The F5 BIG-IP appliance IPsec VPN must be configured to use FIPS-validated SHA-2 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, DoW systems must 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.

From the BIG-IP GUI: 1. Network. 2. IPsec. 3. IKE Peers. 4. Click on the name of the IKE peer. 5. Verify "SHA-1" or "MD5" is not selected for the following: IKE Phase 1 Algorithms >> Authentication Algorithm IKE Phase 1 Algorithms >> Pseudo-Random Function

From the BIG-IP GUI: 1. Network. 2. IPsec. 3. IPsec Policies. 4. Click the name of the IPsec Policy. 5. Verify "SHA-1" is not selected for the following: IKE Phase 2 >> Authentication Algorithm

If the BIG-IP appliance is not configured to use FIPS-validated SHA-2 or higher for IKE, this is a finding.

From the BIG-IP GUI: 1. Network. 2. IPsec. 3. IKE Peers. 4. Click on the name of the IKE peer. 5. Configure SHA-2 or higher for the following: IKE Phase 1 Algorithms >> Authentication Algorithm IKE Phase 1 Algorithms >> Pseudo-Random Function 6. Click "Update".

From the BIG-IP GUI: 1. Network. 2. IPsec. 3. IPsec Policies. 4. Click the name of the IPsec Policy. 5. Configure SHA-2 or higher for the following: IKE Phase 2 >> Authentication Algorithm 6. Click "Update".