Wiktionary
n. A piece of code intentionally inserted into a software system that will set off a malicious function when specified conditions are met.
WordNet
n. a delayed action computer virus; a set of instructions surreptitously inserted into a program that are designed to execute (or `explode') if a particular condition is satisfied; when exploded it may delete or corrupt data, or print a spurious message, or have other harmful effects; "a disgruntled employee planted a logic bomb" [syn: slag code]
Wikipedia
A logic bomb is a piece of code intentionally inserted into a software system that will set off a malicious function when specified conditions are met. For example, a programmer may hide a piece of code that starts deleting files (such as a salary database trigger), should they ever be terminated from the company.
Software that is inherently malicious, such as viruses and worms, often contain logic bombs that execute a certain payload at a pre-defined time or when some other condition is met. This technique can be used by a virus or worm to gain momentum and spread before being noticed. Some viruses attack their host systems on specific dates, such as Friday the 13th or April Fools' Day. Trojans that activate on certain dates are often called " time bombs".
To be considered a logic bomb, the payload should be unwanted and unknown to the user of the software. As an example, trial programs with code that disables certain functionality after a set time are not normally regarded as logic bombs.
Usage examples of "logic bomb".
Looking back, he sees Raven riding out toward the Street, the logic bomb glowing a soft blue, like heavy water in a reactor.
They hadn't put all their faith in the logic bomb to keep the Navy from intervening while their coup went on.
It seems they were attempting to set up a domino contagion or a logic bomb, perhaps to prevent override by prefix code.
You ought to see their faces when Kluge drops a logic bomb into their work.