ANI SPOOFING – What is it?

July 27, 2016

Have you ever received a phone call from a number that looks familiar, or similar to your own, and answer the call only to find out that it’s a telemarketer? If so, chances are you’ve been a victim of ANI spoofing.

Better known as Caller ID, ANI stands for Automatic Number Identification in the Telecommuncations industry. ANI spoofing is the act of changing ANI information to a number other than its original form, ususally with the intent to trick consumers. The FCC defines illegal ANI spoofing as deliberately causing any caller identification service to transmit or display misleading or inaccurate caller identification with the intent to defraud, cause harm or wrongfully obtain anything of value.

Is ANI spoofing illegal? Yes, if the intent in doing so is to defraud, cause harm, or wrongly obtain anything of value. Nevertheless, ANI spoofing has flourished with the introduction and growth of IP networks in the telecommunications marketplace which can make it nearly impossible to identify the true source of ANI manipulation. Not long after caller ID was introduced to the world and the internet started to gain popularity, spoofing websites began popping up so that anyone could change caller ID on any phone call. You could send your friend an official call from the White House! It didn’t take long for the fraudsters to figure out how to use that technology to their advantage.

So why spoof caller ID? It is often used to trick someone into revealing personal information to be used for fraudulent activity. Telemarketers also use the method to trick consumers into answering calls they would otherwise ignore. Here are some additional use cases for ANI spoofing:

  • Fraudulent companies pose as our financial institutions, the IRS, or the FBI, attempting to extort personal information, credit card numbers, money, even iTunes cards.
  • Some questionable companies manipulate caller ID to reflect the same NPA/NXX as the dialed number, counting on us to think it’s a local call and we must therefore know who it is. So we answer. Sometimes the number on the caller ID is an exact reflection of our own phone number, and who doesn’t want to answer that call just out of pure curiousity?
  • Immigration officials warn that scammers pose as U.S. Citizenship and Immigration Services or another government agency. Scammers threaten deportation if the called party doesn’t pay. The caller may ask for a social security number, passport number or other personal information.
  • Caller ID spoofing has been used in “swatting” attacks, where a caller falsely reports an emergency to public safety with the intent of getting a SWAT team to the site. The caller may report a shooter or hostage situation to which law enforcement would send large presence to the site. SWAT teams have pulled guns out on the innocent, surprised victims and the cost of this response is astronomical.
  • ANI spoofing has also been associated with Telephone Denial of Service (TDOS) attacks and traffic pumping through hacked PBXs.

Inteliquent does not engage in any form of illegal ANI spoofing and reports all complaints of such activity to the upstream carriers that included illegal spoofed ANI. However, carriers have an obligation to protect the privacy of their customers and when investigating allegation of illegally spoofed ANI, carriers must consider thorny legal issues as to how to lawfully disclose such information. Moreover, it is the responsibility of each carrier in the call chain to take appropriate action with respect to calls that include illegally spoofed ANI. In many cases the trail goes cold as carriers are unable to keep up with the volume of reports of illegally spoofed ANI, while also addressing call completion issues which are a clear priority over ANI manipulation.


It’s fair to say that Randy has grown up at Inteliquent with 11 years of service and various positions under his belt. He stays in shape by running marathons and riding his bike to work during the summer.


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