Recently, an issue was discovered in LIVEBOX Collaboration vDesk, versions up to v031. This issue, identified as CVE-2022-45177, is related to Observable Response Discrepancies in the application, specifically on the following endpoints:

- /api/v1/vdeskintegration/user/isenableuser
- /api/v1/sharedsearch?search={NAME]+{SURNAME}
- /login

The bug allows unauthorized actors to acquire internal state information from the application, leading to information disclosure. This post will detail the nature of the vulnerability, provide examples of the coding pitfalls, and link to the original references.

The Issue at Hand

LIVEBOX Collaboration vDesk application is designed to help teams work together online by providing a virtual desktop environment, complete with tools, resources, and shared services. Unfortunately, a vulnerability has come to light in the web application that could allow unauthorized actors to obtain sensitive information about the internal state of the app.

The issue arises from the application providing varying responses to incoming requests. Different response types can be observed for the same request, which leads to information disclosure. Unauthorized actors can exploit this Observable Response Discrepancy to gain insights into the application’s inner workings.

The affected endpoints in LIVEBOX Collaboration vDesk are

1. /api/v1/vdeskintegration/user/isenableuser
2. /api/v1/sharedsearch?search={NAME]+{SURNAME}
3. /login

An example of the Observable Response Discrepancy can be seen in the following code snippet related to the /api/v1/vdeskintegration/user/isenableuser endpoint:

# Sample vulnerable code snippet
def is_user_enabled(username):
    user = get_user(username)
    if user is None:
        # Returning a status code 400 (Bad Request)
        return Response("User not found", status=400)
    elif not user.is_enabled():
        # Returning a status code 403 (Forbidden)
        return Response("User is disabled", status=403)
    else:
        # Returning a status code 200 (OK)
        return Response("User is enabled", status=200)

In this example, different status codes are returned depending on the state of the user. An attacker can deduce the existence of a user or their account status by observing these distinct responses. Ideally, the application should not reveal this information to unauthorized users.

Mitigation and Recommendations

To secure this vulnerability, developers should avoid assigning different and identifiable responses for the same input. Instead, consider using a generic response message and the same status code to prevent unintended information disclosure. The following code snippet demonstrates a secure way to handle similar scenarios:

# Secure code snippet example
def is_user_enabled(username):
    user = get_user(username)
    if user is None or not user.is_enabled():
        # Returning a status code 403 (Forbidden) for both cases
        return Response("Forbidden", status=403)
    else:
        # Returning a status code 200 (OK)
        return Response("User is enabled", status=200)

In the secure example above, a single Forbidden message is returned with a status code of 403, making it difficult for unauthorized actors to deduce any internal state information.

Healthy coding practices should include regular code reviews, especially for critical systems handling sensitive data. Make sure to stay up-to-date with the latest security patches and updates for the LIVEBOX Collaboration vDesk application.

For more information on CVE-2022-45177, please refer to the following sources

- CVE Details - CVE-2022-45177
- NVD - CVE-2022-45177

Stay vigilant and keep your systems patched and up-to-date to ensure the best security posture possible!

Timeline

Published on: 02/21/2024 16:15:49 UTC
Last modified on: 03/19/2024 16:48:49 UTC