CVE-2021-0474
📋 TL;DR
This critical vulnerability in Android's Bluetooth AVRCP protocol allows remote attackers to execute arbitrary code without user interaction by sending specially crafted packets. It affects Android devices running versions 8.1 through 11, potentially compromising device security and user data.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
Android by Google
Android by Google
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, data theft, persistent backdoor installation, and lateral movement to other devices.
Likely Case
Device compromise allowing data exfiltration, surveillance capabilities, and installation of additional malware payloads.
If Mitigated
Limited impact if Bluetooth is disabled or devices are isolated from untrusted networks, though risk remains if Bluetooth is enabled.
🎯 Exploit Status
Exploitation requires Bluetooth proximity and knowledge of the vulnerability, but no authentication or user interaction.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin May 2021 patches
Vendor Advisory: https://source.android.com/security/bulletin/2021-05-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > Advanced > System update. 2. Install the May 2021 security patch or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable Bluetooth
androidTurn off Bluetooth to prevent remote exploitation via this vector
adb shell settings put global bluetooth_on 0
Settings > Connected devices > Connection preferences > Bluetooth > Toggle off
Restrict Bluetooth Visibility
androidSet Bluetooth to non-discoverable mode to reduce attack surface
Settings > Connected devices > Connection preferences > Bluetooth > Device name > Turn off 'Make device discoverable'
🧯 If You Can't Patch
- Disable Bluetooth completely when not in use
- Implement network segmentation to isolate vulnerable devices from critical systems
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If version is 8.1, 9, 10, or 11 and security patch level is before May 2021, device is vulnerable.Check Version:
adb shell getprop ro.build.version.release && adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level in Settings > About phone > Android security patch level shows 'May 5, 2021' or later.📡 Detection & Monitoring
Log Indicators:
- AVRCP protocol errors in Bluetooth logs
- Unexpected Bluetooth service crashes
- Suspicious Bluetooth pairing attempts from unknown devices
Network Indicators:
- Unusual Bluetooth traffic patterns
- AVRCP protocol anomalies in Bluetooth packet captures
SIEM Query:
source="android_logs" AND ("avrc" OR "AVRCP") AND ("overflow" OR "crash" OR "exception")