[comp.virus] MSDOS viruses

lr@cs.brown.edu (Luigi Rizzo) (02/03/91)

Hi there,
a question just to point out how things are.  Suppose the following
scenario:

Given an MSDOS machine with an infected HARD DISK (no matter what
kind of virus it is), and a sane floppy disk, I do the following:

1) Boot with a sane floppy disk;
2) SYS C:
	boot sector, IBMBIO.SYS, IBMDOS.SYS and COMMAND.COM
	are restored from the sane disk.
3) REN C:\CONFIG.SYS C:\CONFIN.OLD
4) REN C:\AUTOEXEC.BAT C:\AUTOEXEC.OLD
	avoid any infected driver/utility/whatever be called at
	startup
5) Reboot from the hard disk.

At this point, am I sure that the virus cannot be installed in
the PC, and that I can execute the 'internal' DOS commands ?

	Thanks
Luigi Rizzo
lr@cs.brown.edu, luigi@sssup2.sssup.it