CVE-2021-1048
📋 TL;DR
CVE-2021-1048 is a use-after-free vulnerability in the Android kernel's eventpoll subsystem that allows local privilege escalation. An attacker can exploit this to gain root access on affected Android devices without requiring user interaction. This affects Android devices running vulnerable kernel versions.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise with root privileges, allowing installation of persistent malware, data theft, and bypassing all security controls.
Likely Case
Local privilege escalation to root, enabling attackers to install malicious apps, access sensitive data, and modify system settings.
If Mitigated
Limited impact if devices are patched, but unpatched devices remain fully vulnerable to local attackers.
🎯 Exploit Status
Exploitation requires local access to the device. The vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android security patch level November 2021 or later
Vendor Advisory: https://source.android.com/security/bulletin/2021-11-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install the November 2021 or later security patch. 3. Reboot the device after installation.
🔧 Temporary Workarounds
No effective workarounds
allThis is a kernel-level vulnerability that requires patching. No configuration changes or workarounds can mitigate the vulnerability.
🧯 If You Can't Patch
- Restrict physical access to devices and implement strict app installation policies
- Monitor for suspicious privilege escalation attempts and unusual root access patterns
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android version > Security patch level. If earlier than November 2021, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level shows November 2021 or later date in Settings > About phone > Android version > Security patch level.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs, unusual privilege escalation attempts, unexpected root access in system logs
Network Indicators:
- Unusual outbound connections from device after potential compromise
SIEM Query:
source="android_logs" AND (event_type="privilege_escalation" OR process="su" OR user="root")