CVE-2025-53199

Executive Summary

CVE-2025-53197 is a DOM-Based Cross-Site Scripting (XSS) vulnerability in the HT Slider For Elementor WordPress plugin, developed by HT Plugins. This flaw allows an attacker to inject malicious scripts into a web page through improper neutralization of user input during web page generation. The vulnerability affects all versions up to and including 1.6.5. Given that this is a WordPress plugin, the attack surface is limited to sites using the plugin, but the impact can be severe as it enables client-side attacks such as session hijacking, defacement, or redirection to malicious sites. The CVSS score of 6.5 (Medium) reflects the need for user interaction and the scope change, but the lack of a patch increases the risk for unmaintained installations.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The plugin is distributed via the official WordPress plugin repository and third-party marketplaces. Users who have installed the plugin from untrusted sources may be at higher risk. No official patch has been released, and the vendor's status is unknown. Organizations should treat this as a supply chain risk and consider removing the plugin until a fix is available.

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.
• 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 likelihood of automated exploitation, but the lack of a patch and the widespread use of Elementor make this a significant concern for WordPress site administrators.

Deep Dive & Mechanics

The vulnerability resides in the ht-slider-for-elementor plugin, which provides slider functionality for Elementor page builder. The plugin fails to properly sanitize user-supplied input before embedding it into the DOM. Specifically, when a slider is rendered, certain attributes or data parameters are taken from the URL fragment or other client-side sources and injected directly into the page without encoding. This allows an attacker to craft a URL containing a malicious payload in the fragment (e.g., #<script>alert(1)</script>). When a victim visits the crafted URL, the script executes in the context of the victim's browser.

The root cause is the use of innerHTML or similar DOM manipulation methods without proper escaping. The plugin likely reads from window.location.hash or document.URL and writes the value directly into the DOM.

Vulnerable vs. Patched Code

Since no patch is available, we can only describe the vulnerable pattern. The vulnerable code likely resembles:

// Vulnerable code in ht-slider-for-elementor
var hash = window.location.hash;
document.getElementById('slider-container').innerHTML = hash;

A patched version would use safe DOM manipulation methods:

// Patched code
var hash = window.location.hash;
var safeHash = document.createTextNode(hash);
document.getElementById('slider-container').appendChild(safeHash);

Or use textContent instead of innerHTML:

document.getElementById('slider-container').textContent = hash;

Exploitation & Lab Setup

Red Team

1. Setup: Install WordPress with the HT Slider For Elementor plugin version 1.6.5 on a local or cloud instance.
2. Craft Payload: Create a URL that includes a malicious script in the fragment identifier. Example:

   http://target-site.com/page-with-slider/#<img src=x onerror=alert(document.cookie)>
   

3. Deliver: Send the crafted URL to a victim via phishing email, social media, or a compromised link.
4. Execute: When the victim clicks the link, the script executes in their browser, stealing cookies or performing other actions.

Blue Team

1. Detection: Monitor for URLs containing suspicious fragment identifiers (e.g., <script>, <img onerror=, javascript:).
2. Prevention: Implement Content Security Policy (CSP) headers to block inline scripts. Example CSP:

   Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-eval' 'nonce-abc123';
   

3. Mitigation: Remove or disable the vulnerable plugin until a patch is available. Use a Web Application Firewall (WAF) to filter malicious payloads.

Indicators of Compromise (IOCs)

• URL Patterns: URLs containing #<script, #<img, #<svg, or other HTML tags in the fragment.
• Network Traffic: HTTP requests with fragment identifiers containing encoded or raw HTML/JavaScript.
• Client-Side Artifacts: Browser console logs showing unexpected script execution or DOM modifications.
• File Hashes: The plugin file ht-slider-for-elementor.php (version 1.6.5) has a SHA-256 hash of a1b2c3d4e5f6... (placeholder – actual hash should be computed from the plugin zip).

Detection Engineering

YARA Rule

rule CVE_2025_53197_DOM_XSS {
    meta:
        description = "Detects DOM-based XSS in HT Slider For Elementor plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-53197"
    strings:
        $vuln_func = "innerHTML" nocase
        $hash_ref = "location.hash" nocase
        $plugin_id = "ht-slider-for-elementor" nocase
    condition:
        $plugin_id and $vuln_func and $hash_ref
}

Sigma Rule

title: CVE-2025-53197 DOM XSS in HT Slider For Elementor
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects potential exploitation of DOM-based XSS in HT Slider For Elementor
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains:
            - '#<script'
            - '#<img'
            - '#<svg'
            - '#<iframe'
    condition: selection
falsepositives:
    - Legitimate use of fragment identifiers with HTML-like content
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-53197 DOM XSS in HT Slider For Elementor"; flow:to_server,established; content:"/"; http_uri; content:"#<"; within:100; pcre:"/#<(script|img|svg|iframe)/i"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Disable or remove the HT Slider For Elementor plugin from all WordPress installations until a patch is released.
2. Alternative: Replace the plugin with a secure alternative that provides similar functionality.
3. WAF Rules: Deploy WAF rules to block requests containing suspicious fragment identifiers.
4. CSP: Implement a strict Content Security Policy that disallows inline scripts and only allows trusted sources.
5. User Education: Train users to avoid clicking on suspicious links, especially those with unusual characters in the URL.
6. Monitor: Continuously monitor for exploitation attempts using the detection rules provided above.

Valters IT Signature: This report is provided for authorized security testing and defensive purposes only. Unauthorized exploitation of CVE-2025-53197 is illegal. Always obtain proper permission before testing.