CVE-2019-1171
📋 TL;DR
CVE-2019-1171 is an information disclosure vulnerability in SymCrypt's OAEP decryption implementation. Attackers with local access can exploit this to obtain sensitive information that could facilitate further system compromise. This affects Windows systems using vulnerable versions of SymCrypt.
💻 Affected Systems
- Microsoft Windows
📦 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
⚠️ Risk & Real-World Impact
Worst Case
An attacker obtains cryptographic keys or other sensitive data, leading to complete system compromise through subsequent attacks.
Likely Case
Local attackers extract limited information that could assist in privilege escalation or lateral movement attacks.
If Mitigated
With proper access controls, impact is limited to information disclosure from the compromised user context.
🎯 Exploit Status
Requires local access and ability to run specially crafted application. No public exploits known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: October 2019 security updates
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1171
Restart Required: Yes
Instructions:
1. Apply October 2019 Windows security updates. 2. Restart affected systems. 3. Verify update installation via Windows Update history.
🧯 If You Can't Patch
- Restrict local user access to sensitive systems.
- Implement application whitelisting to prevent unauthorized applications.
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for October 2019 security updates. Systems without KB4517389 (Windows 10 1903) or equivalent updates are vulnerable.Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify October 2019 security updates are installed via Windows Update history or 'systeminfo' command.📡 Detection & Monitoring
Log Indicators:
- Unusual cryptographic operations in application logs
- Failed or abnormal OAEP decryption attempts
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for process creation events running unusual cryptographic tools or applications with high privilege cryptographic operations.