Path: utzoo!utgpu!water!watmath!clyde!bellcore!rutgers!ucsd!ucbvax!hplabs!hp-sdd!ncr-sd!babel!shehzad From: shehzad@babel.SanDiego.NCR.COM (Mevawalla Shezad) Newsgroups: comp.binaries.ibm.pc.d Subject: Re: Are these binaries "safe"? Message-ID: <299@babel.SanDiego.NCR.COM> Date: 9 Aug 88 21:29:10 GMT References: <4774@csli.STANFORD.EDU> <30587@clyde.ATT.COM> <8475@ihlpb.ATT.COM> <727@ns.UUCP> Reply-To: shehzad@babel.SanDiego.NCR.COM (Mevawalla Shezad) Organization: NCR Corporation, Rancho Bernardo, CA Lines: 17 In article <727@ns.UUCP> ddb@ns.UUCP (David Dyer-Bennet) writes: >believe in viruses in theory, and I believe that they exist in >pracice, but I've never actually seen any evidence for their >existence. 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. This should make a believer out of you non-believers!