Definition: File viruses infect executable files by inserting their code into some part of the original file so that it can be executed when the file is accessed or they may overwrite the file entirely. File infecting viruses have targeted a range of operating system, including Macintosh, UNIX, DOS, and Windows.
Overwriting viruses cause irreversable damage to the files. Loveletter, which operated as an email worm, file virus, and Trojan downloader, is a notorious example of a file overwriting virus. Loveletter searched for certain file types and overwrote them with its own malicious code, permanently destroying the contents of those files. Files affected by an overwriting virus cannot be disinfected and instead must be deleted and restored from backup.
Also Known As: File infectors, virus
