CVE-2020-27050
📋 TL;DR
This CVE describes a heap buffer overflow vulnerability in Android's NFC stack that allows local privilege escalation. An attacker could exploit this to gain elevated system privileges on affected Android devices. Only Android 11 devices are affected, requiring user interaction for exploitation.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to execute arbitrary code with system privileges, install persistent malware, access all user data, and bypass security controls.
Likely Case
Local privilege escalation allowing malware to gain higher privileges than initially obtained, potentially enabling data theft or further system compromise.
If Mitigated
Limited impact due to user interaction requirement and Android's security sandboxing, with potential containment to the affected process.
🎯 Exploit Status
Exploitation requires user to scan a malicious NFC tag. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level 2020-12-01 or later
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2020-12-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > Advanced > System update. 2. Install the December 2020 security patch or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable NFC
androidTemporarily disable NFC functionality to prevent exploitation via malicious tags
Restrict NFC usage
androidOnly use NFC with trusted sources and avoid scanning unknown NFC tags
🧯 If You Can't Patch
- Disable NFC functionality completely in device settings
- Implement strict physical security controls to prevent unauthorized NFC tag scanning
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If version is 11 and security patch level is before December 2020, 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 2020-12-01 or later in Settings > About phone > Android security patch level.📡 Detection & Monitoring
Log Indicators:
- Unusual NFC tag scanning activity
- Process crashes in com.android.nfc
- Privilege escalation attempts
Network Indicators:
- N/A - Local vulnerability
SIEM Query:
N/A - Primarily local device logs would need monitoring