Summary

It is possible to obtain a user's NTLM hash by tricking them into cloning from a malicious server. Since NTLM hashing is weak, it is possible for the attacker to brute-force the user's account name and password.

Proof of Concept

An attacker who can control a server from which the attack's target clones a repository can extract the NTLM hash, which in turn allows brute-forcing the password. Steps to reproduce:

1- Run responder on host [attacker]
2- Run git clone [victim]
3- attacker receives user's NTLM hash

Impact

By brute-forcing the NTLMv2 hash (which is expensive, but possible), credentials can be extracted.

References

• https://support.microsoft.com/en-us/topic/upcoming-changes-to-ntlmv1-in-windows-11-version-24h2-and-windows-server-2025-c0554217-cdbc-420f-b47c-e02b2db49b2e
• https://techcommunity.microsoft.com/blog/windows-itpro-blog/the-evolution-of-windows-authentication/3926848
• https://learn.microsoft.com/en-au/windows/whats-new/deprecated-features#:~:text=NTLM