refactor(sshd-logs): split ssh_failed-auth into distinct log_types #1650
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The ssh-time-based-bf scenario was incorrectly triggering because a single SSH login attempt generates multiple log lines (Invalid user, pam_unix auth failure, Failed password, Connection closed), all previously tagged as ssh_failed-auth. This caused 1 real attempt to be counted as 3-4 events, inflating the count and skewing the MedianInterval calculation. Split ssh_failed-auth into distinct log_types per event category: - ssh_password_fail: actual auth failures (Failed password for) - ssh_invalid_user: username probing (Invalid user from) - ssh_pam_failure: PAM notification (duplicate signal, unused) - ssh_preauth_close: connection lifecycle (Connection closed [preauth]) - ssh_not_allowed: AllowUsers blocks - ssh_bad_banner, ssh_bad_keyexchange, ssh_magic_failed: protocol anomalies Added new scenarios for complete coverage (one per bucket): - ssh-invalid-user: detect username probing - ssh-preauth-scan: detect preauth disconnect scanning - ssh-not-allowed: detect blocked user attempts - ssh-scanner: detect protocol anomalies Updated existing scenarios (ssh-bf, ssh-slow-bf, ssh-time-based-bf) to use ssh_password_fail for accurate 1:1 counting of actual auth attempts. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Description
The ssh-time-based-bf scenario was incorrectly triggering because a single SSH login attempt generates multiple log lines (Invalid user, pam_unix auth failure, Failed password, Connection closed), all previously tagged as ssh_failed-auth. This caused 1 real attempt to be counted as 3-4 events, inflating the count and skewing the MedianInterval calculation.
Split ssh_failed-auth into distinct log_types per event category:
Added new scenarios for complete coverage (one per bucket):
Updated existing scenarios (ssh-bf, ssh-slow-bf, ssh-time-based-bf) to use ssh_password_fail for accurate 1:1 counting of actual auth attempts.
Checklist