CVE-2021-0927
📋 TL;DR
This vulnerability allows local attackers to bypass permission checks in Android's TV input manager service, potentially gaining elevated privileges without user interaction. It affects Android devices running versions 8.1 through 12, requiring no additional execution privileges for exploitation.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
Android by Google
Android by Google
Android by Google
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
An attacker could gain full system-level control over the device, compromising all user data and system integrity.
Likely Case
Local privilege escalation allowing unauthorized access to sensitive TV-related functions or system resources.
If Mitigated
Limited impact if devices are patched or isolated, with minimal exposure to untrusted apps.
🎯 Exploit Status
Exploitation requires local access and knowledge of the vulnerability, but no user interaction is needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin November 2021 patches
Vendor Advisory: https://source.android.com/security/bulletin/2021-11-01
Restart Required: Yes
Instructions:
1. Check for system updates in device settings. 2. Apply the November 2021 Android security patch. 3. Reboot the device after installation.
🔧 Temporary Workarounds
Restrict app installations
androidLimit installation of untrusted apps to reduce attack surface from malicious local applications.
Enable 'Install unknown apps' restrictions in Android settings for all apps.
🧯 If You Can't Patch
- Isolate affected devices from sensitive networks to limit potential damage from compromised systems.
- Monitor for unusual app behavior or privilege escalation attempts using security tools.
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version; if it's 8.1 to 12 and not patched with November 2021 updates, it's vulnerable.Check Version:
adb shell getprop ro.build.version.releaseVerify Fix Applied:
Verify the Android security patch level is November 2021 or later in Settings > About phone > Android security patch level.📡 Detection & Monitoring
Log Indicators:
- Unusual permission requests or TV input service access in system logs, such as logcat entries related to TvInputManagerService.
Network Indicators:
- None, as this is a local exploit with no network activity required.
SIEM Query:
Search for log events containing 'TvInputManagerService' or 'requestChannelBrowsable' with suspicious context on Android devices.