Two Year Old Malware Infects Thousands of Office Printers
Trojan.Milicenso, as the culprit is called, compromises computers via traditional means, such as through email attachments and/or visiting websites hosting malicious scripts. In the case of the latter, it usually occurs when an office worker clicks on a link in an unsolicited email, thus breaking one of the cardinal rules of common sense computing practices.
Image Source: Flickr (leokoivulehto)
Once infected, the Trojan creates a heavily encrypted DLL file that makes it difficult to detect. It then gets busy gathering data and sending it back to a remote hacker, which is the real threat here. An annoying side effect, however, is the creation of what appears to be a common printer spool file (it's actually an executable) that triggers print jobs of garbled text.