---
title: "NET-APP-001 Debugger or Application Control Ports Exposed"
canonical: https://openvapt.com/checks/NET-APP-001.html
html: https://openvapt.com/checks/NET-APP-001.html
site: OpenVAPT, https://openvapt.com/
license: OpenVAPT Source-Available Licence 1.3, https://openvapt.com/legal/licence-text.html
modified: 2026-10-16
version: 0.1.0-alpha.6
---

# NET-APP-001 Debugger or Application Control Ports Exposed

Checks whether the Node.js inspector, Tomcat AJP or shutdown port, PHP-FPM FastCGI or Jupyter listen on network-reachable addresses.

- Domain: Network
- Severity: High
- Control category: Network Exposure
- Fix effort: low
- CVSS v3.1 vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L`
- CIS Controls v8: 4.8
- NIST CSF 2.0: PR.PS-01, PR.IR-01
- CWE: CWE-489, CWE-1327
- OWASP Top 10 2021: A05:2021
- NIST SP 800-53 Rev. 5: SC-7, CM-7
- Benchmark topic: Expose applications only through a hardened front end (topic only, no benchmark text)

## Why It Matters

These ports are not web pages: the Node.js inspector and Jupyter run code for whoever connects, Tomcat AJP has been abused for file read and code execution (Ghostcat), the shutdown port stops the server, and PHP-FPM executes scripts handed to it. None of them is designed to face a network.

## How It Detects

Matches network-reachable listening TCP sockets from /proc/net against the default ports of these debuggers and control protocols, recording how each is bound. Plain application HTTP ports are rated separately by NET-APP-002. No packets are sent.

## How to Fix

Bind each to 127.0.0.1 or a Unix socket (node --inspect=127.0.0.1:9229; Tomcat Connector address="127.0.0.1" or remove the AJP connector; PHP-FPM listen = /run/php/php-fpm.sock; jupyter --ip=127.0.0.1) and never expose a debugger.

## How to Verify

```
ss -tlnp  shows these ports on 127.0.0.1 or ::1 only.
```

## Learn the Theory

- [P13 Application Servers: Tomcat, Node.js and Python](https://openvapt.com/academy/p13.md)

## References

- [Node.js, Inspector security implications](https://nodejs.org/en/learn/getting-started/debugging#security-implications)
- [Apache Tomcat 9, AJP Connector](https://tomcat.apache.org/tomcat-9.0-doc/config/ajp.html)

## Source Code

https://github.com/OpenVAPT/openvapt/blob/574f7f3333c44b75a3c649e2d93a76d507f75adf/internal/checks/network/firewall_exposure.go

Run it: `openvapt scan --only NET-APP-001`. Read it offline: `openvapt explain NET-APP-001`.

---

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