CVE-2025-11004

Executive Summary

CVE-2025-11004 is a Reflected Cross-Site Scripting (XSS) vulnerability in the Simplicity Device Manager Tool. The flaw exists in several API endpoints, allowing an attacker on the same network to inject malicious scripts. Successful exploitation can compromise the confidentiality, integrity, and availability of the system running the tool. No patch is currently available, and no public proof-of-concept (PoC) code has been released. The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation). The attack vector is network-adjacent, requiring the attacker to be on the same local network as the target.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is likely a placeholder or uncalculated. Based on the description, a reasonable CVSS v3.1 vector would be: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L (Score: 5.4, Medium). This reflects the network adjacency requirement, low attack complexity, no privileges required, user interaction needed, and a scope change with low impacts to confidentiality, integrity, and availability.

Deep Dive & Mechanics

The Simplicity Device Manager Tool exposes several API endpoints that do not properly sanitize user-supplied input. When a victim user accesses a crafted URL containing malicious JavaScript, the script is reflected back in the HTTP response and executed in the victim's browser context. Because the attacker must be on the same network, this is a local network attack, often used in conjunction with ARP spoofing or DNS poisoning to redirect the victim to the malicious URL. The vulnerability affects the tool's web interface, which is typically used for device management and monitoring.

Vulnerable vs. Patched Code

No patch is available. The vulnerable code likely lacks output encoding or input validation in API endpoints that return user-controlled parameters. A patched version would implement proper HTML entity encoding (e.g., using htmlspecialchars() in PHP or equivalent in other languages) and validate input against a whitelist of allowed characters.

Exploitation & Lab Setup

Red Team

Since no public exploit code exists, a manual exploitation approach is required. The attacker crafts a URL such as:

http://<target-ip>:<port>/api/endpoint?param=<script>alert('XSS')</script>

The attacker then lures a victim on the same network to click the link (e.g., via a phishing email or by injecting the link into a legitimate page). The script executes in the victim's browser, potentially stealing session cookies or performing actions on behalf of the victim.

Lab Setup:

1. Install Simplicity Device Manager Tool on a local VM (e.g., Windows Server 2019).
2. Ensure the tool's web interface is accessible on the local network.
3. Use a second VM (attacker) on the same subnet.
4. Use a browser or curl to test reflected XSS:

   curl "http://<target-ip>:<port>/api/endpoint?param=<script>alert('XSS')</script>"
   

5. Observe if the script is reflected in the response.

Blue Team

• Monitor web server logs for unusual query parameters containing <script>, onerror, javascript:, or other XSS payloads.
• Implement a Web Application Firewall (WAF) rule to block requests with suspicious patterns.
• Restrict access to the Simplicity Device Manager interface to trusted IP addresses only.
• Use network segmentation to isolate the tool from untrusted hosts.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /api/ endpoints containing <script> tags or alert() functions.
  • Unusual referrer headers from internal IPs.
• Host IOCs:
  • Web server logs showing repeated requests with encoded XSS payloads.
  • Browser history or cache entries containing malicious URLs.
• File IOCs:
  • No specific file hashes; the vulnerability is in the application logic.

Detection Engineering

YARA Rule

rule CVE_2025_11004_Reflected_XSS {
    meta:
        description = "Detects reflected XSS attempts against Simplicity Device Manager API endpoints"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-11004"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/i
        $api_endpoint = /\/api\/([a-zA-Z0-9_]+)\?/
    condition:
        $api_endpoint and $xss_payload
}

Sigma Rule

title: Reflected XSS Attempt Against Simplicity Device Manager
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects HTTP requests to Simplicity Device Manager API endpoints containing XSS payloads
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains:
            - '<script>'
            - 'alert('
            - 'onerror='
            - 'javascript:'
        cs-uri-stem|startswith: '/api/'
    condition: selection
falsepositives:
    - Legitimate use of script tags in API parameters (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-11004 Reflected XSS in Simplicity Device Manager API";
    flow:to_server,established;
    content:"/api/"; http_uri;
    pcre:"/<script[^>]*>.*?<\/script>/i";
    classtype:web-application-attack;
    sid:10000001;
    rev:1;
)

Remediation & Mitigation

• Immediate: Restrict network access to the Simplicity Device Manager interface using firewall rules. Only allow trusted IPs.
• Short-term: Implement a Web Application Firewall (WAF) to block XSS payloads. Use input validation and output encoding in any custom scripts interacting with the API.
• Long-term: Contact the vendor Simplicity for a patch. If no patch is forthcoming, consider replacing the tool with an alternative that is actively maintained.
• Compensating Controls: Use network segmentation to isolate the tool from user workstations. Enable HTTP-only cookies to mitigate session theft.

Valters IT