CVE-2021-0505
📋 TL;DR
This vulnerability in Android 11's Settings app allows attackers to disable always-on VPN connections without proper permission checks. It enables local privilege escalation without requiring user interaction or additional execution privileges. Only Android 11 devices are affected.
💻 Affected Systems
- Android Settings application
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Attackers could disable VPN protection, intercept sensitive network traffic, bypass enterprise security policies, and potentially chain with other vulnerabilities for further system compromise.
Likely Case
Malicious apps could disable VPN protection to exfiltrate data, bypass network restrictions, or conduct man-in-the-middle attacks on device communications.
If Mitigated
With proper app sandboxing and network monitoring, impact is limited to potential data leakage from the compromised device only.
🎯 Exploit Status
Exploitation requires a malicious app to be installed on the target device. No user interaction needed once app is installed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level 2021-06-01 or later
Vendor Advisory: https://source.android.com/security/bulletin/2021-06-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > System update. 2. Install Android Security Patch Level 2021-06-01 or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Restrict app installations
androidPrevent installation of untrusted apps by enabling Google Play Protect and restricting installation from unknown sources
Settings > Security > Google Play Protect > Scan device for security threats
Settings > Security > Install unknown apps > Disable for all apps
Monitor VPN status
allImplement monitoring to detect when VPN connections are unexpectedly disabled
🧯 If You Can't Patch
- Implement mobile device management (MDM) solutions to detect and alert on VPN disconnections
- Use network-level controls to restrict traffic from devices not connected through approved VPN
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If it shows Android 11 and security patch level is earlier than 2021-06-01, device is vulnerable.Check Version:
adb shell getprop ro.build.version.release && adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android Security Patch Level is 2021-06-01 or later in Settings > About phone > Android security update.📡 Detection & Monitoring
Log Indicators:
- Unexpected VPN disconnection events
- Settings app activities modifying VPN configuration without user action
Network Indicators:
- Device traffic bypassing VPN tunnel
- Direct internet connections from devices that should be VPN-only
SIEM Query:
source="android_logs" AND (event="vpn_disconnected" OR event="vpn_configuration_changed") AND user="system_app"