Which virus can rewrite itself entirely before it tries to infect a file?

The metamorphic virus is designed with the ability to rewrite its own code every time it replicates itself. This self-altering characteristic makes it particularly challenging for traditional antivirus software to detect, as it can change its signature and evade detection algorithms. By redefining its structure while maintaining the same payload or functionality, a metamorphic virus can ensure that each instance appears unique, thereby increasing its chances of successfully infecting other files without being caught.

In contrast, stealth viruses use techniques to hide their presence but do not fundamentally change their structure with each iteration. Program viruses typically attach themselves to program files without changing their code, and multipartite viruses combine elements of both file infectors and boot sector viruses but also do not have the self-rewriting capability that characterizes a metamorphic virus.