Using a computer to dial telephone numbers within a given range, usually with the intention of finding a modem carrier signal. The practice largely predated the widespread penetration of broadband Internet connectivity; at the time, many businesses, agencies, and individuals operated computer systems "on-demand" through telephone-based modems, each of which might (or might not) offer a unique (and possibly privileged) selection of information, as well as possibly offering access to powerful hardware or a platform for reaching other networks and systems. Usually, the wardialer
would be covertly planted on a public, shared, or corporate phone line, left to operate for a limited time, then retrieved so that any "positives" (phone lines returning a modem carrier signal) could be investigated later from yet another location. The practice often went hand-in-hand with phreaking
, for obvious reasons.
Today, some telemarketing and social research firms use similar programs (usually working from a digital phone book) to reach residential numbers in search of sales or social information. Also, on rare occasions, people engaged in social engineering
have used a form of this process to explore "gaps" in corporate phone listings to discover (and identify the owners of) unlisted numbers.
This term directly inspired the term wardriving
, due to similarities between the two practices: both return unpredictable results, both require real-world travel, and both activities are done for rather similar reasons. On the other hand, while wardriving is inherently focused on and limited to a specific geographic area, wardialing is a prototypical bruteforce
process, much like password cracking, and can theoretically be achieved from any location with a dial tone.
In the 1983 movie Wargames, a teenager engages in wardialing and discovers a backdoor
into the NORAD (NAADS
) computer system. He then accidentally runs a simulation which almost turns into World War III
The wardialer is dead. Long live the wardriver.