So, have you enabled Remote Assistance on your Windows computer?
Or Remote Desktop?
Or do you have any version of VNC?
Or any other kind of remote or virtual desktop software?
Because ESET has discovered a nasty, nasty trojan that exploits exactly that kind of software. See this report at InformationWeek.com:
New Malware Puts Nasty Spin On Remote Control
Security researchers have discovered malware that scans PCs for remote-access or remote-desktop-configuration files, which indicates installed software that can be used to remotely control the computer. The malware, dubbed Georbot, then steals related credential files and transmits them to attackers, providing direct access to the machines using the built-in remote access tools.
http://www.informationweek.com/news/security/attacks/232602932
The cure is simple: when you’re not using Remote Desktop or Remote Assistance, disable it. Don’t run the VNC server on your PC or Mac except when you need it – really need it. Don’t leave this stuff fired up by default!
Of course, the real way people will learn caution in this matter is exactly the same way we learn everything else: bitter experience. Bitter, perhaps, for an individual and a home computer; catastrophic for, say, a health care provider. A word to the wise had better be enough.