2G Hacking

Downgrade Attacks

Downgrade attacks force mobile devices to connect to older, less secure network technologies (2G) where encryption is weaker and easier to break, enabling various attack vectors.

High Severity Attack

Attackers use jamming or fake base stations to block 3G/4G/5G signals, forcing devices to fall back to 2G networks. Once on 2G, devices are vulnerable to A5/1 encryption breaking, IMSI catching, and other legacy protocol attacks.

Attack Flow Diagram

Step-by-step visualization of the attack process

Impact

Exposure to weak 2G encryption
Vulnerability to IMSI catcher attacks
Increased susceptibility to interception
Bypass of modern security features
Denial of high-speed data services

Attack Vectors

Selective jamming of 3G/4G/5G frequencies
Fake BTS advertising only 2G support
Protocol manipulation to force downgrade
Exploiting automatic network selection
Combining with IMSI catcher for full attack chain

Attack Methodology

1Deploy jamming equipment for 3G/4G/5G bands
2Set up fake 2G BTS with strong signal
3Wait for devices to downgrade automatically
4Capture connections on 2G network
5Execute secondary attacks (IMSI catching, interception)
6Maintain downgrade to prevent re-upgrade

Mitigation Strategies

Disable 2G in device settings (LTE-only mode)
Use network selection to prefer 4G/5G
Monitor for unexpected network changes
Implement network-level downgrade detection
Use encrypted communication apps regardless of network
Deploy 2G sunset policies in networks

Real-World Examples

•IMSI catcher operations forcing 2G connection
•Surveillance operations at public events
•Border control and customs enforcement
•Corporate espionage at conferences
•Government surveillance programs

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.

References