Description
WordPress Plugin is_human() is prone to a remote command injection vulnerability because it fails to properly sanitize user-supplied input. Attackers can exploit this issue to execute arbitrary commands in the context of the application. WordPress Plugin is_human() versions 1.4.2 and prior are vulnerable.
Remediation
Disable the plugin
References
http://www.securityfocus.com/bid/47883/exploit
http://www.exploit-db.com/exploits/17299/
http://secunia.com/advisories/44627
http://packetstormsecurity.com/files/view/101497/ishuman-exec.txt