CVE-2018-9411
📋 TL;DR
This vulnerability in Android's ClearKey CAS plugin allows remote attackers to execute arbitrary code through an out-of-bounds write during decryption. It affects Android devices using the affected media framework components. User interaction is required for exploitation, typically through playing malicious media content.
💻 Affected Systems
- Android OS
📦 What is this software?
Android by Google
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with system-level privileges leading to complete device compromise, data theft, and persistent backdoor installation.
Likely Case
Application crash or limited code execution within media framework context, potentially leading to data leakage or further privilege escalation.
If Mitigated
Application crash with no code execution if proper sandboxing and exploit mitigations are in place.
🎯 Exploit Status
Exploitation requires user to play malicious media content. The vulnerability is in the media framework's decryption process.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level 2018-07-01 or later
Vendor Advisory: https://source.android.com/security/bulletin/2018-07-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > Advanced > System update. 2. Install the July 2018 Android security patch. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable ClearKey CAS
androidPrevent use of ClearKey CAS DRM by disabling or removing the plugin
adb shell pm disable com.android.clearkey
Restrict Media Sources
allOnly allow media playback from trusted sources and disable unknown sources
🧯 If You Can't Patch
- Implement application sandboxing and exploit mitigations (ASLR, DEP)
- Monitor for abnormal media framework crashes or unexpected process behavior
🔍 How to Verify
Check if Vulnerable:
Check Android version and security patch level in Settings > About phone > Android versionCheck Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level is 2018-07-01 or later in Settings > About phone > Android security patch level📡 Detection & Monitoring
Log Indicators:
- Media framework crashes (logcat entries containing ClearKeyCasPlugin)
- Unexpected process spawns from media services
Network Indicators:
- Downloads of encrypted media files from untrusted sources
- Unusual network traffic from media framework processes
SIEM Query:
process_name:"mediaserver" AND (event_type:crash OR parent_process:unexpected)