CVE-2014-7836: Moodle multiple cross-site request forgery (CSRF) vulnerabilities

Background

Moodle is an open-source learning management system (LMS) used by educational institutions to create and manage online courses. It provides a platform for educators to deliver content, interact with students, and assess their progress. The LTI module in Moodle allows integration with external tools and services. However, versions prior to 2.5.9, 2.6.6, and 2.7.3 are vulnerable to multiple cross-site request forgery (CSRF) attacks.

Vulnerability Detail

The identified vulnerabilities in Moodle's LTI module allow remote attackers to hijack the authentication of arbitrary users. By exploiting these vulnerabilities, an attacker can perform unauthorized actions on behalf of the targeted user. The vulnerabilities exist in the 'mod/lti/request_tool.php' and 'mod/lti/instructor_edit_tool_type.php' endpoints. These endpoints do not properly validate the authenticity of requests, making it possible for an attacker to forge requests and trick users into unknowingly performing malicious actions.

Workaround

If an immediate update is not possible, administrators can implement a workaround by applying custom code changes to the affected endpoints. The code changes should include proper request validation and verification mechanisms to prevent CSRF attacks. Here is an example of how the 'mod/lti/request_tool.php' endpoint can be secured:

// Add the following code at the beginning of the 'request_tool.php' file

// Verify the authenticity of the request
if ($_SERVER['REQUEST_METHOD'] !== 'POST' || empty($_POST['csrf_token']) || $_POST['csrf_token'] !== $_SESSION['csrf_token']) {
    // Invalid or missing CSRF token, reject the request
    header('HTTP/1.1 403 Forbidden');
    exit;
}

// Rest of the original code
// ...

Note: This is a simplified example and may require additional modifications based on the Moodle version and specific implementation.

Conclusion

The identified vulnerabilities in Moodle's LTI module pose a risk of unauthorized actions being performed on behalf of users. It is crucial for administrators to update Moodle to versions 2.5.9, 2.6.6, or 2.7.3, depending on the installed version, to mitigate the risk of CSRF attacks. Additionally, implementing proper request validation and verification mechanisms can provide an interim solution until the update is applied. For further support on vulnerability remediation, please contact DevNack.com.

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