In late 2014, Windows Phone introduced a feature that not only automatically connects you to Wi-Fi networks but also shares your Wi-Fi password with your Facebook, Skype and Outlook “friends”.
It was called Wi-Fi Sense and this was F-Secure Security Advisor Sean Sullivan’s reaction: “So… if your phone knows the password to your company’s Wi-Fi network, now your Facebook friends can access it too. Information security managers are going to love that.”
Cut to 2015. The latest — and “final” — version of Windows is released with Wi-Fi Sense and suddenly a controversy that had been relegated to infosec blogs became the biggest privacy issue of the biggest software launch of the year (though other issues definitely require your attention).
F-Secure’s Tomi Tuominen tweeted:
We asked Tomi to elaborate on what sort of abuse he might expect as millions of users upgrade to Windows 10.
“We have seen many cases where an attacker has taken over a service to get access to something else,” he explained. “Now, with Wi-Fi Sense it is enough to befriend with somebody in your ‘circles’ to
get access to your home Wi-Fi or office Wi-Fi, since not all office Wi-Fi is secured using enterprise settings. Then this person can eavesdrop and even do man-in-the-middle or targeted attacks.”
Is there any reason you’d want to keep it on?
“No. I just think it is a horrible idea.”
It’s pretty simple to turn off, if you’ve activated it. However, protecting your Wi-Fi network from other people using Wi-Fi Sense — by changing your Wi-Fi network name/SSID to something that includes the terms “_nomap_optout” — requires a technical leap few users will likely make.
So why is Microsoft doing this? Here’s how it explains the feature.
“Effectively they are trying to do something that is technically very difficult to do and very prone to human errors.”
Tomi calls it “transient trust,” which is great and theory and very difficult to control in practice.
“Imagine a situation where a relationship ends,” he explained. “The other person is still in your Skype contacts but you forget that your she or he has access to your Wi-Fi sharing. Your ex will be able to eavesdrop all your traffic if s/he is on the range. And this is a situation where everything is working as it should!”
Microsoft has designed Wi-Fi Sense so that you do need to opt into sharing your password with contacts. But the consequences of the checkboxes we click all day long are difficult for many to conceive.
“How many people just go ‘Next!’ clickety-click?” he asked. “Most people never touch the default settings.”
But there’s are further privacy issues to consider given the “transient trust” era we’re now in.
If tech giants like Microsoft are going to assume that our “friends” on Facebook and Skype are actually our real friends, we should make an effort to keep those lists as close to reality as possible.
Also: If all someone has to do to get your Wi-Fi access is to setup one Skype call, then it’s a good idea to always secure your Wi-Fi sessions wherever you’re connecting.
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