CVE-2023-24486: Vulnerability in the Citrix Workspace App for Linux Could Allow Unauthorized Access to Virtual Apps and Desktops Sessions

A recently discovered vulnerability in the Citrix Workspace app for Linux, assigned the Common Vulnerabilities and Exposures (CVE) identifier CVE-2023-24486, could potentially allow a local attacker to gain unauthorized access to Citrix Virtual Apps and Desktops sessions of another user on the same computer where an Independent Computing Architecture (ICA) session is initiated. In this comprehensive article, we cover the details of the vulnerability, provide a code snippet demonstrating how the exploit might be triggered, and include links to the original references and resources.

Exploit Details

To exploit this vulnerability, a malicious user would need to have physical access to the affected Linux machine where the Citrix Workspace app is installed. The attacker could then leverage the fact that the ICA session launched on the same computer allows multiple users to initiate a connection to the same Citrix Virtual Apps and Desktops environment.

With this access, a well-informed attacker might manipulate the session's file permissions or codes in a way that enables unauthorized access to an actively running ICA session initiated by another user. This would effectively compromise the integrity and security of Citrix Virtual Apps and Desktops environment, leading to potential unauthorized access to sensitive information and resources.

Code Snippet

The following Python code snippet demonstrates how file permissions could potentially be modified, providing a malicious user the ability to access another user's Citrix Virtual Apps and Desktops session. In this specific scenario, the culprit starts by intercepting the session data and modifying the session file permissions to allow access.

import os
import sys

# Function to change the permissions (mode) of the session file
def change_permissions(filepath, mode):
    try:
        os.chmod(filepath, mode)
    except Exception as e:
        print(f"Error changing permissions: {e}")

# Main script
def main():
    # The path to the session file (replace with the actual path)
    session_file = "/path/to/session/ica"

    # Check if the session file exists and is accessible
    if not os.path.isfile(session_file):
        print(f"The path {session_file} does not exist or is not accessible.")
        sys.exit(1)

    # Change the session file's permissions to allow the attacker access
    change_permissions(session_file, o777)
    
    # Additional exploit code would be inserted here...

if __name__ == "__main__":
    main()

Note that this code snippet is solely for demonstration purposes and should not be used maliciously.

Original References

1. Citrix official security advisory for CVE-2023-24486: https://support.citrix.com/article/CTX######
 2. CVE-2023-24486 details from the National Vulnerability Database (NVD): https://nvd.nist.gov/vuln/detail/CVE-2023-24486

Mitigation and Conclusion

To mitigate this vulnerability, Citrix Workspace app users on Linux machines must ensure they're using the latest version that includes the necessary security updates. Additionally, users are urged to maintain physical control over their machines, preventing unauthorized individuals from gaining access to their systems.

In conclusion, CVE-2023-24486 is a significant vulnerability in the Citrix Workspace app for Linux that could potentially have severe consequences if system security is compromised. By maintaining an up-to-date Citrix Workspace app and ensuring the physical security of a Linux machine, users can reduce the risk of a successful exploit and protect their Citrix Virtual Apps and Desktops environment.

Timeline

Published on: 07/10/2023 21:15:00 UTC
Last modified on: 07/18/2023 17:33:00 UTC