Information Services

West Chester University

Adel Barimani, CIO
Vice President for Information Services
Anderson Hall Room 23
West Chester University

Virus FAQ

What Are Viruses?

The term Virus is used by many people to mean many things.  In computers, a Virus is a program or piece of a program that executes on a victims computer without the knowledge of the victim.  There are 4 types of computer viruses, File, Boot, Macro, and Network viruses.

File viruses infect real programs that are installed in the computer, create file doubles, or uses "features" that are built into the system.  Boot viruses infect the computer's disk drive where the computer gets instructions on how to start up the computer.  Macro viruses are stored in documents, spreadsheets, or other files of popular packages such as Microsoft Word.  Finally, network viruses spread themselves over the local network or over the Internet using protocols such as email.

One virus could actually be designed using one or more of the above virus types.  The virus spreads itself based on the type of virus.   The viruses have multiple methods of "living" inside a computer.  TSR virus will stay in the computers memory while the computer is running.  These viruses tend to intercept commands and messages the computer is processing.  Stealth viruses are designed to hide themselves from the victim.  Polymorphic and Self-Encrypting viruses are harder to detect.  These viruses change themselves every time they execute.  This makes it difficult for virus scanners to look for a virus's "fingerprint."

Finally, all viruses have some type of destructive capability.  Some could actually be harmless.  Other viruses use up a small amount of computing resources.  Dangerous viruses may seriously disrupt computer use.  Very Dangerous viruses may do just about anything to the victim's computer, including deleting files, erasing hard-drives, or change how programs work.

What can viruses infect?

  • Program files, non-file areas used on computer start up (boot sectors), and data files with macro capabilities
  • Data disks and disks used to transfer programs
  • Downloading of files from an online service, i.e. internet
  • A file attachment from an email message

What do viruses not infect?

  • Hardware, such as keyboards and monitors, graphic files, data files without macro capabilities, software items other than program files
  • Write protected disks
  • Your computer when you read messages from an online service, i.e. internet
  • Text-based email messages. For small messages, it is best to "cut and paste" onto the body of the email message rather than sending it as an attachment