What is a companion virus?
A COMPANION virus is one which, instead of modifying an existing file, creates a new program which (unknown to the user) gets executed by the command-line interpreter instead of the intended program. (On exit, the new program executes the original program so that things will appear normal.) The only way this has been done so far is by creating an infected .COM file with the same name as an existing .EXE file. Note that those integrity checkers which look only for *modifications* in *existing* files will fail to detect such viruses. (Note that not all researchers consider this type of malicious code to be a virus, since it does not modify existing files.
A COMPANION virus is one that, instead of modifying an existing file, creates a new program which (unknown to the user) is executed instead of the intended program. On exit, the new program executes the original program so that things appear normal. On PCs this has usually been accomplished by creating an infected .COM file with the same name as an existing .EXE file. Integrity checking antivirus software that only looks for modifications in existing files will fail to detect such viruses.
A COMPANION virus is one that, instead of modifying an existing file, creates a new program which (unknown to the user) is executed instead of the intended program. On exit, the new program executes the original program so that things appear normal. On PCs this has usually been accomplished by creating an infected.COM file with the same name as an existing .EXE file. Integrity checking antivirus software that only looks for modifications in existing files will fail to detect such viruses.
Related Questions
- If a companion animal is suspected to have highly pathogenic H5N1 avian influenza virus infection, how should the premises be disinfected?
- If highly pathogenic H5N1 avian influenza virus infection is suspected in a companion animal, when should I report it, and to whom?
- How can companion birds become infected? Can they spread the virus?
