An unauthenticated attacker may exploit a scenario where a Hashed Message Authentication Code (HMAC) credential, extracted from a system missing specific security patches, is reused in a replay attack against a different system. Even if the target system is fully patched, successful exploitation could result in complete system compromise, affecting confidentiality, integrity, and availability.
The use of single-factor authentication can lead to unnecessary risk of compromise when compared with the benefits of a dual-factor authentication scheme.