# Title: Chrome 31.0 Webkit XSS Auditor Bypass # Product: Google Chrome # Author: Rafay Baloch @rafaybaloch And PEPE Vila # Company: Majorsecurity GMBH # Website: Majorsecurity.com ============ Description ============ Chrome XSS Auditor is a client side XSS filter used by google chrome to protect against XSS attacks. Chrome XSS filter has already been beaten ltos of times, so we thought why don't we give a try. ============ Vulnerability ============ There is a certain criteria that needs to be met for this bypass, For this bypass the server side filter should convert an aprostrophe ' to dash -, which is a commonly known practice. ================ Proof of concept ================ The following is a challenge setup by a gentle man with a nick "Strong boi": http://12342.site11.com/level2.php The expected solution was to use a well known unfixed bug in chrome and using both parameters a and b to execute the javascript. However, we noticed a different behavior, when we injected an apostrophe. It was being converted to - and hence yielding a valid syntax and executing the javascript. http://12342.site11.com/level2.php?a=%22%3E%3Cscript%3E'alert(0);%3C/script%3E Output Source: First search:<input type="text" name="a" value="<script>1-alert(0);</script>"/><br>