CVE-2023-21117
📋 TL;DR
This vulnerability allows isolated processes on Android 13 devices to register broadcast receivers without proper permissions, bypassing security restrictions. It enables local privilege escalation without requiring user interaction or additional execution privileges. Only Android 13 devices are affected.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
An attacker gains elevated privileges on the device, potentially accessing sensitive data, installing malware, or taking full control of the device.
Likely Case
Malicious apps could bypass security sandboxing to access protected system functions or data they shouldn't have access to.
If Mitigated
With proper app isolation and security controls, impact is limited to the specific vulnerable component, but privilege escalation remains possible.
🎯 Exploit Status
Requires local access and ability to run code on the device. No user interaction needed once code is executing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin May 2023 patches
Vendor Advisory: https://source.android.com/security/bulletin/2023-05-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install the May 2023 security patch or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable unknown sources
androidPrevent installation of apps from unknown sources to reduce attack surface
Settings > Security > Install unknown apps > Disable for all apps
🧯 If You Can't Patch
- Restrict app installations to Google Play Store only
- Use mobile device management (MDM) to enforce security policies and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If it shows Android 13 without May 2023 security patch, device is vulnerable.Check Version:
adb shell getprop ro.build.version.release && adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android version is 13 with security patch level May 5, 2023 or later in Settings > About phone > Android security update.📡 Detection & Monitoring
Log Indicators:
- Unusual broadcast receiver registrations from isolated processes
- Permission denial logs for ActivityManagerService
Network Indicators:
- None - this is a local privilege escalation
SIEM Query:
source="android_system_logs" AND ("registerReceiverWithFeature" OR "ActivityManagerService" AND "permission denied")