This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

WAF exception rules for false positives

I'm trying to protect an IIS based web server called Precision BI. 

When SQL injection protection is enabled, a user cannot change their password. When using the XSS protection, and running a search function, we see a 403 error.When using cookie signing, the login page doesn't populate the server and database names field.


I see an option for exceptions for web clients coming from source networks, which is difficult if no impossible for me to use that option. The "Web requests matching this path" exception is interesting, but unsure how to apply it.

I also see Skip WAF rules option, but don't see the rule number in the log. How do you determine the rule that is causing a false positive?


Does anyone have a suggestion on how I can tune the WAF to protect a web server who's standard functionality appears to be blocked with false positives?

In the log I'm seeing:
] Dropping cookie '.ASPXAUTH' from request due to missing/invalid signature, referer: 

ModSecurity: Rule execution error - PCRE limits exceeded (-8): (null).

method="POST" statuscode="403" reason="waf" extra="Anomaly Score Exceeded (score 200): XSS Attack Detected" time="121208"  


Thanks!
Brian


This thread was automatically locked due to age.
Parents
  • From the help
    "Skip WAF Rules: Add WAF rule numbers to this box which you want to skip for the current profile, for example because they return false positives. WAF rule numbers can be retrieved on the Logging & Reporting > Web Application Firewall > Details page, via the Top Rules filter."



    I don't see any stats on this details page, no top rules, top attackers or anything listed here. Shows all 0's
  • What version of ASG are you using?  The WAF reporting was pretty broken in the 8.3xx releases... I think this is fixed in V9 though.

    CTO, Convergent Information Security Solutions, LLC

    https://www.convergesecurity.com

    Sophos Platinum Partner

    --------------------------------------

    Advice given as posted on this forum does not construe a support relationship or other relationship with Convergent Information Security Solutions, LLC or its subsidiaries.  Use the advice given at your own risk.

Reply
  • What version of ASG are you using?  The WAF reporting was pretty broken in the 8.3xx releases... I think this is fixed in V9 though.

    CTO, Convergent Information Security Solutions, LLC

    https://www.convergesecurity.com

    Sophos Platinum Partner

    --------------------------------------

    Advice given as posted on this forum does not construe a support relationship or other relationship with Convergent Information Security Solutions, LLC or its subsidiaries.  Use the advice given at your own risk.

Children
No Data