CVE-2021-0707
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Android kernel's DMA buffer subsystem that allows local privilege escalation. An attacker with local access can exploit memory corruption to gain elevated privileges without user interaction. This affects Android devices running vulnerable kernel versions.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root privileges, allowing installation of persistent malware, data theft, and bypassing all security controls.
Likely Case
Local privilege escalation to root, enabling attackers to bypass app sandboxing, access sensitive data, and install malicious apps.
If Mitigated
Limited impact if devices are patched, have SELinux enforcing mode, and follow Android security best practices.
🎯 Exploit Status
Exploitation requires local access and kernel knowledge, but no authentication or user interaction is needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android security patch level 2022-04-01 or later
Vendor Advisory: https://source.android.com/security/bulletin/2022-04-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install the April 2022 security patch or later. 3. Reboot the device after installation.
🔧 Temporary Workarounds
No effective workarounds
allThis is a kernel-level vulnerability that requires patching. No configuration changes or workarounds can mitigate the vulnerability.
🧯 If You Can't Patch
- Restrict physical access to devices and implement strict app installation policies
- Monitor for suspicious privilege escalation attempts and unusual root access
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android security patch level. If date is before April 2022, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android security patch level shows April 2022 or later date in Settings > About phone > Android security patch level.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- SELinux denials for unexpected privilege escalation
- Unexpected root access in system logs
Network Indicators:
- No network indicators for this local vulnerability
SIEM Query:
source="android_system" AND (event_type="kernel_panic" OR message="use-after-free" OR message="dma_buf")