Path: utzoo!attcan!uunet!husc6!bloom-beacon!gatech!ncar!noao!arizona!naucse!wew From: wew@naucse.UUCP (Bill Wilson) Newsgroups: comp.binaries.ibm.pc.d Subject: Re: Are these binaries "safe"? Message-ID: <832@naucse.UUCP> Date: 10 Aug 88 15:27:57 GMT References: <299@babel.SanDiego.NCR.COM> Organization: Northern Arizona University, Flagstaff, AZ Lines: 30 From article <299@babel.SanDiego.NCR.COM>, by shehzad@babel.SanDiego.NCR.COM (Mevawalla Shezad): > In article <727@ns.UUCP> ddb@ns.UUCP (David Dyer-Bennet) writes: > To give you an example of how trivial it can be to write a virus, here is > something which is not exactly a virus but should give you some ideas as > to how they work. > > > Consider the instruction : MOV A,B (where A is the present address and B=A+1); > > This instruction reproduces itself and can devour all of memory if it is left > unchecked, eating up anything resident in memory. > Here is another one. Make a program that is to do trick directories. Actually make it look at the command.com and change all interrupt 37 to intterupt 38 thus changing all absolute disk reads to disk writes. You now have a nice disk eating facility that will stay until it is used on the hard drive or boot disk and thus destroys itself. You could make sure to make the program do something useful at the same time so that it doesn't look like a trojan. There are lots of ways to destroy a disk. Another one would be to write all over the partition table of a hard drive. Very easy to do and extremely destructive. Let your mind run free. You could probably think up all sorts of ways to destroy a disk. -- Bill Wilson (Bitnet: ucc2wew@nauvm) Northern AZ Univ Flagstaff, AZ 86011 {These views are mine and do not necessarily reflect those of my employer}