Hacked WordPress sites – code in header.php

Hi,

Today I noticed that all my wordpress sites were loading extremely slow. I searched deeper and I found the following code in all themes’ (either active or inactive) header.php file:

[Code moderated. Please do not post hack code blocks in the forums. Please use the pastebin if absolutely necessary/]

Does anyone have an idea what this code does?

When I removed the code from all of the sites they started to load fast as before. I checked for some other files modified on the same date as header.php but I couldn’t find any.