CVE-2021-1039
📋 TL;DR
This vulnerability allows local attackers to perform a tapjacking/overlay attack on Android's notification access activity, potentially gaining elevated privileges without needing additional execution permissions. It affects Android devices running versions 9 through 12, requiring user interaction for successful exploitation.
💻 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 gain full control of the device by tricking users into granting notification access permissions to malicious apps, leading to complete compromise of user data and device functionality.
Likely Case
Malicious apps could gain unauthorized access to sensitive notifications and potentially escalate privileges to perform actions with elevated permissions.
If Mitigated
With proper security controls and user awareness, the risk is reduced as exploitation requires user interaction and can be prevented by careful permission management.
🎯 Exploit Status
Exploitation requires user interaction through tapjacking/overlay attacks. No public proof-of-concept has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin December 2021 patches
Vendor Advisory: https://source.android.com/security/bulletin/aaos/2021-12-01
Restart Required: Yes
Instructions:
1. Apply the December 2021 Android security patch. 2. Update affected Android devices through Settings > System > System update. 3. Ensure all devices receive the security patch level 2021-12-01 or later.
🔧 Temporary Workarounds
Disable notification access for untrusted apps
androidPrevent apps from accessing notifications by reviewing and disabling notification access permissions for untrusted applications.
Settings > Apps & notifications > Special app access > Notification access
Enable Google Play Protect
androidEnsure Google Play Protect is enabled to detect and prevent installation of potentially harmful applications.
Settings > Security > Google Play Protect
🧯 If You Can't Patch
- Implement mobile device management (MDM) policies to restrict installation of untrusted applications
- Educate users about the risks of tapjacking attacks and encourage careful review of permission requests
🔍 How to Verify
Check if Vulnerable:
Check Android version and security patch level: Settings > About phone > Android version and Security patch level. If running Android 9-12 with patch level before December 2021, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level is 2021-12-01 or later in Settings > About phone > Security patch level.📡 Detection & Monitoring
Log Indicators:
- Unusual notification access permission grants
- Multiple overlay permission requests from same app
Network Indicators:
- No network indicators as this is a local vulnerability
SIEM Query:
No specific SIEM query as this is client-side vulnerability requiring device-level monitoring