CVE-2021-0929
📋 TL;DR
CVE-2021-0929 is a use-after-free vulnerability in Android's ION memory management subsystem that allows local attackers to corrupt kernel memory. This can lead to local privilege escalation without requiring user interaction or additional execution privileges. The vulnerability affects Android devices running vulnerable kernel versions.
💻 Affected Systems
- Android devices
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via kernel privilege escalation, allowing attackers to gain root access, install persistent malware, or bypass security controls.
Likely Case
Local privilege escalation allowing attackers to elevate from user-level to kernel-level privileges on compromised devices.
If Mitigated
Limited impact if SELinux policies, kernel hardening, and proper access controls prevent exploitation attempts.
🎯 Exploit Status
Exploitation requires local access to the device. The vulnerability has been publicly disclosed and proof-of-concept code exists in security research communities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android security patch level November 2021 or later
Vendor Advisory: https://source.android.com/security/bulletin/2021-11-01
Restart Required: Yes
Instructions:
1. Apply the November 2021 Android security patch from your device manufacturer. 2. Update the device through Settings > System > System update. 3. Reboot the device after the update completes.
🔧 Temporary Workarounds
Disable vulnerable ION functionality
linuxDisable or restrict ION DMA buffer operations if not required for device functionality
echo 0 > /sys/kernel/debug/ion/... (device-specific path)
🧯 If You Can't Patch
- Implement strict application sandboxing and SELinux policies to limit damage from potential exploitation
- Monitor for suspicious privilege escalation attempts and kernel memory corruption indicators
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level: Settings > About phone > Android security patch level. If before November 2021, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android security patch level shows November 2021 or later. Check kernel version for specific ION subsystem patches.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- ION subsystem error messages
- Unexpected privilege escalation attempts
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
source="android_kernel" AND ("ion_dma_buf_end_cpu_access" OR "use-after-free" OR "kernel panic")