CVE-2023-21135
📋 TL;DR
This vulnerability in Android's notification access settings allows local privilege escalation without user interaction. An attacker could exploit improper input validation to bypass notification permission controls, potentially accessing sensitive data or functionality. It affects Android 11 through 13 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 gains elevated privileges to access protected notification content, potentially reading sensitive information from other apps or performing unauthorized actions.
Likely Case
Local attacker bypasses notification permission controls to read notification content from apps they shouldn't have access to.
If Mitigated
With proper patching, the vulnerability is eliminated; without patching, risk is limited to local attackers with physical or remote shell access.
🎯 Exploit Status
Exploitation requires local access to the device. No user interaction needed once access is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin June 2023 patches
Vendor Advisory: https://source.android.com/security/bulletin/2023-06-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install the June 2023 security patch or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable notification access for untrusted apps
androidReview and disable notification access permissions for apps that don't require it
Settings > Apps & notifications > Special app access > Notification access
🧯 If You Can't Patch
- Restrict physical access to devices and implement strong device management policies
- Monitor for unusual notification access permission changes or privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If version is 11, 12, 12L, or 13 without June 2023 security patch, device is vulnerable.Check Version:
Settings > About phone > Android version and Android security patch levelVerify Fix Applied:
Verify Android security patch level is June 2023 or later in Settings > About phone > Android security patch level.📡 Detection & Monitoring
Log Indicators:
- Unusual notification permission changes in system logs
- Unexpected onCreate calls to NotificationAccessSettings
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Look for system events related to notification permission changes or privilege escalation attempts on Android devices