p1@rlyeh.wimsey.bc.ca (Rob Slade) (12/08/90)
tfarrell@lynx.northeastern.edu writes: > I use a program on my hard drive called LZEXE. It is a shareware There are a number of these programs. > though, is that it includes a self-check into every file compressed > with the utility, so that if the file has been changed it will notify > you. This would detect the presence of a virus in the software. There are a couple of problems with this. One is that if you compress an infected program, you end up with a compressed, infected program. The second is that, as with the discussion on CRC checkers earlier, a stealth virus simply "lies" to any checking or authentication routine. One additional problem is that programs which already have "self chekcing built in will fail because of the compression and addition of the decompression module.