Grey Route SMS

A grey-route SMS is an application-to-person (A2P) message delivered to a mobile subscriber via a path that bypasses the terminating operator's commercial A2P agreement — typically SIM-farm P2P injection, SS7 MAP MO-ForwardSM abuse, or misdeclared traffic — depriving the operator of revenue and undermining anti-spam controls.

Categories: SignalingIdentity and SubscriberFraud

Grey Route SMS in context

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.

Subscriber identifiers (IMSI, SUPI, MSISDN, IMEI) are the anchor for authentication, charging, lawful interception and fraud analytics. Any protocol or interface that leaks a permanent identifier is treated as a serious privacy defect, which is why 5G introduced SUCI concealment on the air interface.

To place Grey Route SMS in the wider telecom-security picture, review Bypass Fraud, MSC, GSMA T-ISAC, Interconnect Bypass Fraud, RCS and SIM Box.

Related terms

Related topic hubs

  • SMS Firewall SMS spam, phishing, A2P bypass and MAP-layer SMS filtering.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • SS7 Firewall GSMA FS.11 category 1/2/3 SS7 message screening at the STP edge.

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