Jason Dion Security+ Course Practice Test 2025 - Free Security+ Practice Questions and Study Guide

The correct answer is a polymorphic virus, which is recognized for its capability to change its code each time it infects a new file or system. This self-encrypting feature makes it particularly challenging for traditional antivirus programs to detect and eliminate the virus, as it can modify its appearance to avoid signature-based detection methods.

Polymorphic viruses employ encryption to disguise their payload, using different encryption algorithms for each iteration. When the virus replicates, it could create a new variant with a different signature, making it hard for security solutions to recognize and combat the threat effectively. This adaptability not only enhances their longevity but also increases the complexity of developing countermeasures.

Other types of viruses like stealth, armored, and multipartite viruses have their own distinctive characteristics. For instance, stealth viruses often conceal their presence by hiding from antivirus software, armored viruses employ defensive measures to protect themselves from detection, and multipartite viruses can infect a system using various methods simultaneously. However, none of these types exhibit the self-encrypting behavior that is a hallmark of polymorphic viruses.