A critical zero-day vulnerability in Windows’ Mark of the Web (MotW) security feature has been discovered, affecting Windows Server 2012 and Server 2012 R2 systems. The security flaw, which has existed for over two years, now has an unofficial solution through the 0patch platform.

The vulnerability compromises the MotW feature, which typically alerts users about files downloaded from untrusted sources. This security bypass could potentially expose systems to malicious files without triggering standard security warnings.

ACROS Security’s 0patch has stepped in with free micropatches to protect affected systems while Microsoft’s official fix remains pending. The solution targets Windows Server 2012 and Server 2012 R2 systems running October 2023 updates, including those with Extended Security Updates.

Users can implement the security fix by:
– Creating a 0patch account
– Installing the 0patch agent
– Enabling automatic micropatch deployment

0patch co-founder Mitja Kolsek notes that such vulnerabilities are common, particularly affecting systems with outdated security measures. The company is maintaining discretion about vulnerability details until Microsoft releases an official patch.

Microsoft has yet to comment on this security concern or provide a timeline for an official fix.