HIDS 31102
| Rule 31102 | |
|---|---|
| Status | Active |
| Alert Message | ModSecurity: Access denied with code 400. Too many threads |
Contents |
Description
This rule is triggered when a a single IP has opened too many connections to the server (11 or more), and they are in a READ state. This condition is extremely unusual for a normal client, and occurs when an attacker is trying to use up all the threads on the server to prevent it from servicing any other clients. This occurs when a slowloris attack is occuring.
This rule does not block anything, it simply reports when apache has stopped accepting READ requests from a client. You can configure this limit by following the Tuning Guidance below.
Troubleshooting
False Positives
= The rule alerts when the configured WAF_READSTATELIMIT value is exceeded. The rule does not cause this event to occur. Disabling this rule will not cause this event to not occur, it will just prevent ASL from alerting you that this is occurring. See below for tuning guidance.
Tuning Guidance
This limit is configured by this setting:
https://www.atomicorp.com/wiki/index.php/ASL_WAF#WAF_READSTATELIMIT
Additional Information
Similar Rules
None.
Knowledge Base Articles
None.
Outside References
None.
