CVE-2021-0439
📋 TL;DR
This vulnerability allows local privilege escalation on Android 11 devices through an out-of-bounds write in the PowerManagerService component. Attackers can gain elevated system privileges without user interaction or additional permissions. Only Android 11 devices are affected.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to install persistent malware, access sensitive data, or disable security controls.
Likely Case
Local attackers gaining root access to install malicious apps, steal credentials, or modify system settings.
If Mitigated
Limited impact if devices are patched, isolated from untrusted users, or have additional security layers like verified boot.
🎯 Exploit Status
Requires local access but no user interaction. Exploit code has been published in security bulletins.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level 2021-04-01 or later
Vendor Advisory: https://source.android.com/security/bulletin/2021-04-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > Advanced > System update. 2. Install April 2021 or later security update. 3. Reboot device after installation.
🔧 Temporary Workarounds
Restrict local app installations
androidPrevent installation of untrusted applications that could exploit the vulnerability
adb shell settings put secure install_non_market_apps 0
🧯 If You Can't Patch
- Isolate vulnerable devices from untrusted users and networks
- Implement application allowlisting to prevent malicious app execution
🔍 How to Verify
Check if Vulnerable:
Check Settings > About phone > Android version (must be 11) and Security patch level (must be before 2021-04-01)Check Version:
adb shell getprop ro.build.version.release && adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Security patch level shows 2021-04-01 or later in Settings📡 Detection & Monitoring
Log Indicators:
- Unusual power management service crashes
- Unexpected privilege escalation attempts in system logs
Network Indicators:
- None (local exploit only)
SIEM Query:
source="android_system" AND (event="PowerManagerService_crash" OR event="privilege_escalation")