Kali Linux

Nosferatu : Lsass NTLM Authentication Backdoor

Nosferatu is a Lsass NTLM Authentication Backdoor

How It Works

First, the DLL is injected into the lsass.exe process, and will begin hooking authentication WinAPI calls. The targeted function is MsvpPasswordValidate(), located in NtlmShared.dll. In the pursuit of not being detected, the hooked function will call the original function and allow for the normal flow of authentication. Only after seeing that authentication has failed will the hook swap out the actual NTLM hash with the backdoor hash for comparison.

Usage

Nosferatu must be compiled as a 64 bit DLL. It must be injected using the a DLL Injector with SeDebugPrivilege.

You can see it loaded using Procexp:

Login example using Impacket:

R K

Recent Posts

git fetch vs git pull: How They Work and When to Use Each

Both git fetch and git pull talk to a remote repository, but they do very different things to your…

1 week ago

git cherry-pick Command: Apply Commits from Another Branch

Sometimes the change you need already exists, just on the wrong branch. A hotfix lands…

1 week ago

Best Email APIs for Secure Business Email: Why Developers Are Moving Beyond SMTP

Email is still one of the most important communication channels inside modern applications. Password resets,…

1 week ago

Nginx Commands in Linux: Start, Stop, Reload, Test, and Log

Nginx is a high-performance web server and reverse proxy trusted by some of the largest…

2 weeks ago

ufw Command in Linux: Manage Firewall Rules with Examples

ufw (Uncomplicated Firewall) sits on top of iptables (or nftables on newer systems) and replaces…

2 weeks ago

who Command in Linux: Show All Logged-In Users and Sessions

When you share a server with a team or investigate unexpected activity, the first question…

2 weeks ago