Back to 2G Hacking
2G Hacking
Call Interception
Call interception attacks enable attackers to eavesdrop on voice communications by capturing and decrypting the audio stream between mobile devices and the network.
Critical Security Vulnerability
Voice calls in 2G networks use weak encryption (A5/1, A5/2) that can be broken in real-time. Attackers use IMSI catchers or fake base stations to position themselves as man-in-the-middle, capturing the encrypted audio stream and decrypting it using known vulnerabilities.
Attack Flow Diagram
Step-by-step visualization of the attack process
Impact
- Complete loss of voice communication privacy
- Exposure of confidential business discussions
- Personal privacy violations
- Intelligence gathering and espionage
- Blackmail and extortion opportunities
Attack Vectors
- IMSI catcher deployment for call capture
- A5/1 encryption breaking for decryption
- Fake BTS for man-in-the-middle positioning
- SS7 exploitation for call redirection
- Baseband processor exploitation
Attack Methodology
- 1Deploy IMSI catcher or fake BTS
- 2Force target device connection
- 3Capture encrypted voice stream
- 4Break A5/1 encryption using rainbow tables
- 5Decode and record voice communications
- 6Optionally relay to legitimate network for stealth
Mitigation Strategies
- Use encrypted VoIP applications (Signal, WhatsApp calls)
- Upgrade to 4G/5G with stronger encryption
- Disable 2G when not needed
- Use IMSI catcher detection apps
- Implement end-to-end encrypted voice solutions
- Monitor for forced network downgrades
Real-World Examples
- •Law enforcement wiretapping operations
- •Corporate espionage during negotiations
- •Government surveillance of journalists
- •Criminal interception for blackmail
- •Intelligence agency operations
Related Attacks
IMSI Catching
IMSI catchers are rogue base stations that trick mobile devices into connecting to them, allowing attackers to capture International Mobile Subscriber Identity (IMSI) numbers and intercept communications.
A5/1 Encryption Breaking
A5/1 is the encryption algorithm used in 2G GSM networks. Due to its weak 64-bit key and known vulnerabilities, it can be broken in real-time to decrypt voice calls and SMS messages.
Fake BTS Attacks
Fake Base Transceiver Station (BTS) attacks involve deploying rogue cell towers that impersonate legitimate network infrastructure to intercept communications and perform man-in-the-middle attacks.