Caller identification (ID) is a service that allows someone to see the phone number and sometimes the name or location of the person or business that is calling them on the phone. Caller ID spoofing is the act of fabricating a phone number to represent a caller. The false phone number will display on the recipient's caller ID, tricking the recipient into thinking that the call has originated from the fake phone number. Caller ID spoofing typically is associated with malicious activity.
The spoofing mechanisms of a caller ID are similar to those of email spoofing. Both types of spoofing falsify an originating source. They also can cause the recipient of communications to believe that they are interacting with legitimate contacts. However, they might, in fact, be communicating with strangers or even criminals.
One of the most popular ways to engage in spoofing is to use a web-based spoofing service. Using a web-based interface, callers will enter a source number, destination number and the number that that the caller wishes to appear on the recipient's caller ID. When this information is entered, a call will be placed to the source number, and when the call connects, the destination number will then be called. Some providers allow callers to enter the individual or company name that they want displayed on a caller ID, but many companies simply display the geographic region that is associated with the fake phone number's area code. Depending on the service, callers also might be able to record calls, send text messages or even change the way their voices sound.
Individuals who participate in caller ID spoofing also can use a telephone-based spoofing provider. Users of this particular service will pay for a personal identification number (PIN) in advance to use the service. Then, they can call a phone number provided to them by the spoofing service company and enter their PIN when prompted, followed by the fake phone number that they'd like to appear on a recipient's caller ID. After all of this information has been entered, the call will then be bridged and the call connected. In this way, telephone-based spoofing operates very similarly to how prepaid telephone cards work.
Despite having a history of illegal activity, caller ID spoofing also can be used for legal purposes. Collection agencies, private investigators and law enforcement representatives often use caller ID spoofing to accomplish their goals. Similarly, it can be used by business owners or employees to route calls accordingly or display relevant information. It also can help bridge the gap between proper landlines and Voice over Internet Protocol (VoIP) services that don't provide caller ID services.