sub7 is a trojan not a virus
Virus
A program or code that replicates; that is, infects another program, boot sector, partition sector, or document that supports macros, by inserting itself or attaching itself to that medium. Most viruses only replicate, though, many do a large amount of damage as well.
Worm
A program that makes copies of itself; for example, from one disk drive to another, or by copying itself using email or another transport mechanism. The worm may do damage and compromise the security of the computer. It may arrive in the form of a joke program or software of some sort.
Trojan Horse
A program that neither replicates nor copies itself, but causes damage or compromises the security of the computer. Typically, an individual emails a Trojan Horse to you-it does not email itself-and it may arrive in the form of a joke program or software of some sort.
(usually comprised of a server and a client)
Polymorphic Virus
A virus that can change its byte pattern when it replicates; thereby, avoiding detection by simple string-scanning techniques.
Exploit
A program or technique that takes advantage of a vulnerability in software and that can be used for breaking security, or otherwise attacking a host over the network.
Bug
A programming error in a software program that can have unwanted side effects. Some examples include Various web browser security problems and Y2K software problems.
