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 FS.11, Signaling Screening, SS7, SS7 Message Categories, Behavioral Signaling Detection and Roaming: each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

Related topic hubs

  • SS7 Firewall GSMA FS.11 category 1/2/3 SS7 message screening at the STP edge.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • Diameter Security 4G/LTE Diameter threats across IPX/roaming and DEA defenses.

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