CVE-2023-21124
📋 TL;DR
This vulnerability allows local privilege escalation on Android devices through unsafe deserialization in the 'run of multiple files' component. Attackers can exploit this without user interaction to gain elevated privileges. Affects Android 11, 12, 12L, and 13.
💻 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
Complete device compromise allowing attacker to execute arbitrary code with system privileges, access sensitive data, and persist on the device.
Likely Case
Local attacker gains elevated privileges to access protected system resources, install malicious apps, or modify system settings.
If Mitigated
Limited impact with proper security updates applied and device security features enabled.
🎯 Exploit Status
Exploitation requires local access to the device. No user interaction needed once access is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: June 2023 Android Security Bulletin updates
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. 3. Restart 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
Enable Google Play Protect
androidEnable scanning for harmful apps
Settings > Security > Google Play Protect > Scan device for security threats
🧯 If You Can't Patch
- Restrict physical access to devices and implement strict app installation policies
- Monitor for suspicious app behavior and 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 Security patch levelVerify Fix Applied:
Verify Android version and security patch level in Settings > About phone. Look for 'Android security patch level: June 5, 2023' or later.📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation attempts in system logs
- Suspicious deserialization events
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
Not applicable - local device vulnerability without network indicators