BTS Impersonation (Fake BTS)

BTS impersonation is the attack in which an adversary deploys equipment that impersonates a legitimate base transceiver station, exploiting the lack of mutual authentication in 2G GSM and weaknesses in early 3G to capture IMSIs, downgrade encryption, or relay calls and SMS. It is the implementation pattern behind IMSI catchers and is mitigated by 4G/5G mutual authentication, the use of integrity-protected paging in 5G, and operator policies that disable 2G fallback in high-risk areas.

Categories: Radio Access NetworkSignalingIdentity and Subscriber

BTS Impersonation (Fake BTS) 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 BTS Impersonation (Fake BTS) in the wider telecom-security picture, review Cleartext (Plain Text), E911, OFCS, Rogue Base Station (Fake BTS), SMS Pumping and UMTS — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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