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CVE-2021-42316

8.8 HIGH
Remote Code Execution

📋 TL;DR

CVE-2021-42316 is a remote code execution vulnerability in Microsoft Dynamics 365 On-Premises that allows authenticated attackers to execute arbitrary code on affected servers. This affects organizations running vulnerable versions of Dynamics 365 On-Premises, potentially compromising business data and systems.

💻 Affected Systems

Products:
  • Microsoft Dynamics 365 On-Premises
Versions: Specific versions not detailed in public advisory; refer to Microsoft's security update for exact affected versions
Operating Systems: Windows Server (as required by Dynamics 365 On-Premises)
Default Config Vulnerable: ⚠️ Yes
Notes: Requires authenticated access to the Dynamics 365 instance; on-premises deployments only (cloud versions not affected).

📦 What is this software?

Dynamics 365 by Microsoft

View all CVEs affecting Dynamics 365 →

Dynamics 365 by Microsoft

View all CVEs affecting Dynamics 365 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise allowing attackers to execute arbitrary code, steal sensitive business data, deploy ransomware, and pivot to other internal systems.

🟠

Likely Case

Data exfiltration, installation of backdoors, and lateral movement within the organization's network.

🟢

If Mitigated

Limited impact due to network segmentation, strong authentication controls, and monitoring preventing successful exploitation.

🌐 Internet-Facing: HIGH if Dynamics 365 is exposed to the internet, as authenticated attackers could exploit remotely.
🏢 Internal Only: HIGH as authenticated internal users or compromised accounts could exploit the vulnerability.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ✅ No
Complexity: MEDIUM

Requires authenticated access; exploitation details not publicly disclosed by Microsoft.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Apply the security update from Microsoft's November 2021 Patch Tuesday or later

Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42316

Restart Required: Yes

Instructions:

1. Download the security update from Microsoft Update Catalog. 2. Apply the update to all affected Dynamics 365 On-Premises servers. 3. Restart the servers as required. 4. Test functionality after patching.

🔧 Temporary Workarounds

Network Segmentation

all

Restrict access to Dynamics 365 servers to only necessary users and systems using firewall rules.

Enhanced Authentication Controls

all

Implement multi-factor authentication and strong password policies for all Dynamics 365 users.

🧯 If You Can't Patch

  • Implement strict network segmentation to isolate Dynamics 365 servers from critical systems
  • Enhance monitoring and logging for suspicious activities on Dynamics 365 servers

🔍 How to Verify

Check if Vulnerable:

Check Dynamics 365 version against Microsoft's security advisory; review patch installation status in Windows Update history.

Check Version:

Check Dynamics 365 version through the application interface or server configuration files.

Verify Fix Applied:

Verify the security update is installed via Control Panel > Programs > View installed updates, and confirm version matches patched release.

📡 Detection & Monitoring

Log Indicators:

  • Unusual authentication patterns, unexpected process executions, or file modifications on Dynamics 365 servers

Network Indicators:

  • Suspicious outbound connections from Dynamics 365 servers to unknown IPs

SIEM Query:

Example: search for 'Dynamics 365' AND ('process creation' OR 'file modification') from non-standard users

📊 Metadata

CVE ID: CVE-2021-42316
CVSS v3 Score: 8.8 (HIGH)
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published: November 10, 2021
Last Updated: November 21, 2024

🔗 References

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