User Plane Security

User plane security covers the controls that protect subscriber data traffic as it traverses the mobile network: ciphering and integrity protection on the radio interface (NEA/NIA in 5G), GTP firewalling on inter-PLMN links, IPsec on backhaul and N3, and access controls at the UPF/PGW. 5G adds optional integrity protection of the user plane all the way to the gNB.

Categories: Radio Access NetworkCore NetworkSignaling

User Plane Security in context

The radio access network is the layer where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations, downgrade attacks and jamming, and defenses hinge on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

The mobile core is where subscriber sessions, mobility and policy live. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

To place User Plane Security in the wider telecom-security picture, review Base Station (BS), IAP, IPsec, Service-Based Architecture (SBA) Security, Mobile Network and IMS-AKA.

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