CVE-2024-48896 - A Critical Vulnerability Uncovered in Moodle Allowing Unauthorized User Information Access Via Messaging System

A serious security concern, labeled as CVE-2024-48896, has recently been discovered in the Moodle learning management system. The vulnerability allows users with the "send message" capability to exploit an error message in the Messaging system and consequently access other users' full names, even if they were not supposed to have access to this information. As full names can be sensitive information and could lead to various privacy infringements and other malicious actions, this vulnerability has to be taken seriously and proper mitigation techniques should be employed.

Vulnerability Details

In order to exploit the vulnerability, a user with "send message" capability can send a crafted message to the target user in Moodle's messaging system. Due to a bug in the code handling messaging errors, an error message is generated that may include the full name of the recipient.

Here's a code snippet showcasing the vulnerability

<?php
/* Example vulnerable code in messaging system */

// ...[Other code]...

$data = new stdClass();
$data->useridto = $userid; //intended recipient user ID
$data->useridfrom = $sender; //sender user ID
$data->subject = 'Sample Message';
$data->message = 'Hello, this is a test message';

//Extract user's full name based on configurations
$fullname = get_full_name($site, $userid);

// ...[Other code]...

function get_full_name($site, $userid) {
    /*
    This function generates a user's full name based on configured formats on a given site
    */

    // ...[Other code]...

    $fullname = generate_full_name_based_on_config($nameconfig, $userdata);
    return $fullname;
}

// ...[Other code]...

if (send_message($data)) {
    echo 'Message sent successfully';
} else {
    //ERROR, the full name is returned in error
    echo 'There was an error sending your message to ' . $fullname;
}

// ...[Other code]...

?>

The name returned in the error message aligns with the site-wide full name format configuration.

The original references and exploit details can be found here

- Moodle Tracker Issue
- Security Advisory
- CVE Details

Impact and Exploitability

This vulnerability could allow an attacker to access sensitive user information, such as full names, that they should not have access to. Unscrupulous individuals and entities could exploit this information for a range of harmful purposes, such as stalking, harassment, identity theft, and targeted phishing attacks.

The fact that exploitation only requires "send message" capability means that a large number of users can potentially exploit the vulnerability, making it even more dangerous.

Recommendations

As a Moodle administrator, it is essential to take immediate action to mitigate the impact of CVE-2024-48896. The following steps should be taken:
1. Upgrade to the most recent Moodle version, which addresses the vulnerability. The versions that include the fix are: {insert_specific_versions_with_fix_here}.
2. If an upgrade is not feasible right away, restrict the "send message" capability to trusted users only.
3. Inform your users of the vulnerability and advise them to be cautious and aware of potential malicious activity and phishing attempts.

Conclusion

The discovery of CVE-2024-48896 stresses the importance of staying informed and taking action to protect your Moodle installation from security vulnerabilities. Staying aware of emerging issues, promptly applying security patches, and maintaining open communication with your users will go a long way towards keeping your e-learning environment safe and secure.

Timeline

Published on: 11/18/2024 12:15:18 UTC
Last modified on: 11/20/2024 14:47:12 UTC