logic bomblogic bomb
logic bomb - Computer Definition
Hidden code instructing a computer virus to perform some potentially destructive action when specific criteria are met.
A program routine that destroys data when certain conditions are met; for example, it may reformat the hard disk or insert random bits into data files on a certain date or if a particular employee record is missing from the employee database. Many viruses are logic bombs because they deliver their payload after a specific latency or when a trigger event occurs. See virus, latency and payload.