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A recently discovered vulnerability in Microsoft's Active Directory group policy allows for NTLMv1 authentication despite its official deprecation. Experts warn that misconfigured applications can bypass the Group Policy mechanism, making it essential to stay vigilant about potential security threats.
A new vulnerability in Microsoft Active Directory group policy enables NTLMv1 authentication despite its official deprecation. Misconfigured applications can bypass the Group Policy mechanism, allowing NTLMv1 attacks to occur. The vulnerability arises from the use of Netlogon Remote Protocol (MS-NRPC) data structure. Experts recommend enabling audit logs for all NTLM authentication and keeping systems up-to-date with latest security patches. The discovery highlights the need for ongoing vigilance in cybersecurity to identify and address potential security risks.
The discovery of a new vulnerability in the Microsoft Active Directory group policy has sent shockwaves throughout the cybersecurity community. According to recent research, a simple misconfiguration in on-premise applications can override the group policy designed to disable NT LAN Manager (NTLM) v1, effectively negating the security measures put in place.
In an effort to combat the growing threat of NTLMv1 attacks, Microsoft had implemented a group policy that disabled the legacy authentication protocol. However, researchers at Silverfort have found that this measure can be easily circumvented by misconfigured applications.
The vulnerability arises from the use of the Netlogon Remote Protocol (MS-NRPC), which contains a data structure called NETLOGON_LOGON_IDENTITY_INFO. This data structure has a field named ParameterControl that, in turn, has a configuration to "Allow NTLMv1 authentication (MS-NLMP) when only NTLMv2 (NTLM) is allowed."
Silverfort researcher Dor Segal explained that "the Group Policy mechanism is Microsoft's solution to disable NTLMv1 across the network. The LMCompatibilityLevel registry key prevents Domain Controllers from evaluating NTLMv1 messages and returns a wrong password error (0xC000006A) when authenticating with NTLMv1."
However, by leveraging this configuration in the MS-NRPC data structure, applications can be configured to enable NTLMv1 authentication, effectively bypassing the group policy.
Segal further explained that "meaning, organizations think they are doing the right thing by setting this group policy, but it's still being bypassed by the misconfigured application." This highlights the importance of regular vulnerability assessments and penetration testing in identifying potential security weaknesses.
To mitigate the risk posed by NTLMv1, experts recommend enabling audit logs for all NTLM authentication in the domain and keeping an eye out for vulnerable applications that request clients to use NTLMv1 messages. Additionally, organizations are advised to keep their systems up-to-date with the latest security patches.
Furthermore, the discovery of this vulnerability serves as a reminder of the need for ongoing vigilance in cybersecurity. As threat actors continue to evolve and find new ways to exploit vulnerabilities, it is crucial that organizations remain proactive in identifying and addressing potential security risks.
The findings of this research have significant implications for organizations that rely on Microsoft Active Directory for authentication and authorization purposes. The discovery of this vulnerability highlights the importance of implementing robust security measures to protect against NTLMv1 attacks.
In conclusion, the new vulnerability found in the Active Directory group policy underscores the need for continued vigilance in cybersecurity. By staying informed about emerging threats and taking proactive steps to address potential security weaknesses, organizations can minimize their risk exposure and ensure a more secure computing environment.
A recently discovered vulnerability in Microsoft's Active Directory group policy allows for NTLMv1 authentication despite its official deprecation. Experts warn that misconfigured applications can bypass the Group Policy mechanism, making it essential to stay vigilant about potential security threats.
Related Information:
https://thehackernews.com/2025/01/researchers-find-exploit-allowing.html
https://www.silverfort.com/blog/ntlmv1-bypass-in-active-directory-technical-deep-dive/
Published: Thu Jan 16 09:53:51 2025 by llama3.2 3B Q4_K_M