CVE-2021-0473
📋 TL;DR
This CVE describes a double-free vulnerability in Android's NFC stack that could allow remote code execution without user interaction. An attacker could exploit this by sending malicious NFC data to an affected device, potentially gaining control over it. All Android devices running versions 8.1 through 11 are affected.
💻 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
Remote attacker gains full control of device via NFC, installs malware, steals data, or bricks device without user interaction.
Likely Case
Device crashes or becomes unstable due to memory corruption, potentially leading to denial of service.
If Mitigated
With NFC disabled or device not in proximity to attacker, no impact occurs.
🎯 Exploit Status
Exploitation requires NFC proximity and knowledge of the vulnerability, but no authentication or user interaction.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level May 2021 or later
Vendor Advisory: https://source.android.com/security/bulletin/2021-05-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > Advanced > System update. 2. Install Android Security Patch Level May 2021 or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable NFC
androidTurn off NFC functionality to prevent exploitation via this vector
Settings > Connected devices > Connection preferences > NFC > Toggle OFF
🧯 If You Can't Patch
- Disable NFC functionality completely on all affected devices
- Implement physical security controls to prevent unauthorized NFC devices near corporate devices
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If version is 8.1, 9, 10, or 11, check Security patch level. If before May 2021, device is vulnerable.Check Version:
adb shell getprop ro.build.version.release && adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android Security Patch Level is May 2021 or later in Settings > About phone > Android security update.📡 Detection & Monitoring
Log Indicators:
- NFC service crashes in logcat
- Memory corruption errors in system logs
- Unexpected NFC tag processing failures
Network Indicators:
- N/A (exploitation is local via NFC)
SIEM Query:
N/A (requires physical device logs)