Gsma Fs.38 Link

Sniffing or spoofing unencrypted SIP signaling headers to harvest user metadata or intercept communication.

To address these vulnerabilities, the GSMA Fraud and Security Group (FASG) released , a Permanent Reference Document (PRD) titled "SIP Network Security." This document serves as a critical guide for Mobile Network Operators (MNOs) to defend against SIP-based attacks and ensure the integrity of converged networks. Why SIP Security Needs a Dedicated Standard

GSMA FS.38: A Definitive Guide to Securing SIP Network Infrastructure

The GSMA FS.38 is more than just a document; it is a vital tool that represents a new, more mature era of telecom security. By moving away from outdated models of implicit trust and sole reliance on firewalls, and embracing a defense-in-depth approach, the standard provides a comprehensive and actionable guide for network operators, vendors, and security professionals.

To build this layered defence, FS.38 details several key countermeasures, including but not limited to: gsma fs.38

The document moves beyond basic signaling security to cover a broader "attack surface," including: Holistic Network Coverage

"message_id": "fs38-20260410-0001", "timestamp_utc": "2026-04-10T12:34:56Z", "schema_version": "1.0", "sender_id": "operator-a", "event": "event_type": "SIM_SWAP", "msisdn": "+441234567890", "imsi": "234150123456789", "confidence_score": 88, "evidence": "detection_method": "OMA-SDM-signals", "log_refs": ["log-789", "cdr-4521"] , "recommended_action": "action_code": "TEMP_BLOCK", "suggested_ttl_seconds": 3600

GSMA FS.38 provides a comprehensive framework for 5G network slicing, covering several key areas:

As 5G networks continue to expand and rely more heavily on virtualized, cloud-native architectures, the importance of robust SIP security cannot be overstated. GSMA FS.38 provides the industry-vetted roadmap necessary to protect the privacy of billions of users and the stability of the global mobile ecosystem. Sniffing or spoofing unencrypted SIP signaling headers to

SIP is the "waiter" of the telecommunications world. When you place a VoLTE call, SIP is the protocol that takes your order, finds the person you're calling, and sets up the "table" (the connection) so you can talk.

| GSMA PRD | Title / Focus Area | What It Covers | | :--- | :--- | :--- | | | SS7 and SIGTRAN Network Security | Threat analysis, attack methods, and countermeasures for SS7 signaling | | FS.19 | Diameter Interconnect Security | Potential diameter-based attacks and mitigation strategies | | FS.20 | GPRS Tunnelling Protocol (GTP) Security | Security analysis for the GTP control plane | | FS.22 | VoLTE Security | Security analysis and recommendations specifically for VoLTE | | FS.36 | 5G Interconnect Security | Security considerations for 5G network interconnections | | FS.37 | GTP-U Security | Security recommendations for the GTP user plane | | FS.38 | SIP Network Security | Comprehensive guide to SIP-based attacks and countermeasures | | FS.39 | 5G Fraud Risks Guide | Describes potential attacks against 5G networks and their services |

: While some GSMA documents are public, FS.38 is typically a Members Only resource. Key Security Domains Covered

Recommends the deployment of Access Session Border Controllers (A-SBC) as a front-line defense against malicious traffic. By moving away from outdated models of implicit

FS.38 was developed to fill a void where no single, end-to-end document existed that addressed real-world SIP attacks and their countermeasures. As Tony Friar, the lead author of FS.38, notes, the intent is to shift the industry's thinking from a single line of defence to a comprehensive, integrated security posture for the protocol that powers modern voice and video communications.

: Security profiles for both SIM-enabled customer equipment (smartphones, IoT devices) and non-SIM endpoints (such as hosted corporate voice solutions).

Developed by the GSMA Fraud and Security Group (FASG) , FS.38 directly addresses the industry-wide shift from legacy SS7 and Diameter-based networks toward all-IP architectures like Voice over LTE (VoLTE), Voice over Wi-Fi (VoWiFi), and 5G Standalone (SA) core networks. The Shift to SIP and Rising Network Vulnerabilities

As the industry moves toward 5G, the importance of SIP security continues to grow. FS.38 is part of a broader suite of GSMA security documents—such as and FS.40 (5G Security) —that collectively ensure a resilient and trusted global mobile ecosystem. 38 integrates with 5G security frameworks ? Cybersecurity document library - GSMA Security

GSMA FS.38 represents a significant step forward in the quest for secure mobile authentication. By providing a standardized, robust framework for authentication, FS.38 has the potential to revolutionize the way we interact with mobile devices and sensitive services. As the mobile ecosystem continues to evolve, the importance of FS.38 will only grow, driving innovation, trust, and security in the digital age.