Bug ID 570905: Some Internet Explorer Browsers challenged with CAPTCHA when "Proactive Bot Defense" is enabled

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP ASM(all modules)

Known Affected Versions:
12.0.0, 12.0.0 HF1, 12.1.0 HF1, 12.0.0 HF2, 12.1.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2

Opened: Jan 30, 2016

Severity: 3-Major

Symptoms

Some rare cases of Internet Explorer browsers that are running on Windows Server and connected via Remote Desktop may receive a CAPTCHA challenge instead of passing through directly, when "Proactive Bot Defense" is enabled on the DoS profile, and "Block requests from suspicious browsers" is also enabled.

Impact

Some rare cases of Internet Explorer browsers that are running on Windows Server and connected via Remote Desktop may receive a CAPTCHA challenge instead of passing through directly.

Conditions

"Proactive Bot Defense" is enabled on the DoS profile, and "Block requests from suspicious browsers" is also enabled.

Workaround

Disabling the "Block requests from suspicious browsers" check-box on the DoS profile will prevent this problem.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips