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 AMPS, Artificial Traffic Inflation, Backhaul, BTS, CLI Spoofing and Flash Call Fraud — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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.