CVE-2023-21147
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Android kernel's I2C device driver that allows local privilege escalation without user interaction. Attackers can exploit this logic error to gain elevated system privileges on affected Android devices. Only Android devices with specific kernel versions are impacted.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise allowing attackers to execute arbitrary code with kernel privileges, install persistent malware, access all user data, and bypass all security controls.
Likely Case
Local privilege escalation allowing malicious apps to break out of sandbox and gain system-level access to sensitive resources and other apps' data.
If Mitigated
Limited impact if devices are patched, have SELinux enforcing mode, and app sandboxing prevents initial access to the vulnerable component.
🎯 Exploit Status
Requires local access but no user interaction. Exploitation involves triggering the use-after-free condition to manipulate kernel memory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: June 2023 Android Security Bulletin patches
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2023-06-01
Restart Required: Yes
Instructions:
1. Apply June 2023 Android security patch via OTA update. 2. For Pixel devices, ensure build number includes June 2023 security patch level. 3. Reboot device after update installation.
🔧 Temporary Workarounds
Disable vulnerable I2C devices
linuxDisable I2C devices that use the vulnerable driver if not required for device functionality
echo 0 > /sys/bus/i2c/devices/[device]/enable
🧯 If You Can't Patch
- Restrict physical access to devices and implement strict app installation policies
- Enable SELinux enforcing mode and implement application sandboxing to limit exploit impact
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android version. If before June 2023, device is vulnerable.Check Version:
getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level shows 'June 5, 2023' or later in Settings > About phone > Android version.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- SELinux denials related to I2C device access
- Unexpected privilege escalation attempts
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
source="android_kernel" AND ("lwis_i2c" OR "use-after-free" OR "kernel panic")