CVE-2021-0429
📋 TL;DR
This CVE describes a use-after-free vulnerability in Android's ALooper component that could allow local privilege escalation without user interaction. An attacker could exploit memory corruption to gain elevated system privileges on affected devices. This affects Android versions 8.1 through 11.
💻 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
Complete device compromise allowing attacker to execute arbitrary code with system privileges, potentially installing persistent malware or accessing all user data.
Likely Case
Local privilege escalation allowing malware to gain higher permissions than originally granted, potentially bypassing sandbox protections.
If Mitigated
Limited impact if device is fully patched and has security features like SELinux properly configured.
🎯 Exploit Status
Exploitation requires local access to the device. No public exploit code is known, but the vulnerability is serious due to its privilege escalation nature.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin April 2021 patches
Vendor Advisory: https://source.android.com/security/bulletin/2021-04-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > Advanced > System update. 2. Install the April 2021 security patch or later. 3. Restart the device after installation.
🔧 Temporary Workarounds
No effective workarounds
allThis is a core framework vulnerability requiring patching at the OS level.
🧯 If You Can't Patch
- Restrict physical access to devices and monitor for suspicious app behavior
- Implement application allowlisting to prevent installation of potentially malicious apps
🔍 How to Verify
Check if Vulnerable:
Check Android version and security patch level in Settings > About phone > Android version. If security patch level is before April 2021 and Android version is 8.1-11, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level shows April 2021 or later in Settings > About phone > Android version.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- ALooper-related crash reports in logcat
- Unexpected privilege escalation attempts
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for: 'ALooper crash' OR 'use-after-free' OR 'privilege escalation' in Android device logs