CVE-2025-57955

Executive Summary

CVE-2025-57955 is a Missing Authorization vulnerability in the WordPress plugin Post Carousel Slider for Elementor, developed by Plugin Devs. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access or modification. The vulnerability affects all versions up to and including 1.7.0. As of this report, no official patch has been released, and no public proof-of-concept (PoC) code is available. The CVSS score is 6.5 (Medium), indicating a moderate risk primarily due to the lack of authentication required for exploitation.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin ecosystem. WordPress plugins are distributed via the official WordPress Plugin Directory or third-party marketplaces. The absence of a patch means that all installations of this plugin are currently at risk. Users should monitor the plugin's update channel for a security fix and consider disabling the plugin until a patch is available.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
• Base Score: 6.5 (Medium)
• Attack Vector: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No user action required.
• Scope: Unchanged (S:U) – Impact confined to the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited data exposure.
• Integrity Impact: Low (I:L) – Limited data modification.
• Availability Impact: None (A:N) – No denial of service.

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low confidentiality and integrity loss.

Deep Dive & Mechanics

The vulnerability stems from a Missing Authorization check (CWE-862) in the plugin's AJAX handlers or REST API endpoints. The plugin likely exposes functions that perform actions such as retrieving or modifying slider data without verifying that the requesting user has the necessary permissions (e.g., edit_posts capability). An unauthenticated attacker can send crafted HTTP requests to these endpoints to:

• Read sensitive slider configurations or post data.
• Modify slider settings, potentially injecting malicious content or redirecting users.

The core issue is that the plugin relies on incorrect access control security levels, meaning it may check for a capability that is too broad or not check at all. For example, it might use current_user_can('read') instead of current_user_can('edit_posts'), allowing any logged-in user (or even unauthenticated users if the check is missing) to perform privileged actions.

Vulnerable vs. Patched Code

Since no patch is available, we can only hypothesize the vulnerable code pattern. The vulnerable version likely contains code similar to:

// Vulnerable: No capability check
add_action('wp_ajax_nopriv_carousel_slider_update', 'carousel_slider_update_handler');
function carousel_slider_update_handler() {
    // Process request without checking user permissions
    update_option('carousel_slider_data', $_POST['data']);
}

A patched version would include a proper capability check:

// Patched: Check user capability
add_action('wp_ajax_carousel_slider_update', 'carousel_slider_update_handler');
function carousel_slider_update_handler() {
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized', 403);
    }
    // Process request
    update_option('carousel_slider_data', $_POST['data']);
}

Note the change from wp_ajax_nopriv_ (allows unauthenticated access) to wp_ajax_ (requires authentication) and the addition of current_user_can().

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with the vulnerable plugin installed (version <= 1.7.0).
• Network access to the site.

Exploitation Steps:

1. Identify Vulnerable Endpoints: Use a tool like Burp Suite or curl to probe for AJAX actions. Common patterns include admin-ajax.php?action=carousel_slider_*.

2. Craft Exploit Request: Send a POST request to the vulnerable endpoint without authentication.

curl -X POST http://target.com/wp-admin/admin-ajax.php \
  -d "action=carousel_slider_update&data=malicious_payload"

3. Verify Exploitation: Check if the slider data has been modified or if sensitive information is returned in the response.

Note: No public PoC exists, so this is a theoretical approach based on the vulnerability description.

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with actions related to the plugin (e.g., carousel_slider_*).
• Look for requests from unauthenticated users to wp-admin/admin-ajax.php that result in 200 OK responses (indicating successful exploitation).

Hardening:

• Disable the plugin immediately if not essential.
• Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with suspicious actions.
• Restrict access to wp-admin/ directory via .htaccess or IP whitelisting.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP POST requests to /wp-admin/admin-ajax.php with parameter action=carousel_slider_* from unauthenticated sources.
  • Unusual response sizes or content from admin-ajax.php indicating data exfiltration.

• File IOCs:

  • Modified options in the wp_options table (e.g., carousel_slider_data).
  • Unexpected files in the uploads directory if the plugin allows file uploads.

• Log IOCs:

  • WordPress debug log entries showing wp_ajax_nopriv_* actions being called.
  • Web server access logs with repeated requests to admin-ajax.php with the vulnerable action.

Detection Engineering

YARA Rule

rule Detect_Vulnerable_Post_Carousel_Slider {
    meta:
        description = "Detects vulnerable version of Post Carousel Slider for Elementor plugin"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-57955"
    strings:
        $vuln_func = "wp_ajax_nopriv_carousel_slider" nocase
        $version = "Version: 1.7.0" nocase
    condition:
        $vuln_func or $version
}

Sigma Rule

title: Detect Exploitation of CVE-2025-57955
id: 8a4b3c2d-1e5f-6a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated AJAX requests to vulnerable Post Carousel Slider for Elementor plugin
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=carousel_slider_'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin actions (if authenticated)
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-57955 - Post Carousel Slider for Elementor Missing Authorization";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"admin-ajax.php"; http_uri;
    content:"action=carousel_slider_"; http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
    priority:2;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Plugin: Deactivate and delete the Post Carousel Slider for Elementor plugin until a patch is released.
2. Monitor Logs: Review web server and WordPress logs for signs of exploitation.
3. Apply Virtual Patching: Use a WAF to block requests to admin-ajax.php with actions starting with carousel_slider_ from unauthenticated users.

Long-Term Fix:

• The vendor must release a patched version that adds proper capability checks (e.g., current_user_can('edit_posts')) to all AJAX handlers.
• Users should update to the latest version once available.

Workaround:

• If the plugin is critical, consider implementing a custom function in the theme's functions.php to add capability checks:

add_action('init', function() {
    if (isset($_POST['action']) && strpos($_POST['action'], 'carousel_slider_') === 0) {
        if (!current_user_can('edit_posts')) {
            wp_die('Unauthorized', 403);
        }
    }
});

Valters IT
Securing Digital Frontiers