Description
The CAPTCHA functionality in php-Nuke 6.0 through 7.9 uses fixed challenge/response pairs that only vary once per day based on the User Agent (HTTP_USER_AGENT), which allows remote attackers to bypass CAPTCHA controls by fixing the User Agent, performing a valid challenge/response, then replaying that pair in the random_num and gfx_check parameters.
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- PHP-Nuke 7.x - CAPTCHA Bypass EDB-27249 · webapps · Feb 18, 2006 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
References
- 16722 vdb-entry
- 455 third-party-advisory
- 20060218 [waraxe-2006-SA#045] - Bypassing CAPTCHA in phpNuke 6.x-7.9 mailing-list
- 18936 third-party-advisory
- http://www.waraxe.us/advisory-45.html