A virus that attempts to install itself inside the file it is infecting is called?

A tunneling virus intercepts operating system and antivirus interrupt calls to bypass security hooks, not to hide code inside file cavities.

A cavity virus, also called a space-filler virus, targets empty or unused sections within an executable file and inserts its malicious code there. Because the file size does not change, it is harder for signature-based scanners to detect. This technique of hiding inside existing file cavities is the defining characteristic of this virus type.

A polymorphic virus mutates its own code on each infection to evade signature detection, rather than targeting unused space within a host file.

A stealth virus hides its presence by intercepting OS read requests and returning clean data, which is an evasion technique unrelated to file cavity insertion.