CVE-2021-0879
📋 TL;DR
This CVE describes an integer overflow vulnerability in the PowerVR kernel driver for Android devices. It allows local attackers to gain escalated privileges without user interaction by exploiting out-of-bounds heap access. This affects Android devices using PowerVR graphics hardware.
💻 Affected Systems
- Android devices with PowerVR graphics hardware
📦 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 bypass app sandboxing, access sensitive data from other apps, and install malicious apps with elevated permissions.
If Mitigated
Limited impact if devices are patched, have SELinux enforcing mode, and app sandboxing prevents initial access.
🎯 Exploit Status
Requires local access and knowledge of kernel memory layout. No public exploit code identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin April 2023 patches
Vendor Advisory: https://source.android.com/security/bulletin/2023-04-01
Restart Required: Yes
Instructions:
1. Check for Android security updates in device settings. 2. Apply April 2023 or later security patches. 3. Reboot device after update. 4. Verify patch installation through security patch level.
🔧 Temporary Workarounds
Disable vulnerable driver module
linuxPrevent loading of the vulnerable PowerVR kernel driver if not essential
echo 'blacklist pvrsrvkm' >> /etc/modprobe.d/blacklist.conf
rmmod pvrsrvkm
🧯 If You Can't Patch
- Restrict physical access to devices and implement strict app installation policies
- Use mobile device management (MDM) to enforce security controls and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android version. If before April 2023, device may be vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level shows '2023-04-05' or later in Android settings.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Unexpected privilege escalation attempts in audit logs
- SELinux denials related to PowerVR driver
Network Indicators:
- None - this is a local exploit
SIEM Query:
source="android_kernel" AND ("pvrsrv" OR "PowerVR") AND ("panic" OR "oops" OR "segfault")