I have a situation where multiple devices will be installed in public places and different maintenance engineers, from potentially different companies, will need to login via their wifi hotspot to set them up or monitor them (in principle like setting up a wifi router). It is quite likely that several weeks/months/years after installation a different maintenance engineer will attempt to log back into the device over the wifi hotspot.

I can't think of a way to do this securely and give ease of access for the maintenance engineer. The approach adopted so far is to:

  • Have the same WPA2 password for all devices (or made slightly different based on the units SSID).

This just seems to be asking for trouble though if one gets compromised the rest are potentially compromised. If we make the passwords unique and random for each unit then there is a reasonable chance the maintenance engineers will lose them - requiring the unit to be physically retrieved (not easy). Alternatively it may just be too much hassle for the maintenance engineer to use this product as password storage isn't something they are used to.

Other options we have considered are:

  • Only have the wifi on for a limited time after installation (or power up). Power cycling the device would re-start wifi (this is easier for the maintenance engineer and only they could do it). Seems like a bit of a hack though.
  • Some kind of scheme where the ssid is easily known but a web server, which would be the only port open, is password protected. I'm guessing for the following but possibly to get the password would require getting a token from the web browser, send that to our server, then a response would gain access to the web pages. The problem here though, if the scheme works at all, would be if the engineer didn't have access to the internet on site this wouldn't work.

What is best practice though for this situation? (I should also add if we are compromised it would just be embarrassing not a safety critical situation or anything like that). Thanks.

  • I don't get it, this "devices" are the STA or the AP? By 'hotspot' you mean a public one, or one you manage or a 3G/4G they bring? And where do they login? Your managed whatever or their own "device"? You said "in principle like a Wi-Fi router" so I'ts fine to assume they use the hotspot to get internet, like a signal extender? Can you please illustrate some more?
    – Azteca
    Apr 27 '17 at 15:40

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