CyberGuard dictionary / Malware
Computer Worm
A computer worm is self-replicating malware that spreads to other systems without needing to attach to a host program.
In simple terms
A worm can move through a network or shared service after finding a route to another device.
Technical explanation
Worms may exploit reachable vulnerabilities, weak credentials, or exposed shares to copy and run themselves. Their propagation can rapidly increase load and broaden an incident even if the original payload is simple.
Automated propagation can outpace manual response when many reachable systems share the same weakness. Network isolation, patching, and credential changes may all be needed to interrupt its spread.
Examples in practice
One infected computer scans nearby devices for a vulnerable service and automatically copies the worm to each one it reaches.
A vulnerable service exists on three network segments. Isolating the first infected device is insufficient until the team blocks the propagation path and updates the other reachable systems.
Why it matters
Fast spread makes early isolation and patching of reachable systems especially important.
VERIFY & LEARN MORE
Sources and further reading
- learn.microsoft.comhttps://learn.microsoft.com/en-us/defender-xdr/criteria↗
- csrc.nist.govhttps://csrc.nist.gov/pubs/sp/800/61/r3/final↗
Published 2026-10-15 · Last updated 2026-10-15 · CyberGuard editorial content. Source links provide context; they do not imply endorsement.