CVE-2021-0327
📋 TL;DR
This vulnerability allows local attackers to bypass Android's permission system by exploiting a flaw in how binder identities are restored in the ActivityManagerService. It enables local privilege escalation without requiring user interaction or additional execution privileges. Affected systems include Android devices running versions 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
An attacker gains full system-level privileges, potentially compromising the entire device, accessing sensitive data, or installing persistent malware.
Likely Case
Local malicious apps escalate privileges to access restricted system functions or user data they shouldn't have permission to reach.
If Mitigated
With proper patching, the vulnerability is eliminated; without patching, strong app vetting and device security policies can limit exploitation.
🎯 Exploit Status
Exploitation requires local access and knowledge of Android internals, but no user interaction is needed, making it feasible for determined attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin February 2021 patches
Vendor Advisory: https://source.android.com/security/bulletin/2021-02-01
Restart Required: Yes
Instructions:
1. Check for system updates in device settings. 2. Apply the February 2021 Android security patch or later. 3. Restart the device after installation.
🔧 Temporary Workarounds
Restrict app installations
allLimit installation of apps to trusted sources only to reduce the risk of malicious apps exploiting this vulnerability.
🧯 If You Can't Patch
- Monitor device for unusual app behavior or privilege escalation attempts using security tools.
- Isolate affected devices from sensitive networks and data to limit potential damage.
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version; if it's 8.1, 9, 10, or 11 and not patched with February 2021 security update, it's vulnerable.Check Version:
On Android device, use adb shell getprop ro.build.version.security_patch or check in device settings.Verify Fix Applied:
Verify the Android security patch level in Settings > About phone > Android security patch level; ensure it's dated February 2021 or later.📡 Detection & Monitoring
Log Indicators:
- Unusual ActivityManagerService logs indicating permission bypass attempts or unexpected binder identity changes.
Network Indicators:
- None, as this is a local exploit with no network activity required.
SIEM Query:
Not applicable due to local nature; focus on device logs for privilege escalation events.