CVE-2018-9397
📋 TL;DR
CVE-2018-9397 is an out-of-bounds write vulnerability in the MediaTek WMT device driver that allows local privilege escalation. Attackers with system execution privileges can exploit this without user interaction to gain elevated access. This affects Android devices using MediaTek chipsets.
💻 Affected Systems
- Android devices with MediaTek chipsets
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary code with kernel privileges, potentially installing persistent malware or accessing all device data.
Likely Case
Local privilege escalation allowing attackers to bypass security restrictions and gain elevated system access on compromised devices.
If Mitigated
Limited impact if devices are properly patched and have security controls like SELinux enforcing mode enabled.
🎯 Exploit Status
Requires system execution privileges for initial access. The vulnerability is in a kernel driver, making exploitation more complex than user-space vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android security patch level 2018-06-05 or later
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2018-06-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > Advanced > System update. 2. Apply the June 2018 or later security patch. 3. Reboot the device after installation.
🔧 Temporary Workarounds
Disable unnecessary kernel modules
linuxRemove or disable the vulnerable WMT driver module if not required for device functionality
rmmod wmt
echo 'blacklist wmt' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Restrict device access to trusted users only and monitor for suspicious privilege escalation attempts
- Implement application whitelisting to prevent execution of unauthorized or malicious applications
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android security patch level. If date is before June 2018, device is vulnerable.Check Version:
getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level shows 2018-06-05 or later. Check that the WMT driver version has been updated.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Unexpected privilege escalation attempts in audit logs
- SELinux denials related to WMT driver
Network Indicators:
- Unusual outbound connections following local privilege escalation
SIEM Query:
source="android_logs" AND ("WMT" OR "wmt") AND ("panic" OR "oops" OR "privilege")