SMF (Session Management Function)

The Session Management Function is the 5G core network function responsible for the lifecycle of PDU sessions: IP address allocation, UPF selection and control via the N4/PFCP interface, QoS enforcement, charging triggers, and lawful interception coordination. The SMF interacts with the AMF, PCF, and UDM over service-based interfaces and is critical to user-plane security; misconfiguration or compromise can enable session hijacking, traffic redirection, or charging fraud.

Categories: Core NetworkThreats and AttacksFraud

SMF in context

The mobile core carries subscriber sessions, mobility and policy. 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.

Telecom threats range from opportunistic SMS phishing and SIM swap to nation-state grade location tracking. The common thread is that most attacks exploit the inherited trust model of legacy signaling protocols.

To place SMF in the wider telecom-security picture, review PGW, N4, N6, UDR, Backhaul and SCP Abuse: each entry cross-references back to this page so you can walk the topic in either direction.

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