Web server fingerprint

It was only a matter of time until the first queries for tools like https://www.shodan.io to search for Home Assistant instances showed up.

To get an idea about how your Home Assistant instance looks to a network scanner, you can use nmap. The nmap tool is already available if you are using the nmap device tracker.

$ nmap -sV -p 8123 --script=http-title,http-headers

Starting Nmap 7.60 ( https://nmap.org ) at 2018-05-29 18:16 CEST
Nmap scan report for
Host is up (0.0058s latency).

8123/tcp open  http    aiohttp 3.1.3 (Python 3.6)
| http-headers: 
|   Content-Type: text/html; charset=utf-8
|   Content-Length: 3073
|   Date: Tue, 29 May 2018 16:16:50 GMT
|   Server: Python/3.6 aiohttp/3.1.3
|   Connection: close
|_  (Request type: GET)
|_http-server-header: Python/3.6 aiohttp/3.1.3
|_http-title: Home Assistant

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 12.13 seconds

We don’t have an unique server banner but in combination with the HTML title Home Assistant, is it simple to identify Home Assistant instances.

$ nc 8123
GET / HTTP/1.1
host: localhost

HTTP/1.1 200 OK
Server: Python/3.6 aiohttp/3.1.3

One option to avoid this exposure is using a reverse proxy.