Researchers Find Exploit Allowing NTLMv1 Despite Active Directory Restrictions
Jan 16, 2025
Active Directory / Vulnerability
Cybersecurity researchers have found that the Microsoft Active Directory Group Policy that's designed to disable NT LAN Manager (NTLM) v1 can be trivially bypassed by a misconfiguration. "A simple misconfiguration in on-premise applications can override the Group Policy, effectively negating the Group Policy designed to stop NTLMv1 authentications," Silverfort researcher Dor Segal said in a report shared with The Hacker News. NTLM is a still widely used mechanism particularly in Windows environments to authenticate users across a network. The legacy protocol, while not removed due to backward compatibility requirements, has been deprecated as of mid 2024. Late last year, Microsoft officially removed NTLMv1 starting in Windows 11, version 24H2, and Windows Server 2025. While NTLMv2 introduces new mitigations to make it harder to perform relay attacks, the technology has been besieged by several security weaknesses that have been actively exploited by threat acto...
