Android FROST Attack: Security Fixes

TL;DR

The FROST attack exploits a weakness in Android’s encryption. This guide shows you how to check if your device is vulnerable and steps to mitigate the risk, including updating your software and using strong screen locks.

Understanding the FROST Attack

FROST (File-system Reversible Overlay System Technique) allows attackers with physical access to a locked Android device to decrypt data by exploiting weaknesses in how full disk encryption is implemented. Specifically, it targets devices using older versions of Android and those with weaker screen lock security.

Checking Your Device’s Vulnerability

1. Android Version: The attack primarily affects Android 7.0 (Nougat) and earlier. Newer versions have addressed many of the vulnerabilities, but it’s still important to check for updates.
   • Go to Settings > About phone > Software information.
   • Note your Android version.
2. Patch Level: Even on newer Android versions, security patches are crucial. Check the Security Patch Date.
   • In Settings > About phone > Software information, look for Security patch level.
   • A recent patch date (within the last few months) indicates your device is likely protected against known FROST vulnerabilities.

Mitigation Steps

1. Update Your Android OS: This is the most important step.
   • Go to Settings > System > System update (the exact path may vary slightly depending on your device manufacturer).
   • Check for and install any available updates. Repeat until no further updates are found.
2. Use a Strong Screen Lock: A strong screen lock makes it significantly harder for attackers to exploit the FROST vulnerability.
   • PIN: Use a PIN with at least 6 digits. Avoid easily guessable numbers like birthdates or sequences (1234, 5678).
   • Password: Use a strong password that is long and complex, containing a mix of uppercase and lowercase letters, numbers, and symbols.
   • Pattern: Avoid simple patterns. Use a pattern with at least 9 dots and avoid starting from the corners or edges.
   • Biometrics (Fingerprint/Face Unlock): While convenient, biometrics should be used *in addition to* a strong PIN or password, not as a replacement. If an attacker gains physical access, they may be able to bypass biometrics.
3. Enable Full Disk Encryption: Most modern Android devices have full disk encryption enabled by default, but it’s worth verifying.
   • Go to Settings > Security > Encryption (the exact path may vary).
   • Confirm that the device is encrypted. If not, follow the on-screen instructions to enable it. Note: This process can take a significant amount of time and will erase all data on your device, so back up everything first!
4. Be Aware of Physical Access: The FROST attack requires physical access to your unlocked device.
   • Protect your phone from theft or unauthorized access.
   • Never leave your phone unattended in public places.

Advanced Users (ADB Debugging)

If you have enabled ADB debugging, disable it unless actively using it for development purposes. ADB debugging can provide attackers with additional access to your device.

adb devices

This command lists connected devices. If a device is listed and you haven’t intentionally connected it, investigate immediately.