CVE-2024-1769

Executive Summary

CVE-2024-1769 is an information exposure vulnerability in the JM Twitter Cards plugin for WordPress, affecting all versions up to and including version 14. The flaw allows unauthenticated attackers to view the content of password-protected posts by inspecting the page source. The vulnerability resides in how the plugin handles meta description data, inadvertently exposing the protected content in the HTML source. This is a WordPress ecosystem issue, not related to the underlying web server.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. No supply chain compromise is indicated, but the lack of a patch increases risk for sites using this plugin.

CVSS Breakdown & Threat Level

• CVSS Score: 5.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low (exposure of password-protected post content)
• Integrity Impact: None
• Availability Impact: None

The threat level is medium due to the low complexity and no authentication requirement, but the impact is limited to information disclosure.

Deep Dive & Mechanics

The JM Twitter Cards plugin generates meta tags for Twitter card integration. In vulnerable versions, when a password-protected post is rendered, the plugin incorrectly includes the post content in the meta description tag. This occurs because the plugin does not check the post's password protection status before extracting content for the meta description.

Root Cause: The plugin uses get_the_excerpt() or similar functions without verifying if the post is password-protected. When the post content is protected, the excerpt should be empty or show a "protected" message, but the plugin bypasses this check.

Attack Vector: An unauthenticated attacker can:

1. Identify a WordPress site using the JM Twitter Cards plugin.
2. Navigate to a password-protected post.
3. View the page source (Ctrl+U or right-click > View Page Source).
4. Find the meta description tag containing the full post content.

Vulnerable vs. Patched Code

Vulnerable Code (version <= 14):

function jm_tc_meta_description() {
    global $post;
    $description = get_the_excerpt($post->ID);
    echo '<meta name="twitter:description" content="' . esc_attr($description) . '" />' . "\n";
}

Patched Code (hypothetical fix):

function jm_tc_meta_description() {
    global $post;
    if ( post_password_required($post->ID) ) {
        return; // Do not output meta description for protected posts
    }
    $description = get_the_excerpt($post->ID);
    echo '<meta name="twitter:description" content="' . esc_attr($description) . '" />' . "\n";
}

The fix adds a check for post_password_required() before outputting the meta description.

Exploitation & Lab Setup

Red Team

Prerequisites:

• WordPress site with JM Twitter Cards plugin (version <= 14)
• A password-protected post with content

Exploitation Steps:

1. Identify the target WordPress site.
2. Find a password-protected post (URL pattern: /password-protected-post/).
3. View the page source using browser developer tools or curl.
4. Search for twitter:description meta tag.

Example curl command:

curl -s http://target-site.com/password-protected-post/ | grep -oP '(?<=twitter:description" content=").*?(?=")'

Expected Output: The full content of the password-protected post.

Blue Team

Detection:

• Monitor for unusual access to password-protected posts without proper authentication.
• Check server logs for requests to password-protected posts followed by source code inspection.

Hunting:

• Search for twitter:description meta tags in page sources of password-protected posts.
• Use the following SQL query to identify vulnerable plugin versions:

SELECT option_value FROM wp_options WHERE option_name = 'active_plugins' AND option_value LIKE '%jm-twitter-cards%';

Indicators of Compromise (IOCs)

• File: /wp-content/plugins/jm-twitter-cards/jm-twitter-cards.php
• Plugin Version: <= 14
• Meta Tag in Source: <meta name="twitter:description" content="[protected content]">
• URL Pattern: Any password-protected post URL on a site with the vulnerable plugin

Detection Engineering

YARA Rule

rule CVE_2024_1769_JM_Twitter_Cards_Info_Leak {
    meta:
        description = "Detects JM Twitter Cards plugin vulnerable to information disclosure"
        author = "Valters IT"
        date = "2024-01-01"
        cve = "CVE-2024-1769"
    strings:
        $plugin_file = "jm-twitter-cards.php"
        $vuln_func = "get_the_excerpt"
        $meta_tag = "twitter:description"
    condition:
        $plugin_file and $vuln_func and $meta_tag
}

Sigma Rule

title: CVE-2024-1769 - JM Twitter Cards Information Disclosure
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects access to password-protected posts with exposed meta description
author: Valters IT
date: 2024/01/01
tags:
    - attack.t1592
    - cve.2024.1769
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-uri-query|contains: '/password-protected-post/'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate access by authorized users
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-1769 - JM Twitter Cards Info Leak Attempt"; flow:to_server,established; content:"twitter:description"; http_server_body; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the JM Twitter Cards plugin until a patch is available.
2. Remove the plugin entirely if not critical for operations.
3. Use a Web Application Firewall (WAF) to block requests containing twitter:description in password-protected post responses.

Long-term Fix:

• Apply the hypothetical patch shown in the "Vulnerable vs. Patched Code" section.
• Monitor the WordPress plugin repository for an official update.

Workaround:

• Add custom code to your theme's functions.php to filter the meta description:

add_filter('jm_tc_meta_description', function($description) {
    if (post_password_required()) {
        return '';
    }
    return $description;
});

Valters IT
Securing Digital Frontiers