CASA-VN-000630 - The Cisco ASA remote access VPN server must be configured to use SHA-2 or greater for hashing to protect the integrity of IPsec remote access sessions - IPsec SA
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. DoD systems must not be configured to use SHA-1 for integrity of remote access sessions. The remote access VPN provides access to DoD non-public information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network.
Configure the ASA to use SHA-2 or greater for hashing to protect the integrity of IPsec remote access sessions as shown in the example below. ASA1(config)# crypto ikev2 policy 1 ASA1(config-ikev2-policy)# integrity sha256 ASA1(config-ikev2-policy)# exit ASA1(config)# crypto ipsec ikev2 ipsec-proposal IPSEC_TRANS ASA1(config-ipsec-proposal)# protocol esp integrity sha-256 ASA1(config-ikev2-policy)# end