Backdoor
From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide
A backdoor, in computer terminology, is a programmed exploit that permits remote access into a computer system, usually at a level of total control.
Backdoors were installed by Cylon agents in Gaius Baltar's Command Navigation Program which permitted the Cylons to remotely deactivate ships during the Fall of the Twelve Colonies, allowing them an easy victory against their creators on the Twelve Colonies.