Worms

In short: A worm is malware that spreads on its own across networks or e-mail to other systems.

In more detail: Unlike a virus, a worm needs no host file and no user action. It uses security holes or sends itself.

In Depth

Well-known worms

• Morris worm (1988): one of the first, knocked out thousands of Unix computers.
• ILOVEYOU (2000): spread by e-mail and overwrote files.
• Blaster, Sasser, Conficker: used Windows vulnerabilities.
• WannaCry (2017): ransomware worm via EternalBlue, see WannaCry.

Consequences

Network overload (network overload), data loss, introduction of further malware.

Protection

Install patches, firewall, network segmentation, switch off unnecessary services.

See also: E-mail Worms, Malware, Trojans, WannaCry