Phreaker

the skilled saboteur who relies on guile and the fallibility of employees in an information system.  Employees do not necessarily have to be co-conspirators.  The phreaker takes advantage of their innocence and trusting nature.  The term is used in contrast to a hacker and a cracker.  A hacker is a person who relies only upon technology to hack into the system (e.g., by breaking the encryption code.)  Whereas a hacker usually breaks in without intention to harm the system or for personal gain, a "hacker" turns into a "cracker" when the intention becomes more sinister.  A "phreaker" may do some hacking or cracking, but the to be a phreaker the saboteur must also rely upon human fallibility.  (See also firewall.)