Google's free online newsgroup Google Groups hosts plenty of harmless user-generated content. But like any service that allows users to post information, it also turns out to be useful for "misuser-generated content."

A Symantec security researcher has found that Trojan malware is using Google Groups to fetch commands for directing its attacks.

"A back door Trojan that we are calling Trojan.Grups has been using the Google Groups newsgroups to distribute commands," said Symantec security researcher Gavin O Gorman in a blog post on Friday. "Trojan distribution via newsgroups is relatively common, but this is the first instance of newsgroup [command and control] usage that Symantec has detected."

The Trojan is designed to request a page from escape2sun, a private newsgroup. The page lists instructions for the malware: an index number, a command line to execute, and, optionally, a file to download. The newsgroup also stores responses from the infected host. Commands and responses are encrypted, to conceal the information.

The Trojan itself doesn't appear to be particularly sophisticated. The fact that the private newsgroup containing the commands is in simplified Chinese and the fact the stored commands include references to the .tw domain suggest the author(s) designed it to operate in Taiwan.

Google, not surprisingly, frowns on this sort of thing.

"Using Google Groups, or any Google product, in this way is a violation of our product policies," said a Google spokesperson in an e-mail. "We take various actions, including shutting down accounts, to enforce these policies."

Indeed, it appears that Google has taken steps to shut the account.

Based on statistics gathered about the Trojan's distribution and the presence of several debugging strings in the malware code, O Gorman speculates that the Trojan is a prototype that's undergoing testing.

"The low numbers imply this is a discreet Trojan, used to subtly gather information and potentially determine future attack targets," he explains. "In addition, there is no attempt within the DLL to maintain persistence on the attacked computer, further evidence of a Trojan attempting to remain undiscovered. Such a Trojan could potentially have been developed for targeted corporate espionage where anonymity and discretion are priorities."

InformationWeek has published an in-depth report on the public cloud, digging into the gritty details of cloud computing services from a dozen vendors. Download the report here (registration required).