The ubiquitous Caller ID hasn’t changed much over the years, but the technology to exploit it has exploded. That may be about to change.
Fraud and abuse in the form of robocalling, and more specifically illegally spoofed calling, is the No. 1 consumer complaint to the Federal Communications Commission (FCC). Robocalls make up nearly half of all phone calls, so frustrated consumers simply don’t answer incoming calls and businesses can’t get through to customers when they need to reach them.
At the root of the problem is the ease of spoofing caller IDs. Anyone can spoof their outbound Caller ID by using an online service like Spooftel or SpoofCard. These services are meant to protect the caller’s number from being displayed and claim they aren’t intended for malicious purposes, but the fact that they exist indicates the breadth of the problem.
For cybersecurity professionals, Caller ID spoofing is a particularly pernicious problem. To gain the trust of their intended victim, hackers hide behind a friend, company, or institution associated with their target’s information. Typically, they will find a trusted number and spoof it.
Caller identifications are determined during the second ring of a call. In this short period, spoofers use frequency shift keying to alter the binary format of the number, a process that can be automated. Current Caller ID technology was developed without any consideration that it could be used nefariously and hasn’t changed much, while the technology to exploit it has exploded.
The FCC Steps in with SHAKEN and STIR
FCC chairman Ajit Pai challenged the telecommunications industry in November 2018 to adopt a caller authentication system to combat this growing nuisance or face regulatory intervention. This has spurred the telecommunications industry to develop a framework of interconnected standards called SHAKEN (Secure Handling of Asserted information using toKENs) and STIR (Secure Telephony Identity Revisited) that defines how telephone service providers should work together to ensure calling numbers have not been spoofed.