CVE-2024-4997

Executive Summary

CVE-2024-4997 is a vulnerability in the WPUpper Share Buttons WordPress plugin (versions up to and including 3.43). The flaw allows unauthenticated attackers to bypass access controls and retrieve the contents of password-protected posts and pages. This is achieved by exploiting the plugin's mechanism for preparing sharing links, which fails to properly enforce the password protection check. The vulnerability has a CVSS score of 5.3 (Medium), with a low EPSS score of 0.0% indicating no active exploitation in the wild at the time of analysis. No public proof-of-concept (PoC) or exploit code has been released. The patch status is unknown, and no official update has been confirmed by the vendor.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed through the official WordPress plugin repository. Users are advised to monitor the plugin's page for updates and consider disabling the plugin if it is not critical to operations.

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: 5.3 (Medium)
• Attack Vector: Network (AV:N) – The vulnerability can be exploited remotely.
• Attack Complexity: Low (AC:L) – No special conditions are required.
• Privileges Required: None (PR:N) – No authentication is needed.
• User Interaction: None (UI:N) – No user action is required.
• Scope: Unchanged (S:U) – The impact is confined to the vulnerable component.
• Confidentiality Impact: Low (C:L) – Only the content of password-protected posts is exposed.
• Integrity Impact: None (I:N) – No data modification is possible.
• Availability Impact: None (A:N) – No denial of service.

Threat Level: Medium. The vulnerability is easy to exploit but has limited impact (information disclosure only). No active exploitation has been observed.

Deep Dive & Mechanics

The WPUpper Share Buttons plugin generates sharing links for social media platforms. When processing a request to create a share link for a post or page, the plugin retrieves the post content without first verifying if the post is password-protected. The vulnerable code likely uses a function like get_post() or setup_postdata() without checking the post_password field. An unauthenticated attacker can craft a request (e.g., via a direct HTTP GET to the plugin's AJAX endpoint) that triggers the share link generation for a protected post, causing the plugin to return the post's content in the response.

The vulnerability is present in all versions up to and including 3.43. The exact vulnerable function is not publicly documented, but it is likely in the plugin's main PHP file (e.g., wpupper-share-buttons.php) or an AJAX handler.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on the vulnerability description.

Vulnerable Code (Conceptual):

// In the plugin's AJAX handler
function wpusb_get_share_content() {
    $post_id = $_GET['post_id'];
    $post = get_post($post_id);
    // No check for password protection
    $content = $post->post_content;
    echo json_encode(array('content' => $content));
    wp_die();
}

Patched Code (Conceptual):

function wpusb_get_share_content() {
    $post_id = $_GET['post_id'];
    $post = get_post($post_id);
    // Check if post is password protected and password not provided
    if (post_password_required($post)) {
        wp_die('Access denied', 403);
    }
    $content = $post->post_content;
    echo json_encode(array('content' => $content));
    wp_die();
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with the WPUpper Share Buttons plugin (version <= 3.43) installed and active.
• At least one password-protected post or page.

Exploitation Steps:

1. Identify the AJAX endpoint used by the plugin. This is typically /wp-admin/admin-ajax.php with an action parameter.
2. Determine the action name (e.g., wpusb_get_share_content or similar). This can be found by inspecting the plugin's JavaScript or source code.
3. Craft a GET request to the endpoint with the ID of a password-protected post:

   GET /wp-admin/admin-ajax.php?action=wpusb_get_share_content&post_id=123 HTTP/1.1
   Host: target-wordpress-site.com
   

4. The response will contain the full content of the password-protected post in JSON format.

Example cURL command:

curl -v "http://target-wordpress-site.com/wp-admin/admin-ajax.php?action=wpusb_get_share_content&post_id=123"

Expected Output:

{"content":"This is the protected content of the post."}

Blue Team (Detection & Prevention)

Detection:

• Monitor for unusual requests to /wp-admin/admin-ajax.php with parameters like action=wpusb_get_share_content and post_id.
• Look for requests that do not include a valid nonce or session cookie (indicating unauthenticated access).
• Check server logs for 200 responses to such requests that contain post content in the response body.

Prevention:

• Disable the plugin until a patch is released.
• Implement a Web Application Firewall (WAF) rule to block requests to the vulnerable AJAX action from unauthenticated users.
• Use a security plugin like Wordfence to add virtual patching.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /wp-admin/admin-ajax.php with action=wpusb_get_share_content (or similar) and a post_id parameter.
  • Response bodies containing JSON with a content key that includes post content.
• File IOCs:
  • Plugin file: /wp-content/plugins/wpupper-share-buttons/wpupper-share-buttons.php (or similar).
  • Version string in plugin header: Version: 3.43 or lower.
• Log IOCs:
  • Apache/Nginx access logs showing requests to admin-ajax.php with the vulnerable action from IPs not associated with authenticated users.

Detection Engineering

YARA Rule

rule CVE_2024_4997_WPUpper_Share_Buttons {
    meta:
        description = "Detects exploitation attempts of CVE-2024-4997 in WPUpper Share Buttons plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-4997"
    strings:
        $ajax_action = "wpusb_get_share_content" nocase
        $post_id_param = "post_id=" nocase
        $json_content = "\"content\":" nocase
    condition:
        all of them
}

Sigma Rule

title: CVE-2024-4997 WPUpper Share Buttons Unauthorized Data Access
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects unauthenticated requests to the WPUpper Share Buttons AJAX endpoint that may indicate exploitation of CVE-2024-4997.
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'GET'
        c-uri|contains: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains|all:
            - 'action=wpusb_get_share_content'
            - 'post_id='
    condition: selection
falsepositives:
    - Legitimate use by authenticated users (if the plugin is used normally)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-4997 WPUpper Share Buttons Unauthorized Data Access"; flow:to_server,established; content:"GET"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=wpusb_get_share_content"; http_uri; content:"post_id="; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if it is not essential for business operations.
2. Apply virtual patching using a WAF to block unauthenticated requests to the vulnerable AJAX endpoint.
3. Monitor logs for any signs of exploitation.

Long-term Fix:

• Wait for the vendor (Wpupper) to release a patched version. Check the WordPress plugin repository for updates.
• If the plugin is no longer maintained, consider replacing it with an alternative sharing plugin that is actively supported.

Workaround:

• If the plugin must remain active, restrict access to admin-ajax.php using .htaccess rules or a security plugin to only allow authenticated requests for the vulnerable action.

Valters IT