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
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
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
Open source GSM baseband implementation for security research
- • Mobile-side GSM protocol stack
- • Layer 1-3 implementation
- • Supports various Calypso phones
- • Custom firmware development
GNU Radio blocks for GSM signal processing and analysis
- • GSM receiver implementation
- • Channel decoding
- • BCCH extraction
- • Traffic analysis tools
A5/1 encryption cracking tool using rainbow tables
- • Real-time A5/1 decryption
- • 2TB rainbow table support
- • GPU acceleration
- • Known plaintext attacks
Software-defined GSM access point for testing
- • Complete GSM network stack
- • SDR-based implementation
- • SIP/VoIP integration
- • Isolated test environments
Hardware tool for SIM card communication analysis
- • SIM-ME communication sniffing
- • APDU command analysis
- • Real-time monitoring
- • Protocol debugging
Modified phones for GSM security analysis
- • IMSI catcher detection
- • Encryption status display
- • Network analysis
- • Security alerts
2G Security Testing Best Practices
- Always obtain written authorization before testing
- Use isolated test environments when possible
- Respect privacy laws and regulations
- Document all testing activities thoroughly
- 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
- Be aware of RF exposure limits
- Avoid disrupting emergency services
- Use appropriate power levels for testing
- Coordinate with network operators
2G Pentesting Workflow
Radio Interface Testing
Focus on Um interface vulnerabilities, encryption weaknesses, and IMSI catching techniques using SDR equipment.
Core Network Testing
Target SS7 signaling vulnerabilities, HLR/VLR queries, and authentication bypass techniques.
Related Resources
Explore comprehensive attack vectors targeting 2G networks, from radio interface to core network.
Learn about specific exploits and tools used to compromise 2G network security.
Deep dive into SS7 protocol vulnerabilities and their exploitation in 2G networks.