CVE-2021-0612
📋 TL;DR
CVE-2021-0612 is a use-after-free vulnerability in MediaTek's m4u (Memory Management Unit) driver that could allow local attackers to escalate privileges. Exploitation requires System execution privileges but no user interaction, potentially leading to kernel memory corruption. This affects devices using vulnerable MediaTek chipsets.
💻 Affected Systems
- MediaTek chipsets with m4u driver
📦 What is this software?
Android by Google
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with kernel-level code execution, allowing attackers to bypass all security controls, install persistent malware, or access sensitive data.
Likely Case
Local privilege escalation from a compromised app or user to root/system privileges, enabling further attacks on the device.
If Mitigated
Limited impact if proper kernel hardening, SELinux/AppArmor policies, and privilege separation are implemented to contain the exploit.
🎯 Exploit Status
Requires System execution privileges initially. No public exploit code identified, but use-after-free vulnerabilities in kernel drivers are often exploitable.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patch ID: ALPS05403499
Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/September-2021
Restart Required: Yes
Instructions:
1. Contact device manufacturer for firmware updates. 2. Apply MediaTek patch ALPS05403499. 3. Update Android security patches. 4. Reboot device after patching.
🔧 Temporary Workarounds
Restrict system privileges
androidLimit applications with System execution privileges using SELinux/AppArmor policies
# Review and tighten SELinux policies
# Restrict system service permissions
🧯 If You Can't Patch
- Implement strict application sandboxing and privilege separation
- Monitor for unusual privilege escalation attempts and kernel crashes
🔍 How to Verify
Check if Vulnerable:
Check device chipset and firmware version against MediaTek's advisory. Review kernel logs for m4u driver crashes.Check Version:
# Check Android security patch level: Settings > About phone > Android security patch levelVerify Fix Applied:
Verify patch ALPS05403499 is applied in firmware version. Check that September 2021 or later security patches are installed.📡 Detection & Monitoring
Log Indicators:
- Kernel panic or crashes related to m4u driver
- Unexpected privilege escalation attempts
Network Indicators:
- None - local exploitation only
SIEM Query:
source="kernel" AND ("m4u" OR "use-after-free" OR "kernel panic")