CVE-2019-1151
📋 TL;DR
This is a remote code execution vulnerability in Windows font library that allows attackers to execute arbitrary code by tricking users into viewing malicious embedded fonts. It affects Windows systems with vulnerable font handling components. Attackers can gain full system control if successful.
💻 Affected Systems
- Microsoft Windows
📦 What is this software?
Office by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 7 by Microsoft
Windows 8.1 by Microsoft
Windows Rt 8.1 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with administrative privileges, allowing installation of malware, data theft, and complete system control.
Likely Case
Limited user account compromise through phishing emails or malicious websites, potentially leading to lateral movement within networks.
If Mitigated
Limited impact with proper user training, application whitelisting, and network segmentation preventing widespread compromise.
🎯 Exploit Status
Exploit requires user interaction but technical complexity is low once malicious content is delivered.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: July 2019 security updates
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1151
Restart Required: Yes
Instructions:
1. Apply Windows Update. 2. Install July 2019 security updates. 3. Restart system. 4. Verify update installation.
🔧 Temporary Workarounds
Disable embedded font parsing
windowsPrevent Windows from processing embedded fonts in documents
reg add "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts" /v "DisableFontParsing" /t REG_DWORD /d 1 /f
Block font file extensions
allPrevent delivery of font files via email
🧯 If You Can't Patch
- Implement application whitelisting to prevent unauthorized executables
- Use network segmentation to limit lateral movement if compromised
🔍 How to Verify
Check if Vulnerable:
Check Windows version and verify July 2019 security updates are not installedCheck Version:
wmic os get caption, version, buildnumberVerify Fix Applied:
Verify July 2019 security updates are installed via Windows Update history📡 Detection & Monitoring
Log Indicators:
- Unexpected font library process crashes
- Suspicious document openings with embedded fonts
Network Indicators:
- Unusual outbound connections after document viewing
- Font file downloads from untrusted sources
SIEM Query:
EventID=1000 Source="Windows Error Reporting" AND ProcessName contains "font"🔗 References
- http://packetstormsecurity.com/files/154092/Microsoft-Font-Subsetting-DLL-ReadAllocFormat12CharGlyphMapList-Heap-Corruption.html
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1151
- http://packetstormsecurity.com/files/154092/Microsoft-Font-Subsetting-DLL-ReadAllocFormat12CharGlyphMapList-Heap-Corruption.html
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1151
