1. Perpetrator

- The entity from the external environment that is taken to be the cause of a risk. An entity in the external environment that performs an attack, ie hacker.

-is the parlance of criminal justice, a suspect is a known person suspected of committing a crime.en.wikipedia.org/wiki/Perpetrator

2. Cyber terrorist

- a programmer who breaks into computer systems in order to steal or change or destroy information as a form of cyber-terrorism.

3. Cyber criminal

- are persons that committed crime using a computer and the internet to steal a person's identity or sell contraband or stalk victims or disrupt operations with malevolent programs.

http://thefreedictionary.com, www.tsl.state.tx.us/ld/pubs/compsecurity/glossary.html,