CVE-2007-2243: OpenSSH 4.6 and earlier, when ChallengeResponseAuthentication is enabled, allows remote attackers to determ...

Security readout for executives and security teams

This is an old OpenSSH account-enumeration issue. If challenge-response authentication with S/KEY is enabled, a remote party may distinguish valid user accounts from invalid ones. It does not by itself provide login access, but it can improve targeting for password guessing or social engineering. Exposure is most plausible on internet- or partner-facing SSH services running OpenSSH 4.6 or earlier with ChallengeResponseAuthentication and S/KEY enabled. Environments using newer OpenSSH, disabling challenge-response, or not exposing SSH have lower apparent exposure. Treat as a cleanup and hardening item unless legacy SSH is exposed externally. Prioritize any internet-facing systems running OpenSSH 4.6 or earlier because account discovery can support later attacks. Mitigation focus: Inventory exposed SSH services and identify OpenSSH versions at or below 4.6.; Check vendor guidance for fixed versions or supported upgrade paths.; Disable S/KEY or challenge-response authentication if not required and approved..

Prepared

Jun 29, 2026, 06:10 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.