1. OVERVIEW bbPress 1.0.2 and lower versions were vulnerable to Cross Site Scripting. 2. APPLICATION DESCRIPTION bbPress is plain and simple forum software, plain and simple with a twist from the creators of WordPress. It is focused on web standards, ease of use, ease of integration, and speed. 3. VULNERABILITY DESCRIPTION The "re" parameter was not properly sanitized upon submission to the /bb-login.php url, which allows attacker to conduct Cross Site Scripting attack. This may allow an attacker to create a specially crafted URL that would execute arbitrary script code in a victim's browser. If a user has already logged in to the application, an XSS attack will execute promptly. If not, it will execute after the user's successful logging in. 4. VERSIONS AFFECTED bbPress 1.0.2 and lower 5. PROOF-OF-CONCEPT/EXPLOIT http://localhost/bb-login.php?re=data%3Atext%2Fhtml%3Bbase64%2CPHNjcmlwdD5hbGVydCgiWFNTXG4iK2RvY3VtZW50LmNvb2tpZSk8L3NjcmlwdD4%3D 6. SOLUTION Upgrade to 1.0.3 or higher 7. VENDOR bbPress Development Team http://bbpress.org/ 8. CREDIT This vulnerability was discovered by Aung Khant, http://yehg.net, YGN Ethical Hacker Group, Myanmar. 9. DISCLOSURE TIME-LINE 2010-12-23: notified vendor 2011-02-24: vendor released fixed version 2011-03-13: vulnerability disclosed 10. REFERENCES Original Advisory URL: http://yehg.net/lab/pr0js/advisories/[bbpress-1.0.2]_cross_site_scripting About bbPress: http://bbpress.org/about/ #yehg [2011-03-13]