CVE-2021-0557
📋 TL;DR
This CVE describes an integer overflow vulnerability in Android's ABuffer.cpp that allows out-of-bounds writes. When exploited, it could lead to remote code execution without requiring additional privileges, though user interaction is needed. All Android 11 devices are affected until patched.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Remote attacker gains full control of device through code execution, potentially installing malware, stealing data, or joining botnets.
Likely Case
Targeted attacks against specific users via malicious apps or content, leading to data theft or surveillance.
If Mitigated
With proper patching and security controls, impact is limited to denial of service or application crashes.
🎯 Exploit Status
Requires user interaction (opening malicious content). No public exploit code known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level 2021-06-01 or later
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2021-06-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > Advanced > System update. 2. Install Android Security Patch Level 2021-06-01 or later. 3. Reboot device after installation.
🔧 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
Update Google Play Protect
androidEnsure Google Play Protect is enabled and updated for malware detection
Settings > Security > Google Play Protect > Scan device for security threats
🧯 If You Can't Patch
- Isolate vulnerable devices from critical networks and sensitive data
- Implement application allowlisting to prevent execution of unauthorized apps
🔍 How to Verify
Check if Vulnerable:
Check Settings > About phone > Android version (if Android 11) and Security patch level (if before 2021-06-01)Check Version:
adb shell getprop ro.build.version.release && adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Security patch level is 2021-06-01 or later in Settings > About phone📡 Detection & Monitoring
Log Indicators:
- Crash logs from media framework (ABuffer.cpp)
- Unexpected process termination in media services
Network Indicators:
- Unusual outbound connections from media processes
- Traffic to known malicious domains
SIEM Query:
process_name:media.* AND (event_type:crash OR exit_code:139)