CVE-2023-20995
📋 TL;DR
This vulnerability allows bypassing fingerprint authentication on Android 13 devices due to a logic error in the CustomizedSensor.cpp file. An attacker with physical access could unlock the device without proper authentication, leading to local privilege escalation. Only Android 13 devices with fingerprint sensors are affected.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing unauthorized access to all user data, apps, and credentials stored on the device.
Likely Case
Unauthorized access to the device and sensitive user data when an attacker has physical access to the unlocked device.
If Mitigated
Limited impact if device has additional security layers like strong passwords, encryption, or remote wipe capabilities.
🎯 Exploit Status
Exploitation requires physical access to device but no user interaction. Logic error makes exploitation straightforward once identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Update March 2023 or later
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2023-03-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install March 2023 security update or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable Fingerprint Authentication
androidTemporarily disable fingerprint unlock and use alternative authentication methods
Settings > Security > Device unlock > Fingerprint > Remove fingerprints
Enable Additional Security Layers
androidConfigure device to require PIN/password after restart or at regular intervals
Settings > Security > Screen lock > Secure lock settings > Automatically lock (set to immediate)
🧯 If You Can't Patch
- Disable fingerprint authentication completely and use PIN/password only
- Enable device encryption and remote wipe capabilities
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If version is 13 and security patch level is before March 2023, device is vulnerable.Check Version:
Settings > About phone > Android versionVerify Fix Applied:
Verify Android version is 13 with security patch level March 2023 or later in Settings > About phone > Android version.📡 Detection & Monitoring
Log Indicators:
- Multiple failed fingerprint attempts followed by successful unlock without proper authentication
- Unusual unlock patterns or timing
Network Indicators:
- None - local exploitation only
SIEM Query:
Device logs showing fingerprint authentication bypass events or abnormal unlock sequences