The Internet Key Exchange v1 main mode is vulnerable to offline dictionary or brute force attacks. Reusing a key pair across different versions and modes of IKE could lead to cross-protocol authentication bypasses. It is well known, that the aggressive mode of IKEv1 PSK is vulnerable to offline dictionary or brute force attacks. For the main mode, however, only an online attack against PSK authentication was thought to be feasible. This vulnerability could allow an attacker to recover a weak Pre-Shared Key or enable the impersonation of a victim host or network.

Multiple unspecified vulnerabilities in multiple unspecified implementations of Internet Key Exchange version 1 (IKEv1) have multiple unspecified attack vectors and impacts related to denial of service, as demonstrated by the PROTOS ISAKMP Test Suite for IKEv1. NOTE: due to the lack of information in the original sources, it is likely that this candidate will be REJECTed once it is known which implementations are actually vulnerable. In addition, since "denial of service" is an impact and not a vulnerability, it is unknown which underlying vulnerabilities are actually covered by this particular candidate.