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

A tunneling virus intercepts low-level OS interrupt handlers and antivirus hooks to write directly to disk, bypassing security software - it does not target internal file cavities.

A cavity virus identifies and overwrites empty cavities or null-padded sections within a host executable's structure, such as unused gaps between code sections. Because the virus occupies pre-existing free space rather than appending or prepending data, the infected file's total size remains identical to the original, making the infection invisible to tools that detect malware by monitoring file size changes.

A polymorphic virus mutates its own code signature with each replication cycle to evade signature-based antivirus detection - this mutation behavior is unrelated to physically fitting inside file cavities.

A stealth virus intercepts system I/O calls to return falsified original file data when read, hiding changes from the OS - it conceals modifications rather than installing itself within the file's internal spaces.