CVE-2021-39764
📋 TL;DR
This vulnerability in Android Settings allows an attacker to spoof app names due to improper input validation, potentially leading to local privilege escalation. It affects Android 12L devices and requires user interaction for exploitation.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
An attacker could trick users into granting permissions to a malicious app disguised as a legitimate one, leading to full device compromise.
Likely Case
Malicious apps could gain elevated permissions by impersonating trusted applications, potentially accessing sensitive data.
If Mitigated
With proper app vetting and user awareness, the risk is reduced to minimal privilege escalation attempts.
🎯 Exploit Status
Requires user interaction and local app installation; no public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level March 2022 or later
Vendor Advisory: https://source.android.com/security/bulletin/android-12l
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > System update. 2. Install the March 2022 or later security patch. 3. Reboot the device.
🔧 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
- Only install apps from trusted sources like Google Play Store
- Review app permissions carefully before granting access
🔍 How to Verify
Check if Vulnerable:
Check Android version: Settings > About phone > Android version. If it shows 12L and security patch level is before March 2022, device is vulnerable.Check Version:
adb shell getprop ro.build.version.releaseVerify Fix Applied:
Verify security patch level is March 2022 or later in Settings > About phone > Android security update.📡 Detection & Monitoring
Log Indicators:
- Unusual app permission requests
- App name mismatches in system logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
Not applicable for local device vulnerabilities