A worm is going around the net attacking sites running phpBB <2.0.11 with php <4.3.10.
Version 2.0.11 is the only safe version, upgrade to it now if you are not running it and upgrade php to fix the hole.
Information
http://www.securiteam.com/unixfocus/6J00O15BPS.html
http://www.f-secure.com/weblog/
http://www.phpbb.com/phpBB/viewtopic.ph ... ernosanity