Fake Caller ID

How Does Caller ID Spoofing Work?

Caller ID is spoofed through a variety of different methods, with the most common ways of spoofing Caller ID are through the use of Voice over IP and/or PRI lines.

Another method involves emulating the Bell 202 FSK signal. This method, called orange boxing, uses software that can generate the audio signal that can be coupled to the telephone line during a telephone call. The object is to deceive the called party into thinking that there is an incoming call waiting from the spoofed number, when in fact there is no incoming call. This technique often involves an accomplice who may provide a secondary voice to complete the illusion of a call waiting call. Because the orange box cannot truly spoof incoming caller ID prior to answering, and relies on the guile of the caller, it is often considered as much a social engineering technique as it is a technical hack.

Other methods include: switch access to the SS7 network; and social engineering telephone company operators who place calls for you from the desired phone number. Another method that is not used as often is VXML.

Why Would I Want to Fake My Caller ID?

It seems as though many of the reasons one would want to give use fake caller ID are unscrupulous, there are many legitimate uses too. Large companies use it for their call centers and telemarketing departments. Private investigators and bail bondsmen use it to investigate people and to locate people who have skipped out on their bonds. Individuals might want to display their home or work number when not calling from those locations, such as a small business owner calling clients from a cell phone; they may not want their cell phone number to show up on caller ID. There is a gray area in regards to using caller ID spoofing for practical joke reasons, just keep in mind that all calls are logged somewhere and they can be traced back to originating caller number and location. For a more indepth look at uses for Caller ID spoofing, see our usage guide