Reports of a mass file injection attack were seen over the weekend. Upwards of 400,000 sites seem to have been affected so far by URLs that download a file that seems to be related to the Zlob trojan. Most of these sites seem to be running phpBB forum software. If you have the capability you may want to examine egress logs and/or blacklist the two URLs that are currently known to be distributors. Those URLs are:

hxxp://free.hostpinoy.info/f.js
hxxp://xprmn4u.info/f.js