# Exposing the Risks of Open Ollama APIs

> How the Ollama API service can end up reachable from the internet and the practical steps that close it off.

- Author: Vibhek Soni (https://vibheksoni.com/)
- Published: 2026-01-23
- Tags: api security, ollama, network security
- URL: https://opendoors.wtf/blog/ollama-api-security/

## The Problem

Ollama is a popular API service that runs locally on your machine so you can use AI models without external cloud infrastructure. It operates on port **11434** and is accessible via `http://localhost:11434`.

The issue is that Ollama has no built-in authentication. That is not a vulnerability on its own but it becomes one the moment the port is reachable from the internet. Anyone who finds it can use your models and your hardware without asking.

## What Can Go Wrong

Without authentication and with an open port, an attacker could:

- Interact with your AI models
- Download models running on your machine
- Execute tasks using your hardware resources

If you run Ollama on a rented GPU box the bill still arrives whether or not you used it. Somebody else did.

## How I Found This

The `ollama serve` command tells you the service is already running as soon as Ollama is installed and active. So I checked the scale of this exposure with **FOFA** which is a cyberspace search engine.

I searched for machines exposing port 11434 with the query `"Ollama is running" && port="11434"`. That signature works because the root endpoint of a default Ollama install returns exactly that string so it is a reliable way to find live instances.

[Image: FOFA.info search query showing port 11434 search]

The search returned **65,766 exposed hosts**.

[Image: FOFA.info search results displaying 65,766 exposed Ollama instances]

- Open port 11434 was reachable on every one of them
- I could read models and send requests to their GPUs
- Many were on expensive hardware and the owner had no idea

## How to Protect Your Ollama Service

If you use Ollama, take these steps to secure your service:

### 1. IP Whitelisting

Use a firewall and allow only the IPs you trust.

### 2. Add an Authentication Wrapper

Put a proxy in front of it that asks for a token before it forwards anything.

### 3. Disable Public Port Access

Bind it to `127.0.0.1` so the port is not reachable from outside the machine.

## Conclusion

This is not about blaming Ollama. It ships a local service and that is the correct default. The problem starts when a local service ends up on a public IP and nobody checked. Twenty minutes with a firewall is the whole fix.