What strategies are in place to prevent phone number spoofing for outbound calls?
Posted: Mon May 26, 2025 9:05 am
Phone number spoofing—where a caller deliberately falsifies the phone number displayed on the recipient’s caller ID—is a significant challenge in telemarketing and outbound calling. It can damage trust, harm brand reputation, and lead to regulatory penalties. To combat spoofing, organizations implement multiple layered strategies combining technology, policy, and compliance measures. Here are the key strategies commonly employed:
1. Implementation of Caller ID Authentication Protocols
A primary defense against spoofing is adopting industry-standard caller ID authentication frameworks:
STIR/SHAKEN Framework:
Secure Telephone Identity Revisited (STIR) and Signature-based buy telemarketing data Handling of Asserted information using toKENs (SHAKEN) are protocols designed to verify the legitimacy of caller ID information.
When a call is initiated, the originating carrier cryptographically signs the call details, confirming the phone number’s authenticity.
The terminating carrier verifies the signature before passing the call to the recipient, allowing the recipient’s device or network to display a “verified” caller ID or flag suspicious calls.
Implementing STIR/SHAKEN helps prevent unauthorized spoofing by ensuring only valid numbers owned or authorized by the caller can be displayed.
2. Strict Telephony Infrastructure Controls
Preventing spoofing begins with controlling the telephony environment itself:
Use of Verified Outbound Numbers:
Telemarketing systems restrict outbound calls to only pre-approved, registered phone numbers assigned to the company.
This eliminates arbitrary caller ID manipulation within the dialing software or PBX systems.
Secure VoIP Gateways:
VoIP systems often enable caller ID manipulation. Using secure, authenticated gateways that enforce caller ID policies reduces spoofing risks.
Access Controls:
Only authorized personnel or systems have permission to configure outbound caller IDs or telephony infrastructure, reducing insider spoofing risk.
1. Implementation of Caller ID Authentication Protocols
A primary defense against spoofing is adopting industry-standard caller ID authentication frameworks:
STIR/SHAKEN Framework:
Secure Telephone Identity Revisited (STIR) and Signature-based buy telemarketing data Handling of Asserted information using toKENs (SHAKEN) are protocols designed to verify the legitimacy of caller ID information.
When a call is initiated, the originating carrier cryptographically signs the call details, confirming the phone number’s authenticity.
The terminating carrier verifies the signature before passing the call to the recipient, allowing the recipient’s device or network to display a “verified” caller ID or flag suspicious calls.
Implementing STIR/SHAKEN helps prevent unauthorized spoofing by ensuring only valid numbers owned or authorized by the caller can be displayed.
2. Strict Telephony Infrastructure Controls
Preventing spoofing begins with controlling the telephony environment itself:
Use of Verified Outbound Numbers:
Telemarketing systems restrict outbound calls to only pre-approved, registered phone numbers assigned to the company.
This eliminates arbitrary caller ID manipulation within the dialing software or PBX systems.
Secure VoIP Gateways:
VoIP systems often enable caller ID manipulation. Using secure, authenticated gateways that enforce caller ID policies reduces spoofing risks.
Access Controls:
Only authorized personnel or systems have permission to configure outbound caller IDs or telephony infrastructure, reducing insider spoofing risk.