Remove wireless info from Mac OS recovery mode utilities page

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Remove wireless info from Mac OS recovery mode utilities page

Have a 2011 MacBook Pro I’m preparing to sell. I’ve done all the usual things, signed out of everything, I’ve booted into the Mac recovery mode and deleted my hard drive, and reinstalled the OS with High Sierra. My plan is to just leave it at the factory default screen for the next user to set up, add a Mac account etc..

However, I noticed that if I boot back into the Mac recovery mode and the Mac OS utilities page, it still auto-connects to my home wireless network. Where is it saving this info? When I click the wireless icon in the top right, there’s no way that I can see from this page to “forget” my network, and now the security freak in me thinks that somehow a user could be able to get into the recovery mode keychain to see my wifi network password. Is there something I can do from the terminal to delete it from recovery mode?

Mac Pro

Posted on Mar 4, 2020 5:05 PM

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Answer 1

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nigelkay Author

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19 points

Mar 4, 2020 5:32 PM in response to nigelkay

Found the answer! You have to reset the PRAM/NVRAM to remove that info if you have previously logged into a wifi network in recovery mode.

How to reset PRAM/NVRAM

Turn off your Mac.
Press the power button.
Immediately press the Command+Option+P+R keys.
Hold the keys until your Mac restarts and you hear the startup sound.
Release the keys.

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Answer 2

Mar 4, 2020 5:57 PM in response to nigelkay

Great detective work!

This article is what Apple suggests you do:

What to do before you sell, give away, or trade in your Mac - Apple Support

They do not mention resetting the PRAM/NVRAM, but on the other hand, it means someone has to find you, then sneak back into the bushes near your house with that same computer, and they can ... log on.

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Answer 3

nigelkay Author

Level 1

19 points

Mar 4, 2020 5:19 PM in response to Grant Bennet-Alder

Yes but it actually reconnects to it using my wifi network password that I’ve entered previously. There is no option or way to make it forget, and it’s obviously storing my password somewhere in the recovery mode area.

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Answer 4

nigelkay Author

Level 1

19 points

Mar 5, 2020 8:09 AM in response to Grant Bennet-Alder

It’s more about knowing that password is saved somewhere and could be accessed. (Even in Recovery mode, I had no idea it stored wifi passwords.)

For example, in regular operating mode, Wifi passwords are saved in the keychain. Any future admin user can access the keychain and see the wifi password if you haven’t wiped it out. If you reuse your passwords elsewhere it’s a security risk.

I know the chances are very slim but a targeted hacker could do some some damage besides accessing your home wifi. It’s just due diligence as I’m very security conscious. Not quite tin-foil hat but very close :)

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Answer 5

Mar 5, 2020 8:15 AM in response to nigelkay

I must admit I am surprised to hear Wi-Fi password is ever stored in PRAM/NVRAM.

In Internet recovery, it creates about 25 RAM disks so that your drive is completely free to be erased and does not have to be functional. If Internet recovery needs to remember that password, PRAM/NVRAM is about the only place available.

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Answer 6

Mar 4, 2020 5:16 PM in response to nigelkay

Your Wi-Fi Network is right there in the air all around your Mac. Your Mac does not need to remember anything to show you the NAMEs of the networks it can see.

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Remove wireless info from Mac OS recovery mode utilities page

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