Almost certainly a shortened version of "WarGames dialer", from the film WarGames.

1. carrier scanner

2. A program which attempts to break a password of known length by iterating thru all possible combinations of characters that could make up that password.

This approach is not feasable for cracking most passwords these days. However, as late as the mid-1980s, some long-distance companies required only very short numeric access codes (e.g. five digits) to verify the identity of their customers. Wardialers were created which would, running unattended, call up long-distance providers' local connect numbers and iteratively try possible access codes. Codes which worked were logged for later illicit use.

These wardialers had a high success rate because of the small range of possibilities to iterate through, e.g. 10000 for a five digit access code, compared to hundreds of trillions of combinations for an eight-character alphanumeric code.

Long-distance providers soon required longer passwords and took advantage of technology for rapidly tracing the phone numbers that wardialers were being run from, such that running wardialers became pointless and dangerous.
References in periodicals archive ?
Finding an ATM to call is not hard, as even a primitive "wardialer" - basically a machine that calls thousands of numbers at a time - can find ATMs, which often use dial-up connections.
A la par, la seguridad logica dio pasos enormes gracias a la aparicion de nuevas amenazas que ya no solo se refieren a los virus y codigo malicioso, sino a la aparicion del robo de ident idad, escaneo de puertos, wardialers, exploits, control remoto de equipos, backdoorsy fraude informatico, entre otros.