CVE-2021-0531
📋 TL;DR
This vulnerability in Android's memory management driver allows local attackers to escalate privileges without user interaction by exploiting a use-after-free condition. It affects Android devices with specific System-on-Chip (SoC) implementations. Successful exploitation could give attackers full system control.
💻 Affected Systems
- Android devices with specific SoC implementations
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise with root privileges, allowing installation of persistent malware, data theft, and bypassing all security controls.
Likely Case
Local privilege escalation enabling attackers to gain elevated permissions, potentially leading to data access, surveillance capabilities, or further system exploitation.
If Mitigated
Limited impact if devices are patched, isolated from untrusted users, or have additional security layers like SELinux enforcing strict policies.
🎯 Exploit Status
Exploitation requires local access but no user interaction. Use-after-free vulnerabilities typically require precise timing and memory manipulation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: June 2021 Android Security Bulletin patches
Vendor Advisory: https://source.android.com/security/bulletin/2021-06-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Apply June 2021 or later security patches. 3. Reboot device after update installation.
🔧 Temporary Workarounds
Restrict local access
allLimit physical and remote local access to devices through device management policies
Enable SELinux enforcing mode
linuxEnsure SELinux is in enforcing mode to limit privilege escalation impact
getenforce
setenforce 1
🧯 If You Can't Patch
- Isolate affected devices from untrusted users and networks
- Implement application allowlisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android version. If patch level is before June 2021, device may be vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level shows June 2021 or later in Settings > About phone > Android version.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Memory corruption errors in dmesg
- Unexpected privilege escalation attempts
Network Indicators:
- Unusual outbound connections from system processes
- Suspicious local network scanning
SIEM Query:
source="android_kernel" AND ("use-after-free" OR "memory corruption" OR "segmentation fault")