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Vol. 1 · Ed. 2026
CyberGlossary
Entry № 1211

VoLTE Security

What is VoLTE Security?

VoLTE SecurityVoice-over-LTE security: the set of IMS authentication, signalling, and media protections that secure voice calls carried as SIP/RTP over 4G or 5G data bearers.


VoLTE (Voice over LTE) carries voice as SIP signalling and RTP media over a dedicated EPS bearer. Security is anchored in IMS-AKA (3GPP TS 33.203), where the UE uses the ISIM application on the USIM to mutually authenticate with the P-CSCF / S-CSCF. SIP signalling between the UE and P-CSCF is protected by IPsec ESP in transport mode with negotiated SA pairs, while media is protected hop-by-hop on the operator side. Critical hardening includes proper enforcement of integrity protection, validation of media gates by the P-CSCF, blocking unauthenticated SIP REGISTER spoofing, and DNS rebinding controls. Operator failures have enabled IMS-side IMSI exposure (CVE-2017-15303), free-data tunneling, and call-spoofing of mass-scale Robocalls.

Examples

  1. 01

    A VoLTE phone using IMS-AKA over an IPsec-protected SIP REGISTER toward the P-CSCF.

  2. 02

    An operator deploying a SIP signalling firewall to block spoofed P-Asserted-Identity from interconnect peers.

Frequently asked questions

What is VoLTE Security?

Voice-over-LTE security: the set of IMS authentication, signalling, and media protections that secure voice calls carried as SIP/RTP over 4G or 5G data bearers. It belongs to the Network Security category of cybersecurity.

What does VoLTE Security mean?

Voice-over-LTE security: the set of IMS authentication, signalling, and media protections that secure voice calls carried as SIP/RTP over 4G or 5G data bearers.

How does VoLTE Security work?

VoLTE (Voice over LTE) carries voice as SIP signalling and RTP media over a dedicated EPS bearer. Security is anchored in IMS-AKA (3GPP TS 33.203), where the UE uses the ISIM application on the USIM to mutually authenticate with the P-CSCF / S-CSCF. SIP signalling between the UE and P-CSCF is protected by IPsec ESP in transport mode with negotiated SA pairs, while media is protected hop-by-hop on the operator side. Critical hardening includes proper enforcement of integrity protection, validation of media gates by the P-CSCF, blocking unauthenticated SIP REGISTER spoofing, and DNS rebinding controls. Operator failures have enabled IMS-side IMSI exposure (CVE-2017-15303), free-data tunneling, and call-spoofing of mass-scale Robocalls.

How do you defend against VoLTE Security?

Defences for VoLTE Security typically combine technical controls and operational practices, as detailed in the full definition above.

What are other names for VoLTE Security?

Common alternative names include: Voice over LTE, IMS security.

Related terms