Domains: http://lxr.mozilla.org/ http://mxr.mozilla.org/ (The two domains above are almost the same) Websites information: lxr.mozilla.org, mxr.mozilla.org are cross references designed to display the Mozilla source code. The sources displayed are those that are currently checked in to the mainline of the mozilla.org CVS server, Mercurial Server, and Subversion Server; these pages are updated many times a day, so they should be pretty close to the latest‑and‑greatest. (from Mozilla) Vulnerability description: All pages under the following two URLs are vulnerable. http://lxr.mozilla.org/mozilla-central/source http://mxr.mozilla.org/mozilla-central/source This means all URLs under the above two domains can be used for XSS attacks targeting Mozilla's users. Since there are large number of pages under them. Meanwhile, the contents of the two domains vary. This makes the vulnerability very dangerous. Attackers can use different URLs to design XSS attacks to Mozilla's variety class of users. The vulnerability have been reported to bugzilla.mozilla.org. Mozilla are dealing with this issue. POCs: http://lxr.mozilla.org/mozilla-central/source/ http://lxr.mozilla.org/mozilla-central/source/mobile/android/ http://lxr.mozilla.org/mozilla-central/source/Android.mk/ http://lxr.mozilla.org/mozilla-central/source/storage/public/mozIStorageBindingParamsArray.idl/ http://lxr.mozilla.org/mozilla-central/source/netwerk/protocol/device/AndroidCaptureProvider.cpp http://mxr.mozilla.org/mozilla-central/source/ http://mxr.mozilla.org/mozilla-central/source/webapprt/ http://mxr.mozilla.org/mozilla-central/source/mozilla-config.h.in/ http://mxr.mozilla.org/mozilla-central/source/chrome/nsChromeProtocolHandler.h/ http://mxr.mozilla.org/mozilla-central/source/security/sandbox/linux/x86_32_linux_syscalls.h/ POC Video: https://www.youtube.com/user/tetraph Vulnerability Analysis: Take the following link as an example, http://lxr.mozilla.org/mozilla-central/source/chrome/ We can see that for the page reflected, it contains the following codes. If we insert "" into the URL, the code can be executed. The vulnerability can be attacked without user login. My tests were performed on Firefox (26.0) in Ubuntu (12.04) and IE (9.0.15) in Windows 7. Cross-site scripting (XSS) is a type of computer security vulnerability typically found in Web applications. XSS enables attackers to inject client-side script into Web pages viewed by other users. A cross-site scripting vulnerability may be used by attackers to bypass access controls such as the same origin policy. (From Wikipedia) Posted By: Wang Jing, mathematics student from Nanyang Technological University, Singapore. http://tetraph.com/wangjing/ More Details: http://www.tetraph.com/blog/xss-vulnerability/mozilla-mozilla-org-two-sub-domains-cross-reference-xss-vulnerability-all-urls-under-the-two-domains/ http://lxr.mozilla.org/mozilla-central/source http://mxr.mozilla.org/mozilla-central/source