76476.337@CompuServe.COM (Robert McClenon) (09/08/90)
A co-worker a few months ago had a problem that should be
mentioned. He picked up some free disks containing some installable
sound effects for a Macintosh. He knew that he should scan any
applications or desk accessories for viruses. It didn't occur to him
to scan sound effects. He installed them without using a virus
checker, although a commercial virus scanner was was installed. He
probably thought sound effects were harmless. (They are, unless they
have viruses.) Shortly thereafter he noticed that 75M of his 80M hard
disk was in use, and that the system and various applications had
increased in size. At this point he scanned for viruses and found
multiple infections by nVIR. The version of nVIR that he had picked
up was (like many subspecies of nVIR) extremely virulent and produced
very many copies of itself. An installable sound effect is of course
a resource, and on the Macintosh anything having a resource fork can
be infected by viruses. There would seem to be a moral to this: Check
everything, even things that you don't think are subject to viral
infections.
On the Macintosh, viruses are not limited to the System or
applications, but anything having a resource fork. On IBM-compatible
PC's, viruses can be not only in .COM and .EXE but in other types of
code such as .OBJ or .BIN.
Robert McClenon
Neither my employer nor anyone else paid me to say this.