[deefour]

I've seen this sort of thing from the Darkleech apache module[1]. It also won't show the malicious Javascript to any IP that appears in the `last` log. It looks like php.net uses Apache too[2]. The easiest way I've seen to find the module (they come with a variety of names) is to do something like

  strings /path/to/modules/* | grep -i blacklist

[1] http://malwaremustdie.blogspot.com/2013/03/the-evil-came-bac...

[2] http://builtwith.com/php.net