Telecom Security Audit

A telecom security audit is a structured assessment of a mobile network operator's security posture across signalling, core, roaming and where applicable RAN, measured against external baselines rather than against an attacker. Where a penetration test answers "what can an attacker do right now?", an audit answers "does this network meet the controls that 3GPP, the GSMA and the relevant regulator say it should?". The two are complementary and most operators run both on different cadences.

Scope is anchored to the published baselines. GSMA FS.11 covers SS7 Category 1/2/3 screening and STP hardening; FS.19 covers Diameter screening and Diameter Edge Agent configuration; FS.20 covers GTP roaming; FS.21 covers SMS controls; FS.36 and related documents cover 5G interconnect and SEPP. 3GPP TS 33.117 defines the generic Security Assurance Specification (SCAS) requirements that every network function should meet, and TS 33.501 defines the 5G System security architecture. Where SIP/IMS, VoLTE or VoWiFi are in scope, the relevant 3GPP and GSMA documents are applied in the same way. On the regulator side, NIS2 in the EU and equivalent regimes elsewhere expect evidence that an operator has assessed and remediated against this control set.

A credible audit produces three artefacts: a per-control finding (compliant / partial / non-compliant with evidence), a per-finding remediation plan with effort and dependencies, and an executive summary mapped to business and regulatory impact. Because configuration drift is the norm rather than the exception on a live operator network, audits are normally run on a recurring cadence (annual baseline, ad-hoc after material network changes), and findings are tracked to closure rather than treated as one-off reports. For protocol-specific control detail see the SS7, Diameter, GTP and SMS firewall guides; for the 5G slice and SBA layer see 5G Security.