Which SMB feature is used to prevent man-in-the-middle attacks?

Which SMB feature is used to prevent man-in-the-middle attacks?

• A. SMB Multichannel
• B. Pre-Authentication integrity
• C. SMB Encryption
• D. Cluster Dialect Fencing

Answer: (B)

The key idea is protecting the SMB authentication handshake from tampering by a man-in-the-middle. Pre-Authentication Integrity adds a cryptographic check on the data used before credentials are exchanged, so if someone in the middle tries to modify the negotiation or impersonate the server, the mismatch is detected and the connection is blocked before authentication completes. This directly stops MITM attempts during the login phase. SMB Encryption focuses on keeping the actual data protected once a session is established, not on preventing tampering during the pre-authentication handshake. SMB Multichannel enhances security and performance across multiple channels (and can apply signing/encryption), but it isn’t specifically about preventing MITM during the pre-authentication step. Cluster Dialect Fencing deals with ensuring the cluster nodes use approved dialects and isn’t about MITM protection during SMB authentication. So the feature that best prevents man-in-the-middle attacks during SMB authentication is Pre-Authentication Integrity.

The key idea is protecting the SMB authentication handshake from tampering by a man-in-the-middle. Pre-Authentication Integrity adds a cryptographic check on the data used before credentials are exchanged, so if someone in the middle tries to modify the negotiation or impersonate the server, the mismatch is detected and the connection is blocked before authentication completes. This directly stops MITM attempts during the login phase.

SMB Encryption focuses on keeping the actual data protected once a session is established, not on preventing tampering during the pre-authentication handshake. SMB Multichannel enhances security and performance across multiple channels (and can apply signing/encryption), but it isn’t specifically about preventing MITM during the pre-authentication step. Cluster Dialect Fencing deals with ensuring the cluster nodes use approved dialects and isn’t about MITM protection during SMB authentication.

So the feature that best prevents man-in-the-middle attacks during SMB authentication is Pre-Authentication Integrity.