Windows – How to prevent Windows 10 from sharing wifi details with the contacts

encryptionSecuritywifisensewindows 10wireless-networking

In recent release of Windows 10 we could see a new feature named wifi sense, which raised the following security threat as per this blog post :

This brilliant new feature, which Microsoft has dubbed Wi-Fi Sense,
doesn’t share your WiFi network password per se — it shares an
encrypted version of that password. But it does allow anyone in your
Skype or Outlook or Hotmail contacts lists to waltz onto your Wi-Fi
network — should they ever wander within range of it or visit your
home (or hop onto it secretly from hundreds of yards away with a good
‘ole antenna!).

As per faq :

For networks you choose to share access to, the password is sent over
an encrypted connection and stored in an encrypted file on a Microsoft
server, and then sent over a secure connection to your contacts’ phone
if they use Wi-Fi Sense and they’re in range of the Wi-Fi network you
shared

From Ars Technica :

First, a bit of anti-scaremongering. Despite what you may have read
elsewhere, you should not be mortally afraid of Wi-Fi Sense. By
default, it will not share Wi-Fi passwords with anyone else. For every
network you join, you’ll be asked if you want to share it with your
friends/social network

From the above excerpts it's unclear whether Windows 10 shares wifi details with my contacts; So my questions were few :

Does it really shares WiFi details with my contacts since many articles states it's shared & it's not shared.

If it's shared how can I prevent it?

Best Answer

If it's shared how can I prevent it?

You need to give your wireless network a new name with "_optout" somewhere in the Wi‑Fi network name (also called the SSID).

Note:

  • If you also want to opt out of Google's WiFi network mapping you will also need to include "_nomap" as well in your SSID.

Recommendation

  1. Prior to upgrade to Windows 10, change your Wi-Fi network name/SSID to something that includes the terms "_nomap_optout".

  2. After the upgrade is complete, change the privacy settings in Windows to disable Wi-Fi Sense sharing.

  3. If you haven’t already done so, consider additional steps to harden the security of your Wi-Fi network.

Source Windows 10 Shares Your Wi-Fi With Contacts

If you run a Wi-Fi network and you want to prevent Windows 10 (or Windows Phone) users from sharing the passkey via Wi-Fi Sense, you can add _optout to the end of the network SSID. Microsoft notes that, even if you opt out in this way, "It can take several days for your network to be added to the opted-out list for Wi-Fi Sense."

Source Wi-Fi Sense in Windows 10: Yes, it shares your passkeys; no, you shouldn’t be scared

I'm sharing a network and want to stop it. How do I do that?

If you're sharing Wi‑Fi network access and want to stop sharing a certain network, do the following:

To stop sharing access to a Wi‑Fi network

  • Go to Start Start icon > Settings > Network & Internet > Wi‑Fi > Manage Wi‑Fi settings.

  • Under Manage known networks, select the network that you want to stop sharing access to, and then select Stop sharing.

  • It can take a few days for the network to stop being shared. This is also true if a user is already connected to the network.

If you want to stop sharing all Wi‑Fi networks that you're currently sharing, go to Start Start icon > Settings > Network & Internet > Wi‑Fi > Manage Wi‑Fi settings, and then turn off Connect to networks shared by my contacts under Wi‑Fi Sense. It can take a few days for the networks to which you've shared access to stop being shared. When you turn this setting off, you won't get connected to Wi‑Fi networks that your contacts have shared with you.

Source Wi‑Fi Sense FAQ

How do I opt my Wi‑Fi network out of Wi‑Fi Sense?

If you don't want Wi‑Fi Sense to connect people to your open Wi‑Fi network or allow people to share access to your password-protected network, you can opt your network out of it by including _optout somewhere in the Wi‑Fi network name (also called the SSID). For example, mynetwork_optout or my_optout_network. When it comes to sharing, you might choose to do this if you have a Wi‑Fi network at home or at a small business where other people know the Wi‑Fi network password, but you don’t want to allow your network to be shared.

Source Wi‑Fi Sense FAQ

How to disable Wi-Fi Sense in Windows 10

First, open the Start menu and head to Settings > Network & Internet > Wi-Fi > Manage Wi-Fi settings. In here, you basically want to disable every option you see, as well as tell Windows 10 to forget any Wi-Fi networks you’ve signed into in the past.

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That’s easy, and all well and good. But what if you don’t want your friends sharing the information about your network’s password with their friends? That takes some additional tinkering, and it’s not obvious. There isn’t a mere option toggle in Windows 10 itself.

Instead, you need to dive into your actual router’s settings and give your network a new name with “_optout” at the end. For example, a network called “WiFiSenseUgh_optout” wouldn’t be stored by Wi-Fi Sense, while one that’s just called “WiFiSenseUgh” would be usable with Microsoft’s sharing feature.

Yeah, it’s a pain, but if you don’t add “_optout” to your network and want to stay out of Microsoft’s Wi-Fi Sense database, you’ll need to manually enter your password on your friends’ devices when they pop by your house and make sure to uncheck Windows 10’s “Share network with my contacts” box when you do so.

Source How to disable Windows 10's Wi-Fi Sense password sharing

The Microsoft server might already have a copy of my wifi credentials.

You can change your Wifi credentials. It is a good idea to regularly change them in any case.

It can take several days for your network to be added to the opted-out list for Wi‑Fi Sense. If you want to stop your network from being shared sooner than that, you can change your Wi‑Fi network password. For more info about how to do that, check the documentation for your router or access point.

Source Wi‑Fi Sense FAQ

How do I opt out from Google's Location Mapping?

How do I prevent my wireless access point from being collected?

Mozilla's client applications do not collect information about WiFi access points whose SSID is hidden or ends with the string "_nomap". If you would like to prevent your WiFi access point from being reported to this service, you can rename your SSID to append "_nomap" to the name (e.g., SSID "MyWirelessNetwork" becomes "MyWirelessNetwork_nomap") or configure your SSID to be hidden.

This approach is used by other companies offering similar services. We have chosen to follow the example established by others, to make sure you do not have to learn about specific ways to opt-out of this service, but can generally signal your desire to do so and have that signal be respected by multiple services.

Source How do I prevent my wireless access point from being collected?

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