AOS, when used as a VPN Gateway, must be configured to use IPsec with SHA-2 at 384 bits or greater for hashing to protect the integrity of remote access sessions.

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

SHA-1 is considered a compromised hashing standard and is being phased out of use by industry and government standards. DoW systems must not be configured to use SHA-1 for integrity of remote access sessions.

The remote access VPN provides access to DoW nonpublic information systems by an authorized user (or an information system) communicating through an external, nonorganization-controlled network.

Satisfies: SRG-NET-000063-VPN-000220, SRG-NET-000074-VPN-000250, SRG-NET-000168-VPN-000600, SRG-NET-000230-VPN-000780

1. Verify the AOS configuration with the following command: show crypto-local ipsec-map

Note the IKEv2 Policy number for each configured map.

2. For each configured policy number, run the following command: show crypto isakmp policy <IKEv2 Policy #>

If each configured IKEv2 policy hash algorithm is not configured with SHA-2 at 384 bit, this is a finding.

Configure AOS with the following commands: configure terminal crypto isakmp policy <priority> hash sha2-384-192 exit write memory