A computer virus is a type of malicious code that attaches itself to legitimate programs or files and spreads when the infected file is executed by a user.
Characteristics:
- Requires human action to spread (e.g., opening a file or running a program).
- Can modify or delete files, corrupt data, or render systems unusable.
- Often spreads through email attachments, infected software, or USB drives.
Example:
The ILOVEYOU virus (2000) spread via email and caused billions of dollars in damage by overwriting files and mailing itself to users’ contacts.