A Verified SIP Header
Here’s how the verstat token looks inside the SIP when a caller is certified to be who they claim to be:
The different values for verstat within the PAID (P-Asserted-ID) are:
- TN-Validation-Passed
- TN-Validation-Failed
- No-TN-Validation
Below is an example of the Identity Header when verified by your terminating service provider:
3Nwb3J0IiwieDV1IjoiaHR0cHM6Ly9zaGFrZW4uc3BlY3RydW0uY29tLzRkNjV
lZmRiOGExY2EzNjZlOTU3NmM4ZmRhNzQ3ZmE0LnBlbSJ9.eyJhdHRlc3QiOiJB
IiwiZGVzdCI6eyJ0biI6WyIxMjA3NTIxNTAxNiJdfSwiaWF0IjoxNjkwOTQzND
Y4LCJvcmlnIjp7InRuIjoiMTIwNzQwMzk0MzQifSwib3JpZ2lkIjoiYTI3ZWU1
NjQtMmNmNC00NzQ3LWFjMzQtNzBhOGE0ZWEyZTkyIn0.z2fki3r_YUnvAbwj5A
1xu-DWDTNql-7zH6lmetYuqL82BreWtZVSZh7Ax1y2SG-zn1FZGSdU0yDfcvcv
1MTD1w;info=<https://shaken.spectrum.com/4d65efdb8a1ca366e9576
c8fda747fa4.pem>;alg=ES256;ppt=shaken
This can be analyzed to determine that the PASSporTs in the call are tied to the certificate belonging to the carrier.
You’ve Heard This Before…
In Order to Improve Something, First You Need to Measure It
First step for enterprises is to measure which calls, coming into their contact centers, are RoboCalls and which are not. It’s easily done. Even if your carrier doesn’t provide you with these reports.
Solution
You don’t want to block those calls. It may be a sales opportunity.
Identify the robo calls and route them either to a CAPTCHA server, or to agents trained on social engineering techniques.
Conclusion
According to TU, 73% of consumers say they have not answered calls because of concerns about safety or fraud. 58% of consumers say that in the past three months, they have missed important calls because they could not immediately identify the caller. Only 10% of phone calls are actually answered.
STIR/SHAKEN, the mechanism to ensure a caller is certified to be who they claim to be is now in place. Abuses and poor implementations exist. Attestation policies are not yet consistent. But if we start now to measure and analyze which calls are certified and which calls are not certified, we can reclaim our phone network.