Bug ID 693780: Proactive Bot Defense sends CAPTCHA to the UC browser on iOS devices

Last Modified: Jul 12, 2023

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

Known Affected Versions:
13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0,,,

Fixed In:

Opened: Nov 09, 2017

Severity: 3-Major


When a request arrives from UCBrowser running on iOS and without TSPD_101 (proactive bot defense cookie). The big-ip respond with captcha challenge.


UC browser end-user presented with captcha challenge.


Dos profile attached to a virtual. Dos profile has application security enabled. Dos profile has proactive bot defense enabled.


Increase proactive bot defense score. list sys db dosl7.browser_legit_min_score_captcha sys db dosl7.browser_legit_min_score_captcha { value "60" }

Fix Information

User agent parser has been changed (adjusted) for the UC browser. The UC browser is detected as safari ios.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips