2G Security Methodology
2G/GSM Pentesting Methodology
Master the systematic approach to 2G/GSM security testing. From radio interface attacks to core network exploitation, learn how to identify and exploit vulnerabilities in legacy mobile networks.
2G Security Testing Framework
Legal Notice
This methodology is for authorized security testing only. Always obtain proper authorization before conducting any security assessments on telecommunications infrastructure.
2G/GSM networks, despite being legacy technology, remain widely deployed globally and present unique security challenges. This methodology provides a structured approach to identifying and exploiting vulnerabilities in GSM networks, from the radio interface to the core network components.
Our approach covers the entire attack surface of 2G networks, including encryption weaknesses, authentication vulnerabilities, signaling protocol exploits, and implementation flaws that have persisted for decades.
2G Pentesting Phases
Phase 1: Planning and Preparation
Establish objectives, scope, and legal framework for 2G security testing
Key Activities:
- Define testing scope (BTS, BSC, MSC, HLR, VLR, AuC)
- Obtain legal authorization and NDA agreements
- Identify target frequency bands (GSM 900/1800/1900)
- Prepare testing equipment (SDR, IMSI catchers, protocol analyzers)
- Set up isolated testing environment
Required Equipment:
Hardware
- • USRP/HackRF/BladeRF SDR
- • GSM test phones
- • Faraday cage/RF shielding
- • Spectrum analyzer
- • Protocol analyzers
Software
- • OsmocomBB
- • OpenBTS/YateBTS
- • gr-gsm
- • Wireshark with GSM plugins
- • Kraken A5/1 cracker
Essential 2G Testing Tools
OsmocomBB
- • Mobile-side GSM protocol stack
- • Layer 1-3 implementation
- • Supports various Calypso phones
- • Custom firmware development
gr-gsm
- • GSM receiver implementation
- • Channel decoding
- • BCCH extraction
- • Traffic analysis tools
Kraken
- • Real-time A5/1 decryption
- • 2TB rainbow table support
- • GPU acceleration
- • Known plaintext attacks
OpenBTS
- • Complete GSM network stack
- • SDR-based implementation
- • SIP/VoIP integration
- • Isolated test environments
SIMtrace
- • SIM-ME communication sniffing
- • APDU command analysis
- • Real-time monitoring
- • Protocol debugging
GSMK CryptoPhone
- • IMSI catcher detection
- • Encryption status display
- • Network analysis
- • Security alerts
2G Security Testing Best Practices
Legal and Ethical Considerations
- Always obtain written authorization before testing
- Use isolated test environments when possible
- Respect privacy laws and regulations
- Document all testing activities thoroughly
Technical Best Practices
- Start with passive reconnaissance before active testing
- Use RF shielding to prevent interference
- Verify findings with multiple tools and methods
- Keep testing equipment and software updated
Safety Considerations
- Be aware of RF exposure limits
- Avoid disrupting emergency services
- Use appropriate power levels for testing
- Coordinate with network operators
2G Pentesting Workflow
