Bug ID 643155: ASM JavaScript features fail when LTM Policy has a default rule which disables ASM

Last Modified: Oct 24, 2019

Bug Tracker

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

Known Affected Versions:
12.0.0, 12.0.0 HF1, 12.0.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 12.1.2 HF1, 12.1.2 HF2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 12.1.5, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 14.0.0, 14.0.0.1, 14.0.0.2, 14.0.0.3, 14.0.0.4, 14.0.0.5, 14.0.1, 14.0.1.1

Opened: Feb 03, 2017
Severity: 4-Minor

Symptoms

The JavaScript features in the ASM Policy utilize requests to /TSbd/* URLs which are handled by the BIG-IP and not sent to the back-end server. When there is an LTM Policy which has a default rule of "asm disable", these URLs will not be handled by bd, and will be sent to the back-end server, which typically responds with 404 Not Found, causing these features to fail. The impacted features are: * Web Scraping Bot Detection * AJAX Blocking Page * CSRF Protection * Single-Page Application * Client-Side mitigation of Web Scraping Session Opening * Client-Side mitigation of Brute Force

Impact

Legitimate requests may get blocked.

Conditions

LTM Policy has a default rule which disables ASM.

Workaround

If the LTM Policy has a default rule which disables ASM, then the workaround is to add a rule in the LTM Policy so that all requests to URL /TSbd/* go to the ASM Policy (any policy could be used for this case).

Fix Information

None

Behavior Change