The IPSec VPN must be configured to use FIPS-validated SHA-2 at 384 bits or higher for Internet Key Exchange (IKE).

Without cryptographic integrity protections, information can be altered by unauthorized users without detection.

Although allowed by SP800-131Ar2 for some applications, SHA-1 is considered a compromised hashing standard and is being phased out of use by industry and government standards. Unless required for legacy use, DOD systems should not be configured to use SHA-2 for integrity of remote access sessions.

This requirement is applicable to the configuration of IKE Phase 1 and Phase 2.

Verify the IPsec VPN Gateway uses IKE with SHA-2 at 384 bits or greater to protect the authenticity of communications sessions.

If the IPsec VPN Gateway is not configured to use IKE with SHA-2 at 384 bits or greater to protect the authenticity of communications sessions, this is a finding.

Configure the IPsec VPN Gateway to use IKE with SHA-2 at 384 bits or greater to protect the authenticity of communications sessions.