CVE-2020-16860
📋 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 SQL service account contexts, potentially compromising the entire Dynamics server and associated databases. Only on-premises deployments of Microsoft Dynamics 365 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 and associated SQL databases, allowing data theft, destruction, or ransomware deployment across the entire Dynamics environment.
Likely Case
Attacker gains SQL service account privileges, enabling data exfiltration, privilege escalation, and lateral movement within the network.
If Mitigated
Limited impact due to network segmentation, minimal SQL service account privileges, and proper input validation controls.
🎯 Exploit Status
Requires authenticated access and specially crafted web requests. No public exploit code was mentioned in the advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific patch versions
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16860
Restart Required: Yes
Instructions:
1. Apply the latest security update from Microsoft for Dynamics 365 (on-premises). 2. Restart the Dynamics server and any dependent services. 3. Verify the patch is applied correctly.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to Dynamics servers to only authorized users and systems using firewall rules.
Least Privilege for SQL Service Account
windowsReduce SQL service account privileges to minimum required for Dynamics operations.
🧯 If You Can't Patch
- Implement strict input validation and sanitization at the application layer
- Monitor for unusual SQL service account activity and failed authentication attempts
🔍 How to Verify
Check if Vulnerable:
Check Dynamics 365 version against Microsoft's security advisory; vulnerable if running an affected on-premises version without the patch.Check Version:
Check Dynamics 365 version in application settings or via PowerShell: Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like '*Dynamics*'}Verify Fix Applied:
Verify patch installation through Windows Update history or Dynamics version check; ensure version matches patched release.📡 Detection & Monitoring
Log Indicators:
- Unusual SQL service account activity
- Failed authentication attempts followed by successful ones
- Suspicious web requests to Dynamics endpoints
Network Indicators:
- Unusual outbound connections from Dynamics server
- SQL traffic from unexpected sources
SIEM Query:
source="dynamics_server" AND (event_id=4625 OR event_id=4688) AND user="SQLServiceAccount"