MAP (Mobile Application Part)

The Mobile Application Part is the SS7 application protocol used in 2G and 3G networks for subscriber-related signalling: location updates, roaming, SMS delivery, supplementary services, and authentication vector retrieval from the HLR. MAP messages carry IMSIs, MSISDNs, and routing data in cleartext and assume the underlying SS7 network is trusted. As a result, MAP is the protocol abused by most well-known SS7 attacks (location tracking via SRI-SM, call and SMS interception via UpdateLocation), and filtering MAP operation codes is the central job of an SS7 firewall.

Categories: Core NetworkSignalingRoaming and Interconnect

MAP in context

The mobile core is where subscriber sessions, mobility and policy live. 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. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

Signaling protocols carry the control-plane instructions that set up calls, register subscribers, hand over sessions 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 FS.11 / FS.19 / FS.20 as a top-tier telecom risk.

To place MAP in the wider telecom-security picture, review MAP Security, HLR, Pentest, GTP, SGSN and Signaling Penetration Testing.

Related terms

Related topic hubs

  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • 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.
  • Diameter Attacks S6a IDR/PUR/CLR abuse, subscriber tracking, LTE signaling attacks.

More from the TelcoSec Glossary

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