StopBadware.org, a group that acts as a "neighborhood watch" initiative against spyware and other malicious software programs, recently threw down the gauntlet against a site that distributes what the group calls "one of the worst \[malware applications\] we've seen--and we've seen a lot."

The offender, FastMP3Search (located at fastmp3search.com.ar), offers a browser plug-in that supposedly helps people locate MP3 audio files. However, the plug-in does much more than simple MP3 searches. According to StopBadware's analysis the plug-in secretly disables Windows Firewall and downloads several other malware packages, including adware, Trojan horses, and a browser hijacking tool. Those applications in turn download even more malware. To make matters even worse, the plug-in changes the Windows hosts file to prevent access to certain security vendor sites, such as those that belong to McAfee and Symantec. StopBadware goes on to say that the plug-in is also difficult, if not impossible to uninstall.

"In the past year, we've come across dozens of malicious programs available on hundreds of web sites, and without question, the FastMP3Search.com.ar Plugin tops our list of the worst actors," said John Palfrey, co-director of StopBadware.org and executive director of the Berkman Center for Internet & Society at Harvard Law School.

In response to the plug-in's behavior, StopBadware decided to join forces with the Center for Democracy and Technology (CDT) to file a formal complaint with the US Federal Trade Commission (FTC) against FastMP3Search.

"The reason why we are issuing such a critical report on the FastMP3Search.com.ar Plugin and filing this complaint with the FTC is because they've combined so many bad things in a single bundle. It's a parade of horribles. Most notably, the application disables a user's firewall automatically without informing the user. We recommend that users do not download the FastMP3Search.com.ar Plugin, and we urge the FTC to take action to protect consumers from this bad application," Palfrey concluded.

StopBadware.org said that it's "the largest consumer protection initiative" acting in this particular arena. The group is led by the Berkman Center for Internet & Society and Oxford University's Oxford Internet Institute. Consumer Reports WebWatch serves as an unpaid special advisor and the group is supported by several notable technology companies, including Google, Lenovo, and Sun Microsystems.