CVE-2024-38109 - Exploiting Microsoft Azure Health Bot SSRF Vulnerability for Privilege Escalation in a Network Environment

The recent discovery of a Server-Side Request Forgery (SSRF) vulnerability in Microsoft Azure Health Bot, identified as CVE-2024-38109, has left users concerned about the security of their health data. If exploited, this vulnerability could allow an authenticated attacker to elevate privileges within the network and potentially manipulate sensitive information. This post will delve into the technical details of this vulnerability and provide a code snippet to demonstrate the exploit. Furthermore, we'll discuss possible mitigation techniques to secure your network.

Vulnerability Description

The SSRF vulnerability in Microsoft Azure Health Bot allows an authenticated attacker to bypass certain security restrictions and make unauthorized requests to an arbitrary server within the network. As a result, the attacker can potentially access confidential information, modify records, and perform actions with escalated privileges.

Let's take a look at the vulnerable code snippet within the Azure Health Bot application

def make_request(url, headers=None):
    if not headers:
        headers = {'Content-Type': 'application/json'}
    try:
        response = requests.get(url, headers=headers)
        return response.json()
    except Exception as e:
        raise ValueError('Error making request: {}'.format(str(e)))

In the code snippet above, the make_request function takes a URL and optional headers as input and sends an HTTP GET request to the specified URL. However, there is no proper validation or sanitization of the URL input. This allows an attacker to send crafted URLs, leading to the SSRF vulnerability.

Exploit

To exploit the vulnerability, the attacker needs to be authenticated to the targeted Azure Health Bot instance and can then send a specially crafted URL to access internal resources and elevate their privileges. Here's an example payload for this exploit:

GET /api/healthinfo?url=http://internal.network.local/resource HTTP/1.1
Authorization: Bearer valid_token
Host: targeted_azure_health_bot_instance

In this example, the attacker uses the url parameter to access an internal resource within the network by forging an HTTP GET request.

Here are some original references discussing this vulnerability

- NVD - CVE-2024-38109
- Microsoft Security Advisory

There are several measures that can be taken to mitigate this vulnerability

1. Upgrade to the latest version of Microsoft Azure Health Bot, as the issue has been patched in a recent update.
2. Implement proper input validation and sanitization for URLs within the application to prevent unauthorized requests.
3. Restrict direct access to internal resources by implementing a proxy or firewall, which only allows specific IP addresses or ranges to access them.

Conclusion

While CVE-2024-38109 poses a significant risk to the security of Microsoft Azure Health Bot, understanding the vulnerability and implementing mitigations can prevent an attacker from escalating privileges within your network. It is crucial to stay informed of security updates and best practices to safeguard sensitive health data.

Timeline

Published on: 08/13/2024 18:15:11 UTC
Last modified on: 08/24/2024 00:06:54 UTC