Penetration Testing and Network Defense

A self-replicating piece of software, usually written with malicious intent, that propagates by infecting another program. It cannot run independently of the program in which it resides, and its host program must be executed explicitly to activate the virus.

Virtual private network. A way of using a public telecommunications infrastructure, usually the Internet, to create a secure communications channel that remote users can use. It uses cryptographic tunneling protocols to provide confidentiality, authentication, and integrity of the data transmitted.

Software designed to take the work out of penetration testing by scanning target systems and comparing them against known vulnerability signatures.