If you’re a PHP developer you will immediately recognize this as looking strange: It is a PHP directive to include an external file containing PHP source code, but the file is actually an image. The infection is relatively simple: Inside a nulled script there’s a little line of code that looks like this: Fox-IT have dubbed it CryptoPHP because of the fact that it encrypts data before it sends it to command and control servers. It’s come to our attention courtesy of Fox-IT that nulled scripts are being distributed via several websites with a sophisticated infection pre-installed. They include commercial WordPress themes and plugins. They are the web equivalent of pirated software.
Nulled scripts are commercial web applications that you can obtain from pirate websites that have been modified to work without a license key.
I’ve summarized the details and our response: Our friends over at Fox-IT based in Delft in the Netherlands just contacted me with some amazing research they’ve just published. If you’re technically minded and want as much detail as possible, I recommend you skip this blog entry and head straight over to the Whitepaper that Fox-IT has published on the CryptoPHP backdoor (It’s 50 pages). WordPress Security: Nulled Scripts and the CryptoPHP Infection
