CVE-2024-39645: Themeum Tutor LMS CSRF Vulnerability

CVE-2024-39645 Overview

CVE-2024-39645 is a Cross-Site Request Forgery (CSRF) vulnerability affecting Themeum Tutor LMS, a WordPress learning management system plugin. The flaw impacts all versions of Tutor LMS up to and including 2.7.2. An attacker can craft a malicious web page or link that, when visited by an authenticated user, triggers unauthorized state-changing requests against the target WordPress site. The vulnerability is tracked under CWE-352: Cross-Site Request Forgery.

Critical Impact
Successful exploitation requires user interaction but can lead to high impact on confidentiality, integrity, and availability of the affected WordPress installation.

Affected Products

Themeum Tutor LMS plugin for WordPress
All versions from initial release through 2.7.2
WordPress sites with the Tutor LMS plugin installed and active

Discovery Timeline

2024-08-26 - CVE-2024-39645 published to NVD
2024-09-18 - Last updated in NVD database

Technical Details for CVE-2024-39645

Vulnerability Analysis

The vulnerability stems from missing or improperly validated anti-CSRF protections in the Tutor LMS plugin. WordPress provides a nonce mechanism through wp_nonce_field() and check_admin_referer() that plugins must implement on state-changing endpoints. When these protections are absent or improperly checked, an attacker can forge requests that the browser submits on behalf of an authenticated victim.

The Network attack vector combined with required user interaction indicates the typical CSRF exploitation pattern. An attacker hosts a malicious page containing an auto-submitting form or fetch request targeting a Tutor LMS endpoint. When an authenticated administrator or instructor visits this page, the browser includes their session cookies with the forged request.

Root Cause

The root cause is the absence of sufficient request origin validation on sensitive Tutor LMS endpoints. Plugin actions that modify state, such as course settings, user roles, or instructor data, do not consistently verify a valid WordPress nonce tied to the requesting user session. This allows cross-origin requests to be processed as if they originated from a legitimate authenticated workflow.

Attack Vector

Exploitation requires an attacker to deliver a crafted link or web page to a logged-in WordPress user with sufficient privileges on a site running Tutor LMS 2.7.2 or earlier. Social engineering, phishing emails, or malicious advertisements typically serve as delivery mechanisms. Once the victim loads the attacker-controlled content, the forged request executes against the vulnerable endpoint with the victim's authenticated session.

The vulnerability mechanism is described in the Patchstack Vulnerability Report. No public proof-of-concept exploit is currently available.

Detection Methods for CVE-2024-39645

Indicators of Compromise

Unexpected modifications to Tutor LMS course content, settings, or user roles without corresponding administrator activity
HTTP Referer headers in WordPress access logs pointing to unknown external domains immediately preceding state-changing plugin requests
New or modified instructor accounts that administrators did not provision

Detection Strategies

Review WordPress access logs for POST requests to Tutor LMS endpoints originating from cross-origin referrers
Audit the WordPress activity log plugin output for administrative actions that lack a matching browser session
Compare current Tutor LMS configuration against known-good baselines to identify unauthorized changes

Monitoring Recommendations

Enable WordPress audit logging to capture all plugin configuration changes with timestamps and user attribution
Monitor outbound web traffic from administrator workstations for connections to suspicious domains that could host CSRF payloads
Alert on creation of new privileged users or modification of existing user capabilities in Tutor LMS

How to Mitigate CVE-2024-39645

Immediate Actions Required

Update Themeum Tutor LMS to a version later than 2.7.2 that contains the CSRF fix
Review all Tutor LMS instructor and administrator accounts for unauthorized changes or additions
Instruct privileged WordPress users to log out of administrative sessions when not actively managing the site

Patch Information

Themeum has addressed this issue in releases following Tutor LMS 2.7.2. Site administrators should consult the Patchstack Vulnerability Report for the specific patched version and upgrade through the WordPress plugin dashboard.

Workarounds

Restrict administrative access to the WordPress backend using IP allow-listing at the web server or firewall layer
Deploy a Web Application Firewall (WAF) with rules that validate the Origin and Referer headers on Tutor LMS endpoints
Require administrators to use a dedicated browser profile for WordPress management to reduce exposure to malicious cross-origin content

bash

# Example nginx configuration to enforce same-origin Referer on wp-admin
location ~ ^/wp-admin/admin-ajax\.php$ {
    if ($http_referer !~ "^https://yoursite\.example\.com/") {
        return 403;
    }
    include fastcgi_params;
    fastcgi_pass php-fpm;
}