CVE-2020-27052
📋 TL;DR
CVE-2020-27052 is an Android vulnerability that allows any app to bypass permissions and start in Lock Task Mode, which restricts users to a single app. This enables local privilege escalation without requiring user interaction or additional permissions. Only Android 11 devices are affected.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
An attacker could lock the device to a malicious app, preventing users from accessing other apps or settings, potentially leading to data theft or ransomware scenarios.
Likely Case
Malicious apps could hijack device functionality, restrict user access to legitimate apps, and maintain persistence on compromised devices.
If Mitigated
With proper app vetting and security controls, exploitation would be limited to already-compromised devices with malicious apps installed.
🎯 Exploit Status
Exploitation requires a malicious app to be installed on the device. No user interaction needed once app is installed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level 2020-12-01 or later
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2020-12-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > Advanced > System update. 2. Install the December 2020 security patch or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable Unknown Sources
androidPrevent installation of apps from unknown sources to reduce risk of malicious app installation
Settings > Security > Install unknown apps > Disable for all apps
Use Enterprise Management
allDeploy Mobile Device Management (MDM) to control app installation and Lock Task Mode settings
🧯 If You Can't Patch
- Implement strict app vetting policies to prevent installation of untrusted applications
- Use Android Enterprise or MDM solutions to restrict Lock Task Mode functionality
🔍 How to Verify
Check if Vulnerable:
Check Android version: Settings > About phone > Android version. If version is 11 and security patch level is before December 2020, 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 2020-12-01 or later in Settings > About phone > Android security patch level.📡 Detection & Monitoring
Log Indicators:
- Unexpected Lock Task Mode activations in system logs
- Apps requesting unusual permissions related to device administration
Network Indicators:
- Unusual network traffic from apps running in Lock Task Mode
SIEM Query:
source="android_system" AND "Lock Task Mode" AND action="start" AND NOT app_name IN ["approved_apps_list"]