Logic Bomb

A logic bomb is a program or code fragment which triggers an unauthorized, malicious act when some predefined condition occurs. The most common type is the “time bomb”, which is programmed to trigger an unauthorized or damaging act long after the bomb is “set.” For example, a logic bomb may check the system date each day until it encounters the specified trigger date and then executes code that carries out its hidden mission. Due to the built-in delay, a logic bomb virus is particularly dangerous because it can infect numerous generations of backup copies of data and software before its existence is discovered.