CVE-2023-21004
📋 TL;DR
This vulnerability allows local attackers to bypass permission checks in Android's Transcode Permission Controllers, potentially gaining elevated privileges without user interaction. It affects Android 13 devices, particularly those running vulnerable Pixel builds. The flaw enables privilege escalation from a local context.
💻 Affected Systems
- Android
- Google Pixel devices
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to execute arbitrary code with system-level privileges, access sensitive data, or install persistent malware.
Likely Case
Limited privilege escalation allowing access to protected system functions or data that should require explicit user permission.
If Mitigated
No impact if patched; otherwise, risk depends on other security controls like SELinux policies and app sandboxing.
🎯 Exploit Status
Requires local access to device; no user interaction needed but attacker needs some initial access to trigger the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level 2023-03-01 or later
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2023-03-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > System update. 2. Install Android Security Patch Level 2023-03-01 or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Restrict local app installations
androidPrevent installation of untrusted apps that could exploit this vulnerability
adb shell settings put secure install_non_market_apps 0
🧯 If You Can't Patch
- Implement strict app vetting policies to prevent malicious apps from being installed
- Use mobile device management (MDM) solutions to enforce security policies and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check Android Security Patch Level in Settings > About phone > Android version. If patch level is earlier than 2023-03-01, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android Security Patch Level shows 2023-03-01 or later in Settings > About phone > Android version.📡 Detection & Monitoring
Log Indicators:
- Unusual permission requests in system logs
- Suspicious activity in Transcode Permission Controllers
Network Indicators:
- None - this is a local privilege escalation
SIEM Query:
Look for events related to permission bypass or privilege escalation in Android system logs