CVE-2021-0708
📋 TL;DR
CVE-2021-0708 is a local privilege escalation vulnerability in Android's ActivityManagerShellCommand that allows attackers to delete system files without requiring user interaction. This confused deputy attack could lead to system compromise or denial of service. Affected devices include Android 8.1 through 11.
💻 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 system compromise through deletion of critical system files, potentially bricking the device or enabling persistent malware installation.
Likely Case
Local privilege escalation allowing attackers to gain elevated permissions, access sensitive data, or disrupt device functionality.
If Mitigated
Limited impact with proper patch management and security controls, though physical access to device remains a risk factor.
🎯 Exploit Status
Exploitation requires local access to device shell or ability to execute code. No user interaction needed once access is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin October 2021 patches
Vendor Advisory: https://source.android.com/security/bulletin/2021-10-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install the October 2021 security patch or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Restrict shell access
androidLimit access to Android Debug Bridge (ADB) and developer options to prevent local exploitation
adb shell settings put global development_settings_enabled 0
adb shell settings put global adb_enabled 0
Disable unnecessary permissions
androidReview and restrict app permissions, especially for apps requesting shell or system-level access
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized physical access to devices
- Use mobile device management (MDM) solutions to enforce security policies and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check Android build fingerprint: Settings > About phone > Build number. If version is 8.1-11 without October 2021 patches, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android security patch level is October 2021 or later: Settings > About phone > Android security patch level📡 Detection & Monitoring
Log Indicators:
- Unusual ActivityManagerShellCommand executions
- Suspicious file deletion operations in system directories
- Unexpected privilege escalation attempts
Network Indicators:
- Not applicable - local exploitation only
SIEM Query:
source="android_logs" AND ("ActivityManagerShellCommand" OR "runDumpHeap") AND ("delete" OR "privilege")