SMB (Server Message Block) relay attack

is a type of attack that allows an attacker to take over a victim's computer or gain unauthorized access to a network resource by exploiting the way that Windows computers authenticate with each other using SMB.

Here's how an SMB relay attack works:

1. The attacker sets up a fake SMB server on their machine.
2. The attacker intercepts an SMB authentication request from the victim's computer. This can be done using a tool like Responder or by sniffing network traffic.
3. The attacker relays the authentication request to the target server, pretending to be the victim's computer.
4. The target server sends an SMB challenge to the attacker, who relays it back to the victim's computer.
5. The victim's computer responds to the challenge with its NTLMv2 hash.
6. The attacker uses a tool like Hashcat to crack the NTLMv2 hash and obtain the victim's plaintext password.
7. The attacker can now use the victim's credentials to gain unauthorized access to other systems and resources on the network.