CHESS@YKTVMV.BITNET (David.M.Chess) (04/11/91)
In an otherwise quite solid article, William Hugh Murray <0003158580@mcimail.com> writes: >>d. That the individual is sufficiently sophisticated to avoid leaving >>obvious clues (file sizes, dates, etc.). > >Well, that excludes all viruses. It is possible to conceive of a >virus that was so subtle that it left no evidence; on the other hand, >if you never notice that you have been damaged, then you have not been >damaged. > >No such virus has ever been detected, for obvious reasons. All the >reported viruses have done something noticeable. Since the intent of >a virus is to spread, and since if it has no symptoms, the author >cannot know if it is successful, few people would write such a virus. This is much too strong. There are certainly viruses that go to great lengths to avoid leaving *obvious* clues, and there are quite a number of viruses that have no intentional payload (don't ever erase files, damage data, print a message, or anything else). Presumably the authors of these viruses had a somewhat different set of intents; any statements of the form "the intent of a virus is X" are backed up by little or no evidence, and should be avoided by the fastidious! *8) Of course, all viruses have *some* symptoms (they change existing objects, or create new objects, or whatever). But that doesn't mean that there aren't viruses that do their best to have as few symptoms as technically feasible. Even a virus that did have a destructive "payload" could be written to have no obvious symptoms until the payload was delivered. DC