What is War dialing?

What is War dialing?

War dialing is a technique to automatically scan a list of telephone numbers, usually dialing every number in a local area code to search for modems, computers, bulletin board systems  and fax machines. Hackers use the resulting lists from whole block of phone numbers for various purposes: hobbyists for exploration, and crackers - malicious hackers who specialize in breaching computer security - for guessing user accounts or locating modems that might provide an entry-point into computer or other electronic systems. It may also be used by security personnel, for example, to detect unauthorized devices, such as modems or faxes, on a company's telephone network.

There are number of war dialers available from last few years, some are illegal and some are not updated from long time. The classic DOS based utility is a golden standard in war dialing utility. THCscan, phone-sweep, phone-scan are other popular tools used from last few years.

In some senses, war dialing is like the predictive dialing used in call centers. However, where the aim in call centers is to find human respondents for actual telephone conversations, war dialers are generally used to find electronic lines of communication, either to penetrate systems, as mentioned above, or to aid in network security by identifying unprotected modems and adding security.

New types of war dialing software may allows users to get more information on the many phone numbers on a call list. Speech recognition software can help these automatic dialers to get more data about all of the numbers in a given set, and this valuable data can be important to users. However, some U.S. legislation has curtailed the practice of war dialing by making certain kinds of "dial for tone" programs illegal.

Below SANS white paper will give the reader general information on war dialing, war dialing tools and general steps you can take to protect your network from unwanted intruders who may try to gain access to your network via unauthorized or poorly managed modems.

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