How to protect mobile devices from an IMSI catcher?

Protecting mobile devices from an IMSI catcher (known as Stingrays or cell site simulators) can be challenging. These surveillance tools are capable of intercepting and tracking mobile communications. You can take steps to increase your privacy and decrease the risk of IMSI catching:

1. Encrypt Your Communication: Enable encryption in your mobile device’s built-in encryption feature or via apps like Signal for end-to-end encrypted messaging and calling.
2. Avoid Public Wi-Fi Networks: An IMSI catcher exploits vulnerabilities found in public Wi-Fi to intercept communications. Be careful when connecting to a public Wi-Fi network you are unsure of. IMSI catchers can use them to listen in on your conversations.
3. Use a Virtual Private Network: When connecting to public WiFI networks or other untrusted networks, use a VPN to encrypt all your Internet traffic. This makes it difficult for IMSI catchers to intercept information.
4. Update your software regularly: Upgrade your mobile’s operating system, applications, and security patches regularly to protect against known vulnerabilities IMSI snatchers could exploit. This can help to protect against IMSI catcher attempts.
5. Disable Automatic Connections: By turning off automatic WiFi and Bluetooth connections, you can reduce the risk of accidentally connecting to fraudulent networks set up by an IMSI catcher.
6. Keep an eye out for abnormal network behaviors: Look for suspicious behavior in the network, such as sudden changes in signal strength and unexpected battery drain. These could be signs of an IMSI catcher nearby that needs to be tracked down and removed.
7. Strong Passwords and biometrics: Protect your device using solid passwords, pins, or biometric authentication to block unauthorized entry.
8. Switch off Cellular Data: When necessary, switch off cellular data to protect yourself from potential tracking.
9. Apps to detect IMSI catchers: Some third-party applications, such as AIMSICD or SnoopSnitch, claim to detect IMSI catchers. Their effectiveness may vary depending on the availability of devices and regions.
10. Physical Security: Be cautious of unfamiliar or suspicious devices near your phone. An IMSI catcher needs to be close for them to work.
11. Switch Off IMSI Transmission: Certain mobile phones allow you to turn off IMSI transmissions, making it harder for an IMSI catcher to target your device.
12. Consider Using a Faraday Sleeve or Bag: Incorporate a Faraday bag into your setup for complete isolation. This will block all radio waves.

These steps can reduce the risk of IMSI catcher exploitation but don’t guarantee complete protection. IMSI catcher software can be highly sophisticated. There’s always the possibility of new vulnerabilities being exploited. If you think your communications may be targeted, you can seek expert guidance or use advanced security measures.

I recommend visiting NIST and Zimperium’s Mobile Security Glossary to learn more about mobile security.