More than 1,000 computers on Cornell's networks have been infected by new "bot" computer viruses that have the potential to infect all Windows computers on campus. Macintosh computers running Windows are also susceptible.

This new threat spreads when infected removable devices, such as thumb or flash drives, music players, cell phones, cameras, external drives and the like, are connected to the USB port of a Windows computer. If you have used any removable devices with your Windows computer this month, there is a reasonable chance the computer has been infected, even if you don't notice any difference in how it is running, the Cornell IT Security Office announced. You do not have to be logged in as an administrative user for infection to take place, they added. At this time, Symantec AntiVirus does not fully protect against this threat; even if Symantec reports that it has cleaned up the virus, you may still be infected, the Security Office warned.

A number of Cornell departments are sponsoring walk-in clinics where USB devices can be checked and cleaned. According to the Security Office, about 15 percent of devices brought inj so far have been found to be infected.

You also can make your computer immune to catching this virus from USB devices by disabling the Windows autorun feature. The Security Office recommends disabling the autorun feature permanently. This type of malware will continue to appear, they said.

When a bot takes over your computer, whoever is controlling the bot can download more malicious software, steal information from you, and use your computer to attack other systems on the Internet -- all of which has been seen in systems infected at Cornell. Botnets, a set of computers all being controlled by the same people, are often operated on behalf of international organized crime, so these infections need to be taken seriously.

Detailed information and instructions, including clinic locations, can be found at http://www.cit.cornell.edu/security/alerts/usb-bot/, or contact the help desk at 607-255-8990 or helpdesk@cornell.edu.