Journyx Unauthenticated Password Reset Bruteforce

Vulnerability Description

Password reset tokens are generated using an insecure source of randomness. Attackers who know the username of the Journyx installation user can bruteforce the password reset and change the administrator password.

Technical Description

From an unauthenticated perspective, a user can initiate the
password reset flow by clicking the "Reset your password" button
on the Journyx login screen and supplying a valid username. A
password reset link containing a "random" token is sent to the
email address associated with the username.

The password reset token is generated using the current epoch
and the user ID associated with the request. The user ID is
a 128-bit UUID for every user *except* for the user created
during the initial setup of the Journyx instance, i.e., the
system administrator account. For this single user, the user
ID defaults to the username. By targeting this user, the need
to leak a UUID is removed entirely. If the Journyx instance was
configured according to the official System Administration guide
(https://journyx.com/Files/Journyx_Sysadmin_and_Recovery_v11.pdf),
the username is "journyx". Alternatively, the username can be
leaked via stacktraces.

When generating the token, a secret key is created by inserting
the user ID in between the strings 'chuck' and 'palahniuk':

   mysessiontoken = 'chuck%spalahniuk' % me

This key is used to XOR the string literal representation of
the list object `[userID, time.time()]`. The output of the XOR
function is then base64 encoded:

   eStr = xor_str(istr, key)
   aStr = binascii.b2a_base64(eStr).strip()

Since the user ID is a known value, only the output of
`time.time()` (the epoch at the time of "encryption") is
unknown. However, by opening a TCP connection and noting the
epoch immediately after sending an HTTP request to initiate
the password reset flow, a pool of tokens can be generated by
incrementing the epoch. There is a high degree of certainty
the valid reset token is contained within a pool larger than
50,000 tokens.

Depending upon network latency and other external factors,
a successful bruteforce attack using these tokens can take
anywhere from several minutes to over an hour.

Mitigation and Remediation Recommendation

The vendor reports that this issue was remediated in Journyx v12.0.0, which is the first wholly cloud-hosted version of this product.

For self-hosted versions of Journyx, one incremental improvement is to disable user-initiated password reset functionality in the application settings.

1. Log into the JournyX web application as an administrator
2. Navigate to Configuration -> System Settings -> Security Settings
3. Ensure the checkbox labeled “Show a password reset button on login screen” is disabled.
4. Click the “Save” button

Another option would be to monkey patch the .pyc file that contains these hardcoded strings, ./wtdoc.pyc, by deploying a .py file that uses unique strings and then loads wtdoc_original.pyc (see KL-001-2024-008 and KL-001-2024-009 for examples).

Credit

This vulnerability was discovered by Jaggar Henry of KoreLogic, Inc.

Proof of Concept

The following script automatically exploits this issue by initiating
a password reset flow and bruteforces the value after generating a
list of 50,000 tokens.

    [attacker@box]$ python unauth2rce.py --url http://redacted.com:8080/ --username foo --command id
    [*] Beginning Attack. Using the following timestamp: "1706708084.2051988"
    [+] New Password Generated: 2DCD5AE1F0F34B84A1E0F1FB5768219B

The contents of this advisory are copyright(c) 2024 KoreLogic, Inc. and are licensed under a Creative Commons Attribution Share-Alike 4.0 (United States) License: http://creativecommons.org/licenses/by-sa/4.0/

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