Dubbed Santy.e, the worm differed significantly from its predecessors, said Russia-based Kaspersky Labs in an alert.
Rather than only target websites running phpBB -- software for creating internet forums using the PHP scripting language -- the worm could exploit any site left allowed arbitrary file inclusion into PHP scripts.
"This can only be prevented with decent, secure coding," said Kaspersky Labs. "Every site [that uses PHP] is potentially in danger."
Kaspersky noted it had already received reports of websites attacked by infected systems and that some servers have been compromised or dramatically slowed down as their loads climbed under constant probing.
Like earlier Santy variations, Santy.e uses Google to identify exploitable web pages written in PHP which use the vulnerable functions "include()" and "require()".
Santy.e, however, also throws Yahoo's and AOL's search engines into the mix, learning a lesson from the originals, which were stymied when Google blocked their searches.
