CVE-2023-21287
📋 TL;DR
This CVE describes a type confusion vulnerability in Android's FreeType library that allows remote code execution without user interaction. Attackers can exploit this to execute arbitrary code on affected devices. All Android devices using vulnerable FreeType versions are potentially affected.
💻 Affected Systems
- Android devices with FreeType library
📦 What is this software?
Android by Google
Android by Google
Android by Google
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise allowing attacker to install malware, steal data, or join botnets
Likely Case
Remote code execution leading to data theft, surveillance, or ransomware deployment
If Mitigated
Limited impact if devices are patched, isolated, or have exploit mitigations enabled
🎯 Exploit Status
Type confusion vulnerabilities often lead to reliable exploitation; no authentication required
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: August 2023 Android Security Patch or later
Vendor Advisory: https://source.android.com/security/bulletin/2023-08-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install August 2023 or later security patch. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable untrusted font sources
androidPrevent loading fonts from untrusted sources to reduce attack surface
🧯 If You Can't Patch
- Network segmentation to isolate vulnerable devices
- Implement application allowlisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android versionCheck Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch date is August 2023 or later in device settings📡 Detection & Monitoring
Log Indicators:
- Unexpected FreeType library crashes
- Suspicious font file processing
Network Indicators:
- Unusual font file downloads from external sources
SIEM Query:
process_name:"freetype" AND (event_type:crash OR suspicious_file_extension:(".ttf" ".otf"))🔗 References
- https://android.googlesource.com/platform/external/freetype/+/a79e80a25874dacaa266906a9048f13d4bac41c6
- https://source.android.com/security/bulletin/2023-08-01
- https://android.googlesource.com/platform/external/freetype/+/a79e80a25874dacaa266906a9048f13d4bac41c6
- https://source.android.com/security/bulletin/2023-08-01
