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OSSEC / HIDS Rule 3357

OSSEC / HIDS rule catalog

  • Rule family: OSSEC / HIDS
  • Rule ID: 3357
  • Definition status: Present in current source
  • Alert message / subject: Multiple rapid SASL authentication failures.
  • Rule level: 10
  • Definition checked: 2026-10-21
  • Configured frequency: 3
  • Timeframe (seconds): 2

Correlation values are configuration attributes; event-count behavior depends on the manager version and parent rules.

Interpretation and response

This event is recorded as “Multiple rapid SASL authentication failures.” 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

This rule reports when your systems mail server has rejected multiple attempts to authenticate. By default this is 6 failures within a 120 second period. Typically this occurs with brute force authentication attempts.

ASL does not control or configure this behavior, it merely reports when this occurs. Therefore, if your mail server or other daemon is incorrectly rejecting authentication from one of your users you will need to configure your mail server, or other daemon, correctly. Please contact the vendor for this service for assistance with configuring it.

Disabling this rule will not allow your users to authenticate to the service. It will simply “silence” the alert in ASL, however the users authentication will still be rejected by the service.

Troubleshooting

False Positives

This rule is not caused by ASL (historical reference). ASL merely reports the alert from the service on your system that has rejected these authentication requests.

A False Positive may occur if many users are located behind the same IP address, and they are all failing to authenticate properly within 120 seconds. We recommend you correct the authentication credentials before you disable this rule. Its is highly unusual for multiple users to experience authenticate failures at the same time.

Tuning Guidance

If you wish to not block these connections, just disable Active Response in the ASL (historical reference) rule manager.

Additional Information

Notes

Example log messages:

Illustrative event summary (not a captured log): OSSEC/HIDS 3357 — Multiple rapid SASL authentication failures..

Source and revision

Migrated from HIDS_3357, wiki page 407, revision 2741 (20120925). 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 .