Google Chrome 43.0.2357.124 XSS Filter Bypass

CVE	Category	Price	Severity
CVE-2015-1265	CWE-79	N/A	High

Author	Risk	Exploitation Type	Date
Unknown	High	Remote	2015-06-25

Our sensors found this exploit at: http://cxsecurity.com/ascii/WLB-2015060154

Below is a copy:

Google Chrome 43.0.2357.124 XSS Filter BypassHi! Just wanted to share my finding. Ive found a way to bypass Chromes anti-xss filter. This bypass is universal, and it defeats Chromes XSSAuditor in all cases!

If you find it interesting for you, or for your readers, here are the details:

Description
XSS attacks occur when one website injects JavaScript code into otherwise legitimate requests to another website. The injected script generally attempts to access privileged information. The XSS Filter detects JavaScript in URL and HTTP POST requests. If JavaScript is detected, the XSS Filter searches evidence of reflection. If reflection is detected, the XSS Filter sanitizes the original request so that the additional JavaScript cannot be executed. However, the XSS filter can by bypassed with leading regexp inside svg script tag.

Details
Title: Google Chrome Anti-XSS Filter Bypass
Affected Products: Google Chrome 43.0.2357.124 m (letest stable version)
Discovery Date: 16-06-15
Author: Yosi Ovadia (http://vulnerable.info/)
Payload: <svg><script>/<1/>alert(document.domain)</script></svg>

POC
http://vulnerable.info/poc/poc.php?foo=%3Csvg%3E%3Cscript%3E/%3C1/%3Ealert(document.domain)%3C/script%3E%3C/svg%3E

Reporting
The issue was reported to chromium security team, and was fixed within 5 hours. The team marked it as a significant bypass.

Patch
https://codereview.chromium.org/1187843005/

Revision
http://src.chromium.org/viewvc/blink?view=revision&revision=197282

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