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OSSEC / HIDS Rule 171303
- Rule family: OSSEC / HIDS
- Rule ID: 171303
- Definition status: Present in current source
- Alert message / subject: Known brute force attacker.
- Rule level: 12
- Definition checked: 2026-10-21
Interpretation and response
This event is recorded as “Known brute force attacker.” Review the originating log and the affected host or service to determine whether the activity was expected.
An OSSEC/HIDS event records or correlates activity. Blocking depends on the originating application and any separately configured Active Response policy; an alert alone does not prove that an attack was blocked.
Documentation
The following guidance was migrated from the historical wiki and reviewed against the rule definition. Legacy ASL product names and interface instructions refer to the versions documented then. Use the current metadata above and your installed configuration when interpreting thresholds, notification settings and response behavior.
Description
ASL has detected a known brute force attacker that is attempting to brute force accounts in your mail server.
Troubleshooting
Solutions
If you wish to prevent ASL from shunning on these events, simply set Active Response for the rule to off. This will of course allow this attacker to continue to brute force accounts in your mail server.
False Positives
None. Please do not report this as a false positive unless ASL is incorrectly reporting an event that is:
1) not exim
or
2) you know this is not a brute force attacker, and please provide your mail logs if you believe this is the case and any other information you have have to help us understand what is happening with your system.
Additional Information
External Articles
None.
Source and revision
Migrated from HIDS_171303, wiki page 548, revision 5106 (20140924). Documentation review: 2026-10-21. An archived wiki status of Active is not a current deployment status.
For assistance, provide the rule ID, installed product and rule version, and a sanitized event to Atomicorp support .