(ISC)2 Certified in Cybersecurity Practice Exam

A worm is a type of malware designed to replicate itself and spread to other systems independently, without needing any user action. It operates by exploiting vulnerabilities in software or network protocols, enabling it to propagate across networks, often resulting in widespread disruption.

Worms can infiltrate systems through various means such as email attachments, infected files, or network vulnerabilities. Once a worm is inside one system, it will scan for other systems on the network to infect, continually replicating itself and exacerbating its spread. This self-propagation capability sets worms apart from other types of malware, such as viruses, spyware, or Trojan horses.

In contrast, a virus requires a host file to attach itself to and generally requires user action to activate, such as opening a file. Spyware collects data without the user's knowledge but does not have the ability to replicate and spread. A Trojan horse, while it can provide unauthorized access, disguises itself as legitimate software and relies on user interaction to be executed, meaning it cannot spread autonomously. This distinct characteristic of self-replication and propagation makes worms a significant threat in cybersecurity.