FS.11 (GSMA Vulnerability Disclosure Framework)

GSMA FS.11 is the Permanent Reference Document specifying the SS7 Interconnect Security Monitoring & Firewall Guidelines. It defines the well-known Category 1 (always blocked at interconnect), Category 2 (allowed only from the subscriber's current visited network), and Category 3 (rate-limited and behaviourally validated) classification for MAP operations, plus monitoring, logging, and incident-response expectations. FS.11 is the de facto global standard for SS7 firewall policy.

Categories: SignalingRoaming and InterconnectIdentity and Subscriber

FS.11 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 FS.11 in the wider telecom-security picture, review Roaming Security Assessment, Signaling Screening, TCAP Abuse, SS7 Message Categories, FS.07 and FS.19: 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.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • Roaming Security IPX/GRX interconnect risk, home-routed vs local-breakout, SEPP.

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.