NRF (Network Repository Function)

The Network Repository Function is the 5G core service registry: every Network Function registers its profile and capabilities with the NRF, and consumers query the NRF to discover producers. The NRF authenticates clients via OAuth2 access tokens and mutual TLS, and unauthorised access could let an attacker enumerate the entire 5G core or impersonate a service. Hardening the NRF and its NFprofile data is therefore central to Service-Based Architecture security.

Categories: Radio Access NetworkCore NetworkSignaling

NRF 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 NRF in the wider telecom-security picture, review 5G SA, AMF, IAP, MVNO, Service-Based Architecture (SBA) Security and TCAP.

Related terms

Equipment

5G SBA control (NRF, SCP, NSSF, BSF, NWDAF)

Articles in the P1 mobile network security guide

Related topic hubs

  • 5G Security 5G SBA, SEPP, SUCI, 5G-AKA, N32 and service-based interface security.
  • SEPP Security N32-c/N32-f, PRINS, JWE and OAuth 2.0 at the 5G roaming edge.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.