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

How to Prevent Software Supply Chain Attacks

What is a Software Supply Chain Attack? A software supply chain attack occurs when a…

1 week ago

How UDP Works and Why It Is So Fast

When people ask how UDP works, the simplest answer is this: UDP sends data quickly…

3 weeks ago

How EDR Killers Bypass Security Tools

Endpoint Detection and Response (EDR) solutions have become a cornerstone of modern cybersecurity, designed to…

3 weeks ago

AI-Generated Malware Campaign Scales Threats Through Vibe Coding Techniques

A large-scale malware campaign leveraging AI-assisted development techniques has been uncovered, revealing how attackers are…

3 weeks ago

How Does a Firewall Work Step by Step

How Does a Firewall Work Step by Step? What Is a Firewall and How Does…

3 weeks ago

Fake VPN Download Trap Can Steal Your Work Login in Minutes

People trying to securely connect to work are being tricked into doing the exact opposite.…

3 weeks ago