Attacking LM/NTLMv1 Challenge/Response Authentication
In Part 1 of the “LM/NTLMv1 Challenge/Response Authentication” series I discussed how both the LANMAN/NTLMv1 protocols operate and the weaknesses that plague these protocols. In this post I will demonstrate how attackers leverage these weaknesses to exploit the LANMAN/NTLMv1 protocols in order to compromise user credentials. For the remainder of this article I will be focusing on attacking the SMB protocol (Windows file sharing) as this is where LANMAN/NTLMv1 is most commonly used. Capturing the Response In order to capture a client’s LANMAN/NTLMv1 response, attackers will often utilise one of two methods: Force the client host to connect to them Conduct a man-in-the-middle (MITM) attack and “sniff” the client’s response To demonstrate these methods, I will be using the Metasploit Framework or Cain and Abel respectively. Metasploit In order for a client host to connect to us, we first need to create a listening SMB service that will accept incoming connections. Fo...