CVE-2023-21085
📋 TL;DR
This CVE describes a critical out-of-bounds write vulnerability in Android's NFC implementation that allows remote code execution without user interaction. Attackers within proximity can exploit this to execute arbitrary code on affected devices. All Android devices running versions 11 through 13 are vulnerable.
💻 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 attackers to install persistent malware, steal sensitive data, or join devices to botnets.
Likely Case
Local privilege escalation leading to unauthorized access to device resources and user data.
If Mitigated
Limited impact if devices are patched, NFC is disabled, or proper network segmentation prevents attacker proximity.
🎯 Exploit Status
Exploitation requires proximity to target device or access to adjacent network. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: April 2023 Android Security Bulletin
Vendor Advisory: https://source.android.com/security/bulletin/2023-04-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install April 2023 security patch. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable NFC
androidTemporarily disable NFC functionality to prevent exploitation
Settings > Connected devices > Connection preferences > NFC > Toggle OFF
🧯 If You Can't Patch
- Disable NFC functionality on all affected devices
- Implement network segmentation to limit attacker proximity access
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If version is 11, 12, 12L, or 13 without April 2023 patch, device is vulnerable.Check Version:
Settings > About phone > Android versionVerify Fix Applied:
Verify Android Security Patch Level shows 'April 5, 2023' or later in Settings > About phone > Android version.📡 Detection & Monitoring
Log Indicators:
- Unusual NFC activity logs
- Crash reports from nci_hmsgs.cc or NFC services
Network Indicators:
- Unexpected NFC communication attempts
- Abnormal Bluetooth or WiFi proximity activity
SIEM Query:
source="android_logs" AND (process="NFC" OR message="*nci_*") AND (severity="ERROR" OR severity="CRITICAL")