Description
Joomla! Core is prone to a vulnerability that lets attackers upload arbitrary files because the application fails to properly verify user-supplied input. An attacker can exploit this vulnerability to upload arbitrary code and run it in the context of the webserver process. This may facilitate unauthorized access or privilege escalation; other attacks are also possible. Joomla! Core version 1.5.12 is vulnerable.
Remediation
Update to Joomla! Core version 1.5.13 or latest
References
http://www.securityfocus.com/bid/35780/exploit
https://www.exploit-db.com/exploits/10183/
https://developer.joomla.org/security-centre/301-20090722-core-file-upload.html