CVE-2023-21040
📋 TL;DR
This CVE describes a local privilege escalation vulnerability in Android's Bluetooth stack. An attacker can exploit a logic error in the bluetooth_ccc.cc file to perform out-of-bounds writes, potentially gaining elevated privileges without user interaction. This affects Android devices with vulnerable kernel versions.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise - attacker gains root/system-level access, can install persistent malware, access all user data, and control device functions.
Likely Case
Local privilege escalation allowing installation of malicious apps, data theft, or persistence mechanisms on compromised devices.
If Mitigated
Limited impact with proper security controls - SELinux policies, app sandboxing, and regular updates would contain the damage.
🎯 Exploit Status
Requires local access to device. No user interaction needed once exploit is executed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: March 2023 Android Security Patch or later
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2023-03-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > System update. 2. Install March 2023 or later security patch. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable Bluetooth
androidTemporarily disable Bluetooth to prevent exploitation through this vector
adb shell settings put global bluetooth_on 0
Settings > Connected devices > Connection preferences > Bluetooth > Turn off
🧯 If You Can't Patch
- Implement strict app installation policies to prevent malicious apps from gaining initial access
- Use Mobile Device Management (MDM) solutions to enforce security policies and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level: Settings > About phone > Android version > Build number. If before March 2023, likely vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level shows March 2023 or later in Settings > About phone📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Bluetooth service crashes
- SELinux denials related to Bluetooth
Network Indicators:
- Unusual Bluetooth pairing attempts
- Suspicious Bluetooth traffic patterns
SIEM Query:
source="android_logs" AND ("bluetooth_ccc" OR "kernel panic" OR "out of bounds")