Bug ID 476338: RSTs due to Brute Force attack while policy in transparent mode

Last Modified: Mar 12, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP ASM(all modules)

Known Affected Versions:
11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.5.4 HF2, 11.5.4 HF3, 11.5.4 HF4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.6.1, 11.6.1 HF1, 11.6.1 HF2, 11.6.2, 11.6.2 HF1, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4

Fixed In:
12.0.0

Opened: Aug 21, 2014
Severity: 2-Critical
Related AskF5 Article:
K48493650

Symptoms

When attack is detected, traffic starts to get rejected with the following RST cause: ASM requested abort (plugin abort error).

Impact

Policy is blocking (sending RSTs) even though it is in transparent mode.

Conditions

This occurs if your security policy is configured with aggressive thresholds for brute force prevention, and the security policy's enforcement mode is Transparent.

Workaround

Set the brute force configuration to alarm and not blocking.

Fix Information

Brute force configuration now accommodates the policy settings within transparent mode.

Behavior Change