About Viruses and Worms

Computer viruses are self-reproducing programs that use various methods of transmission to spread infection from computer to computer.

  • Executable viruses are spread by running infected programs.
  • Macro viruses are spread by opening, saving, and printing infected document files.
  • Boot-sector viruses are transmitted from machine to machine on infected disks. Any attempt to boot a machine from an infected disk can spread the virus, even if the attempt is unsuccessful.

Worms hack into computers through missing security patches and then use those computers to hack other computers.

Avoiding Infection

Most common viruses are spread through email and sharing files. Worms are spread when secure computing practices are not followed (see Security Overview).

To prevent the spread of computer viruses and worms, ITS recommends that you install and maintain antivirus software. ITS offers free downloads of Sophos Endpoint Security for Windows (Vista/7/8.1) and Macintosh OS 10.5 – 10.9. These virus protection programs are available to members of the USC community on the software download page.

If you believe your system has been infected by a virus, see Removing a Virus.

Additional Information

If you would like more in-depth information about viruses and information security, visit the websites below.

Getting Help

ITS Customer Support Center provides support for software available on the software download page. For help with other programs, contact the software’s vendor or go to the vendor’s website.

For questions, please contact the ITS Customer Support Center.