CVE-2020-16862
📋 TL;DR
This is a remote code execution vulnerability in Microsoft Dynamics 365 (on-premises) where improper input sanitization allows authenticated attackers to execute arbitrary code. The vulnerability affects on-premises Dynamics 365 deployments, allowing attackers to run code with SQL service account privileges. Organizations using vulnerable on-premises Dynamics 365 installations are affected.
💻 Affected Systems
- Microsoft Dynamics 365 (on-premises)
📦 What is this software?
Dynamics 365 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the Dynamics server, data exfiltration, lateral movement within the network, and persistent backdoor installation.
Likely Case
Data theft, business disruption, and potential ransomware deployment affecting Dynamics operations.
If Mitigated
Limited impact due to network segmentation, minimal service account privileges, and proper input validation controls.
🎯 Exploit Status
Requires authenticated access to the Dynamics server; exploitation involves specially crafted web requests.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply Microsoft security update for Dynamics 365 (on-premises)
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16862
Restart Required: Yes
Instructions:
1. Download the security update from Microsoft Update Catalog. 2. Apply the update to all affected Dynamics 365 servers. 3. Restart the servers as required. 4. Test Dynamics functionality post-patch.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to Dynamics servers to only authorized users and systems
Input Validation Enhancement
allImplement additional input validation at web application firewall or proxy level
🧯 If You Can't Patch
- Implement strict network access controls to limit who can reach Dynamics servers
- Monitor for unusual SQL service account activity and web request patterns
🔍 How to Verify
Check if Vulnerable:
Check Dynamics 365 version against Microsoft security bulletin; verify if security update is appliedCheck Version:
Check Dynamics 365 version through administrative interface or server configurationVerify Fix Applied:
Confirm security update is installed via Windows Update history or patch management system📡 Detection & Monitoring
Log Indicators:
- Unusual web request patterns to Dynamics endpoints
- SQL service account executing unexpected processes
- Failed authentication attempts followed by successful exploitation
Network Indicators:
- Unusual outbound connections from Dynamics server
- Suspicious HTTP requests to Dynamics web services
SIEM Query:
source="dynamics_server" AND (event_type="web_request" AND request_uri CONTAINS suspicious_pattern) OR (process_name="sqlservr.exe" AND parent_process!="expected_parent")