TCAP Abuse

A class of SS7 attacks where an adversary with interconnect access uses crafted TCAP dialogues to invoke MAP, CAP, or INAP operations they should not be allowed to issue. Examples include sending unsolicited AnyTimeInterrogation to track a subscriber, ProvideRoamingNumber to intercept calls, or UpdateLocation to redirect SMS. Mitigation relies on SS7 firewalls applying GSMA FS.11 Category 1 and 2 filters, validating the originating Global Title, and correlating dialogues against the subscriber's known location.

Categories: SignalingRoaming and InterconnectIdentity and Subscriber

TCAP Abuse in context

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.

Roaming and interconnect are where two operators exchange signaling and user-plane traffic. Trust boundaries here are the primary attack surface for location tracking, SMS interception and fraud, which is why GSMA now mandates SEPP with PRINS on 5G interconnect.

To place TCAP Abuse in the wider telecom-security picture, review Behavioral Signaling Detection, FS.11, GRE, Roaming, Roaming Interconnect Security and Roaming Security Assessment — 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.