Signaling Security Manual
Hardening SS7, Diameter, and GTP protocols against state-actor tracking, interconnection fraud, and DDoS.
Interconnection Protocols
Traditional telecom signaling was built on trust. Modern NIS2 compliance requires Zero-Trust at the STP/DRA/SEPP level.
Location tracking, SMS intercept, and fraud via remote MSC/VLR spoofing.
HSS tracking, DoS against mobility management nodes via S6a interface.
Traffic interception at the GRX/IPX level and TEID exhaustion attacks.
Mandatory Security Controls
Implementing the technical measures specified in GSMA FS.31 and ETSI standards.
Topology Hiding
Internal network identifiers (IMSI, MSISDN ranges, node IPs) must be masked at the boundary.
Message Screening
Filter incoming packets based on source, op-code, and consistency with traffic patterns.
Anti-Spoofing
Verify that the originating node is authorized to request information for the targeted subscriber.
Session Integrity
Ensure that signaling state matches the actual user attachment status.
Telecom Sector Deep Dive
Further guidelines and mitigations for interconnectivity, SIM systems, and legacy transitions.
5G Roaming & SEPP Peering Security
In 5G Standalone (SA) deployments, interconnect traffic goes over HTTP/2 via the N32 interface. Security Edge Protection Proxy (SEPP) must be configured on both sides to provide application-layer security, PRACK filtering, and TLS encryption. PRACK security ensures transit network intermediaries cannot modify critical parameters (e.g. routing information, IMSI).
Legacy Sunsetting Risks (2G/3G/4G)
As networks transition to 5G, operators must manage legacy protocols (SS7, Diameter). During the sunsetting phase, backward compatibility is often exploited by attackers downgrading users from 5G to 2G/3G. Firewalls must be tuned to reject unauthorized cross-protocol mapping requests (e.g. SS7 MAP requests targeting 5G-registered IMSIs).
SIM/eSIM Orchestration & RSP Security
Remote SIM Provisioning (RSP) platforms present critical threat surfaces. Unauthorized profile downloads or subscription changes lead to SIM swapping. Access control to RSP nodes (SM-DP+ and SM-SR) must use continuous Mutual Authentication, TLS 1.3, and strict SMS/OTA message signing.
Signaling Security Registry
Cross-reference table mapping protocols, transport ports, and risk classifications as defined by GSMA FS.19 and FS.31.
| Protocol | Default Ports | Category (GSMA) | Risk Profile | Mitigation Control |
|---|---|---|---|---|
| SS7 / MAP | SCTP 2905 (M3UA) | Category 3 | IMSI tracking, subscriber location spoofing, unauthorized profile mods. | SMS Home Routing, MAP op-code filtering |
| Diameter | SCTP/TCP 3868 | Category 2 | HSS/MME redirection, registration spoofing, Denial of Service (DoS). | DEA topology hiding, SCTP multi-homing filter |
| GTP-C | UDP 2123 | Category 3 | GGSN hijacking, session redirection, GTP-U tunnel sniffing. | GTP validation, TEID randomization |
| SIP | UDP/TCP 5060, TLS 5061 | Category 2 | VoLTE call interception, caller-ID spoofing, media gateway bypass. | SIP Digest, SBC edge filtering |
| HTTP/2 (N32) | TCP 443, 80 | Category 1 | JSON injection, 5G roaming interface flooding, PRACK interception. | SEPP validation, TLS 1.3 encryption |
Active Monitoring
Our platform includes real-time telemetry from signaling edge nodes to detect abnormal MAP/TCAP patterns using AI-driven anomaly detection.