avenger@runx.ips.oz (Troy Rollo ) (07/24/88)
I was recently asked to consider this problem. The easiest solu- tion I came up with was to write a Virus Immunisation Program (VIP) which calculated cyclic redundancy check numbers for each file on a given device and stored these numbers on a safe medium prior to backup. Regular checks could be made using the VIP, and if the CRC on any program (exe- cutable, source, object or script) does not match (and should not have been modified) the suspect file should be restored from the backup medium. Precautions: 1) The machine should never automatically boot from the hard disk. The operating system on that disk may be infected, and if you subsequently run your backup program or VIP, they may become infected. 2) The machine should be turned off before running either the backup program or the VIP for much the same reasons as (1). 3) Along the same lines as (1) and (2), the backup program and VIP should be contained on separate floppy disks, each with its own operating system. ---------------------------------------------------------------- Internet: avenger@runx.ips.oz.au UUCP: uunet!runx.ips.oz.au!avenger "Watch out for Gobbledocks - they'll steal all your silicon chippies"