PSTN Security Testing Methodology

A comprehensive approach to assessing the security of Public Switched Telephone Network (PSTN) infrastructure

PSTN Security Testing Methodology

Structured PSTN Security Assessment

Follow a systematic approach to identify and assess vulnerabilities in PSTN infrastructure

Phase 1: Reconnaissance
Information gathering and network mapping
  • Identify PSTN infrastructure components
  • Map telephone number ranges and exchanges
  • Discover PBX systems and voicemail servers
  • Identify maintenance and testing interfaces
Duration: 1-2 days
Phase 2: Vulnerability Assessment
Systematic vulnerability identification
  • Scan for weak authentication mechanisms
  • Test signaling protocol implementations
  • Analyze switch configuration security
  • Assess physical security controls
Duration: 2-3 days
Phase 3: Exploitation
Controlled vulnerability exploitation
  • Test authentication bypass techniques
  • Attempt signaling manipulation attacks
  • Validate toll fraud vulnerabilities
  • Test call interception capabilities
Duration: 1-2 days
Phase 4: Post-Exploitation
Impact assessment and persistence testing
  • Assess data exfiltration capabilities
  • Test lateral movement possibilities
  • Evaluate service disruption impact
  • Document business impact scenarios
Duration: 1 day
Phase 5: Reporting
Comprehensive documentation and recommendations
  • Executive summary with risk ratings
  • Detailed technical findings
  • Remediation recommendations
  • Compliance gap analysis
Duration: 1-2 days
Phase 6: Remediation Support
Ongoing support and validation
  • Remediation guidance and support
  • Re-testing of fixed vulnerabilities
  • Security control validation
  • Final security assessment report
Duration: Ongoing

PSTN Security Testing Tools

Reconnaissance Tools

  • • ToneLoc - Automated phone number scanning
  • • THC-Scan - Telephone system enumeration
  • • WarVOX - VoIP war dialing framework
  • • PhoneInfoga - Phone number OSINT tool

Exploitation Tools

  • • Blue Box - MF signaling manipulation
  • • Red Box - Coin tone generation
  • • SIPVicious - SIP protocol testing suite
  • • Asterisk - Open source PBX platform

Key Testing Considerations

Legal and Compliance
  • • Obtain proper authorization before testing
  • • Comply with telecommunications regulations
  • • Document all testing activities
  • • Respect privacy and data protection laws
  • • Coordinate with network operations teams
Safety and Risk Management
  • • Avoid service disruption during testing
  • • Implement proper change control procedures
  • • Maintain emergency contact information
  • • Use isolated test environments when possible
  • • Monitor system performance during tests

Best Practices for PSTN Security Testing

Pre-Testing Preparation

  • ✓ Define clear testing objectives and scope
  • ✓ Obtain necessary approvals and authorizations
  • ✓ Prepare testing environment and tools
  • ✓ Establish communication protocols
  • ✓ Create detailed testing timeline

During Testing

  • ✓ Follow established testing procedures
  • ✓ Document all findings and observations
  • ✓ Maintain regular communication with stakeholders
  • ✓ Monitor system performance and stability
  • ✓ Escalate critical findings immediately