CVE-2021-39780
📋 TL;DR
CVE-2021-39780 allows attackers to bypass developer settings requirements for capturing system traces in Android 12L due to a missing permission check. This could lead to local privilege escalation without requiring additional execution privileges, though user interaction is needed for exploitation. Only Android 12L devices are affected.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains elevated privileges to access sensitive system trace data, potentially exposing debugging information, application data, or system state details that should be restricted.
Likely Case
Malicious app tricks user into granting trace capture access, allowing collection of debugging information from other apps or system components.
If Mitigated
With proper Android security updates applied, the vulnerability is completely patched with no residual risk.
🎯 Exploit Status
Requires user interaction and local access. No public exploit code has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android security updates for March 2022 or later
Vendor Advisory: https://source.android.com/security/bulletin/android-12l
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install the March 2022 or later security update. 3. Restart device after installation.
🔧 Temporary Workarounds
Disable Developer Options
androidTurn off Developer Options to reduce attack surface
Settings > System > Developer Options > Toggle off
Restrict App Installations
androidOnly install apps from trusted sources like Google Play Store
Settings > Security > Install unknown apps > Disable for all apps
🧯 If You Can't Patch
- Disable Developer Options completely on affected devices
- Implement strict app installation policies and only allow apps from trusted sources
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About Phone > Android Version. If it shows Android 12L and security patch level is before March 2022, device is vulnerable.Check Version:
Settings > About Phone > Android VersionVerify Fix Applied:
Verify Android version is 12L with security patch level March 2022 or later in Settings > About Phone > Android Version.📡 Detection & Monitoring
Log Indicators:
- Unexpected system trace captures
- Permission bypass attempts in system logs
- Developer options access without proper authorization
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Look for Android system logs containing 'Traceur' permission bypass attempts or unexpected trace capture events