Bug ID 693782: Mobile UC browser has been blocked by Proactive Bot Defense

Last Modified: Jul 12, 2023

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

Fixed In:

Opened: Nov 09, 2017

Severity: 3-Major


A request from UC Browser installed on a mobile device is blocked (got RST packet or captcha).


Requests from mobile UC browser are blocked.


-- ASM or DoS is provisioned. -- Proactive Bot Defense enabled within DoS profile. -- The DoS profile attached to a virtual server.


To work around this issue, you can use either of the following workarounds: -- Disable Proactive Bot Defense. -- Change browser_legit_min_score_drop sys db to be higher value. To do so, use a configuration similar to the following: list sys db dosl7.browser_legit_min_score_drop sys db dosl7.browser_legit_min_score_drop { value "120" }

Fix Information

Mobile UC browser is no longer blocked by Proactive Bot Defense checks.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips