A payload refers to the component of a computer virus that performs a malicious activity. In addition to the speed at which a virus spreads, the threat level of a virus is calculated by the damage it causes. Viruses with stronger payloads tend to be more harmful.

While not all viruses have a payload, some payloads are considered extremely dangerous. Some examples of payloads are data destruction, offensive messages, and delivery of spam emails via the infected user's account.

A payload is also known as a destructive payload.

Some viruses copy themselves from one computer to another. Other viruses can steal data or files, allow wiretapping or unauthorized access, destroy data and cause other consequences. It is also possible for a virus to carry multiple payloads.

Current malware is less likely to embed a payload that damages system files; instead, they allow backdoor access to a user's computer and the theft of sensitive information.

Some of the ways to perform a payload include:

• Using an unprotected computer (computer without antivirus installed) connected to a network
• By starting the computer using infected removable media
• Opening an infected file
• By running an infected program
• Activating a logic bomb