SUPI Catcher

In telecommunications, a SUPI Catcher is the 5G analog of an IMSI catcher: a rogue base station or man-in-the-middle device that attempts to capture or de-conceal the long-term subscriber identifier. SUPI concealment via SUCI mitigates passive capture, but active downgrade or implementation flaws can still expose the SUPI.

Categories: Radio Access NetworkSignalingIdentity and Subscriber

SUPI Catcher in context

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

Signaling protocols carry the control-plane messages that set up calls, register subscribers and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA as top-tier telecom risk.

To place SUPI Catcher in the wider telecom-security picture, review BTS Impersonation (Fake BTS), Rogue Base Station (Fake BTS), SUPI Concealment, TMSI, GTP-C Spoofing and Cleartext (Plain Text): each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

Related topic hubs

  • 5G Security 5G SBA, SEPP, SUCI, 5G-AKA, N32 and service-based interface security.
  • IMSI Catcher Rogue base stations, IMSI capture and detection.
  • 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.