CVE-2021-0573
📋 TL;DR
CVE-2021-0573 is an out-of-bounds write vulnerability in Android's ASF extractor component that allows local privilege escalation without user interaction. Attackers can exploit this to gain elevated system privileges on vulnerable Android devices. This affects Android devices with specific System-on-Chip (SoC) implementations.
💻 Affected Systems
- Android devices with specific System-on-Chip implementations
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to execute arbitrary code with system privileges, install persistent malware, access sensitive data, and bypass all security controls.
Likely Case
Local privilege escalation allowing malware to gain higher privileges than initially obtained, potentially enabling data theft, surveillance capabilities, or persistence mechanisms.
If Mitigated
Limited impact with proper patch management and security controls in place, though unpatched devices remain vulnerable to local attacks.
🎯 Exploit Status
Exploitation requires local access to the device. No public proof-of-concept has been released, but the vulnerability is well-documented in Android security bulletins.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level August 2021 or later
Vendor Advisory: https://source.android.com/security/bulletin/2021-08-01
Restart Required: Yes
Instructions:
1. Check for system updates in Android Settings > System > System update. 2. Install the August 2021 or later security patch. 3. Restart the device after installation. 4. Verify the patch level in Settings > About phone > Android security patch level.
🔧 Temporary Workarounds
Disable vulnerable media components
androidRestrict or disable ASF file processing through device policies or configuration changes
Application sandboxing
androidImplement strict app isolation and permission controls to limit potential privilege escalation impact
🧯 If You Can't Patch
- Implement strict application vetting and only install apps from trusted sources like Google Play Store
- Use mobile device management (MDM) solutions to enforce security policies and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android security patch level. If date is before August 2021, device is likely vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android security patch level shows August 2021 or later date in Settings > About phone > Android security patch level.📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation attempts in system logs
- ASF extractor process crashes or abnormal behavior
- Unexpected system service restarts
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for: 'ASF extractor crash', 'privilege escalation', or 'CVE-2021-0573' in Android system logs