The new scam takes a different tack: It uses a Trojan horse that's seeded by tricking users into running a file that poses as something legitimate like a software update. Once on the victim's PC, the malware swings into action, encrypting a wide variety of document types -- ranging from Microsoft Word .doc files to Adobe Reader PDFs -- anytime one is opened. It also scrambles the files in Windows' "My Documents" folder.

Clicking on the alert downloads and installs FileFix Pro, but the utility is anything but legit. It will decrypt only one of the corrupted files for free, then demands the user purchase the software. Price? $50.

Users who have fallen for the FileFix Pro 2009 con do not have to fork over cash to restore their files, according to other researchers, who have figured out how to decrypt the data. The Bleeping Computer site, for instance, has a free program called "Anti FileFix" available for download that unscrambles files corrupted by the Trojan horse. And security company FireEye Inc. has created a free online decrypter that also returns files to their original condition.

See the original Computerware article