CVE-2019-1187
📋 TL;DR
This is a denial of service vulnerability in Microsoft's XmlLite runtime library that improperly parses XML input. An attacker can crash XML applications by sending specially crafted XML requests. Any system running affected Microsoft software that processes XML is potentially vulnerable.
💻 Affected Systems
- Microsoft Windows
- Microsoft Office
- Other Microsoft products using XmlLite.dll
📦 What is this software?
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
Complete denial of service for XML-dependent applications, potentially disrupting business operations or critical services.
Likely Case
Application crashes or hangs when processing malicious XML input, requiring restart of affected services.
If Mitigated
Minimal impact with proper network segmentation and XML input validation in place.
🎯 Exploit Status
Exploitation requires crafting specific XML payloads that trigger the parsing vulnerability. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: August 2019 security updates (KB4512508 for Windows 10 1903, etc.)
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1187
Restart Required: Yes
Instructions:
1. Apply August 2019 Microsoft security updates via Windows Update. 2. For enterprise environments, deploy updates through WSUS or SCCM. 3. Restart systems after update installation.
🔧 Temporary Workarounds
XML Input Validation
allImplement strict XML schema validation and input sanitization for XML processing applications.
Network Segmentation
allRestrict access to XML processing endpoints to trusted networks only.
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block malformed XML requests
- Disable or restrict XML processing features in applications where possible
🔍 How to Verify
Check if Vulnerable:
Check if XmlLite.dll version is prior to August 2019 updates. Vulnerable systems will have XmlLite.dll with version numbers before the patched version.Check Version:
powershell: Get-Item C:\Windows\System32\XmlLite.dll | Select-Object VersionInfoVerify Fix Applied:
Verify XmlLite.dll file version is updated to August 2019 or later. Check Windows Update history for August 2019 security updates.📡 Detection & Monitoring
Log Indicators:
- Application crashes related to XML parsing
- High volume of malformed XML requests
- XmlLite.dll related error messages in application logs
Network Indicators:
- Unusual XML payloads to XML processing endpoints
- Repeated XML requests causing service disruption
SIEM Query:
source="application_logs" AND ("XmlLite" OR "XML parsing error" OR "access violation") AND severity=ERROR