CVE-2021-1036
📋 TL;DR
CVE-2021-1036 is a tapjacking vulnerability in Android's LocationSettingsActivity that allows malicious apps to overlay deceptive UI elements on legitimate system dialogs. This could trick users into granting permissions or performing actions they didn't intend, potentially leading to privilege escalation. Affects Android 9 through 12 devices.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
Android by Google
Android by Google
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
An attacker could trick users into granting dangerous permissions (like accessibility services or device admin rights) leading to complete device compromise, data theft, or ransomware installation.
Likely Case
Malicious apps could trick users into granting location permissions or other sensitive permissions, enabling tracking, data collection, or further exploitation.
If Mitigated
With proper security controls and user awareness, the impact is limited to permission abuse rather than full device compromise.
🎯 Exploit Status
Exploitation requires user interaction (tapping on deceptive overlay) and a malicious app with SYSTEM_ALERT_WINDOW permission. No authentication bypass needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin January 2022 and later
Vendor Advisory: https://source.android.com/security/bulletin/aaos/2022-01-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install the January 2022 or later security patch. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable overlay permission for untrusted apps
androidPrevent apps from drawing over other apps by revoking SYSTEM_ALERT_WINDOW permission
adb shell appops set <package_name> SYSTEM_ALERT_WINDOW deny
Enable Google Play Protect
androidKeep Google Play Protect enabled to detect and block malicious apps using this technique
🧯 If You Can't Patch
- Educate users about tapjacking risks and to be cautious when granting permissions
- Implement mobile device management (MDM) policies to restrict app installations and overlay permissions
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If version is 9-12 without January 2022 security patch, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android version is patched: Settings > About phone > Android security patch level should show January 2022 or later.📡 Detection & Monitoring
Log Indicators:
- Multiple SYSTEM_ALERT_WINDOW permission requests from same app
- Unexpected permission grants in security logs
Network Indicators:
- No network indicators - local attack only
SIEM Query:
source="android_security" AND (event="permission_granted" AND permission="android.permission.SYSTEM_ALERT_WINDOW")