense in Depth update to fix a patch bypass of the previously fixed and actively exploited CVE-2023-36884 security bypass flaw.

While Microsoft initially investigated the flaw as a remote code execution flaw, it was later determined to be a security feature bypass.

This flaw allowed threat actors to create specially crafted Microsoft Office documents that could bypass the Mark of the Web (MoTW) security feature, causing files to be opened without displaying a security warning.

The vulnerability was actively exploited by the RomCom hacking group, who was previously known to deploy the Industrial Spy ransomware in attacks. The ransomware operation has since rebranded as ‘Underground,’ under which they continue to extort victims.

The flaw was discovered by Paul Rascagneres and Tom Lancaster with Volexity.

CVE-2023-38180 – .NET and Visual Studio Denial of Service Vulnerability

Microsoft has fixed an actively exploited vulnerability that can cause a DDoS attack on .NET applications and Visual Studio.

Unfortunately, Microsoft did not share any additional details on how this flaw was used in attacks and did not disclose who discovered the vulnerability.