From reading some of the comments on that thread, it appears to be a generic attack aimed at entire servers instead of a WordPress specific attack.

Notice the mention by some people of the code being in all index.php files? That indicates a process running on the server searching for index.php files and automatically appending code to them, regardless of whether it's WP or not.

One guy found a copy of wunderbar emporium on his site as well. Wunderbar emporium is one possible name for a root privilege escalation trick on older Linux kernels (it was also called sock_sendpage null pointer dereferencing, but that name isn't very interesting).