Telecommunications Security Testing Methodology

Professional approach to testing telecommunications infrastructure security

Legal Notice

All security testing must be conducted with explicit written authorization from the network operator. Unauthorized testing of telecommunications networks is illegal and may result in criminal prosecution.

Comprehensive

Covers all major telecommunications protocols and attack vectors

Structured

Step-by-step approach ensuring thorough coverage and documentation

Professional

Industry-standard methodology used by security professionals

Phase 1: Planning and Scoping

Objectives

Define clear objectives and boundaries for the security assessment

Key Activities:

• Obtain written authorization from network operator
• Define scope: protocols, systems, and testing boundaries
• Identify testing constraints and restrictions
• Establish communication channels with stakeholders
• Create testing schedule and timeline
• Set up secure testing environment

Required Documentation:

✓ Signed authorization letter
✓ Scope of work document
✓ Rules of engagement
✓ Emergency contact information
✓ Non-disclosure agreement

Phase 2: Reconnaissance

Network Information Gathering

• Identify Mobile Country Code (MCC) and Mobile Network Code (MNC)
• Determine signaling protocols in use (SS7, SIGTRAN, Diameter)
• Map network topology and interconnections
• Identify Global Title (GT) ranges
• Discover Point Codes and SCCP addresses
• Enumerate SIP/IMS infrastructure

Tools and Techniques

SS7SigPloit, SS7MAP
GTPWireshark, gtp-scan
SIPSIPVicious, sippts
OSINTPublic databases, operator info

Phase 3: Vulnerability Assessment

Protocol-Specific Testing

Systematic assessment of each protocol for known vulnerabilities

SS7SS7 Vulnerability Assessment

• Test for location tracking vulnerabilities (SendRoutingInfo)
• Check SMS interception capabilities (ForwardSM)
• Assess call interception risks (UpdateLocation)
• Test authentication bypass (InsertSubscriberData)
• Verify SCCP filtering effectiveness

GTPGTP Vulnerability Assessment

• Test for user impersonation (Create Session)
• Check DoS vulnerabilities (Echo Request flooding)
• Assess data interception risks (GTP-U tunneling)
• Test IMSI disclosure vulnerabilities
• Verify GTP firewall rules

SIPSIP/VoIP Vulnerability Assessment

• Test registration hijacking
• Check authentication bypass methods
• Assess call manipulation vulnerabilities
• Test for DoS attack vectors
• Verify TLS/SRTP implementation

Phase 4: Controlled Exploitation

Exploitation must be conducted in a controlled manner with continuous monitoring and immediate rollback capability. Never perform actions that could disrupt live services.

Safe Exploitation Guidelines

Pre-Exploitation Checklist:

✓ Verify authorization for exploitation phase
✓ Ensure monitoring systems are active
✓ Prepare rollback procedures
✓ Notify stakeholders of testing window
✓ Use isolated test environment when possible

Exploitation Approach:

• Start with least invasive tests
• Document every action and result
• Monitor for unintended side effects
• Limit scope to authorized targets only
• Stop immediately if issues arise

Phase 5: Documentation and Reporting

Comprehensive Reporting

Deliver actionable findings with clear remediation guidance

Report Structure:

Executive Summary - High-level overview for management
Methodology - Testing approach and scope
Findings - Detailed vulnerability descriptions with evidence
Risk Assessment - CVSS scores and business impact analysis
Recommendations - Prioritized remediation steps
Appendices - Technical details, tool outputs, references

For Each Finding Include:

• Vulnerability description and affected systems
• Proof of concept with screenshots/logs
• Risk rating (Critical/High/Medium/Low)
• Business impact assessment
• Detailed remediation steps
• References to standards (3GPP, GSMA, etc.)

Best Practices

Do's

✓ Always obtain written authorization
✓ Document everything thoroughly
✓ Use isolated test environments
✓ Follow responsible disclosure
✓ Maintain confidentiality
✓ Stay within defined scope

Don'ts

✗ Never test without authorization
✗ Don't disrupt live services
✗ Avoid testing on production systems
✗ Don't exceed authorized scope
✗ Never share findings publicly
✗ Don't use findings maliciously

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