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Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

news.ycombinator.com

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Re: Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

#51

Post by lexicality »

themartorana wrote: post #46

I've developed an app that lets you log on to your friends' Windows machines without having to know the password! Don't worry, it's just Facebook friends. Someone has to realize how dangerous this is. How would ANY corporation EVER allow a single Windows 10 machine to connect to their wifi, let alone contractors, or... Do they not realize how paranoid network admins are to begin with? Windows XP forever, I guess.

> Enterprise networks that use 802.1X can't be shared. If you connect to one of these enterprise networks at work or somewhere else, those network credentials won't be shared with any of your contacts.

Re: Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

#52

Post by joosters »

mikeash wrote: post #43
joosters wrote: post #37

Earlier quoted context omitted.

Could you actually design this feature in a way that didn't share all the raw WIFI passwords with Microsoft? I think it would be pretty difficult. Bear in mind though that Google probably knows your wifi password if you or a friend syncs their phone's authentication data. (Google's legal troubles were a separate issue btw)

I don't think it would be too difficult, design-wise. Have every Win10 installation generate a public/private key pair. Share the public key with MS. When you share a password with all your contacts, MS can send all of their public keys to you, where you then encrypt the password with them and send the results back to MS. MS can then send the encrypted passwords to the contacts, who can then retrieve the password wit…

Ah, but it's a per-user secret, not per-device. So each user needs a keypair which gets shared across all of their devices, transparently but also in a way that protects the private key from MS. Which sounds an awful lot like the original problem of sharing secret WIFI passwords without MS being able to read them...

I agree that it must be do-able, it's just tricky to make it work transparently and simply so every user benefits.

Re: Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

#53

Post by yuhong »

tzs wrote: post #38
MichaelGG wrote: post #18

Earlier quoted context omitted.

They could require "secure enclave" hardware. But that'd need cooperation with the NIC, too, eh? Most likely they mean "we disable the show password option".

Based on what I read on one of their FAQs, it is not as good as a secure enclave, but it is quite a bit better than simply not providing a show password option. The password is not stored on the devices of the people you share with. It's stored on Microsoft servers. When the device someone you have shared with notices that a network you've shared is available, it gets the key to connect, then presumably forgets it. I…

Reading the 802.11-2012 spec, one could send the ANonce to the server, and the server then could generate a SNonce and construct the PTK from the secret PMK stored on the server. This would be secure because the nonces are supposed to be random. I think group key change also depends only on the PTK. This would still be more secure than open WiFi because it would not possible to decrypt packets to/from from other stations with a different SNonce.

Re: Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

#56

Post by nly »

dd9990 wrote: post #24

"The only way to opt out of this "feature" is to change the name of your SSID to include _optout at the end" Google requires you to have "_nomap" at the end of SSIDs to "opt out" of certain services...

Why do they do this instead of just ignoring networks with hidden SSIDs?

Re: Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

#57

Post by nly »

tzs wrote: post #38
MichaelGG wrote: post #18

Earlier quoted context omitted.

They could require "secure enclave" hardware. But that'd need cooperation with the NIC, too, eh? Most likely they mean "we disable the show password option".

Based on what I read on one of their FAQs, it is not as good as a secure enclave, but it is quite a bit better than simply not providing a show password option. The password is not stored on the devices of the people you share with. It's stored on Microsoft servers. When the device someone you have shared with notices that a network you've shared is available, it gets the key to connect, then presumably forgets it. I…

You could extract the handshake nonces and do this easily enough. It's fairly pointless though because WPA2 uses a weak hash function, so your "contacts" would still be able to intercept enough to attempt to bruteforce your password.

Also this entire thing seems dumb. If you need to connect to Microsofts server before you have wifi then you already have data.

Re: Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

#58

Post by yuhong »

nly wrote: post #57
tzs wrote: post #38

Earlier quoted context omitted.

Based on what I read on one of their FAQs, it is not as good as a secure enclave, but it is quite a bit better than simply not providing a show password option. The password is not stored on the devices of the people you share with. It's stored on Microsoft servers. When the device someone you have shared with notices that a network you've shared is available, it gets the key to connect, then presumably forgets it. I…

You could extract the handshake nonces and do this easily enough. It's fairly pointless though because WPA2 uses a weak hash function, so your "contacts" would still be able to intercept enough to attempt to bruteforce your password. Also this entire thing seems dumb. If you need to connect to Microsofts server before you have wifi then you already have data.

I think it is to deal with data caps. And brute force is always possible if one has the 4-way handshake and the password is only useful if you are near enough to actually connect to the network. AFAIK the PSK uses PBKDF2.

Re: Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

#59

Post by unsignedint »

Asking people to change their SSID so the system won't share something they are not supposed to be sharing to begin with is very ridiculous. I really don't understand why this is not opt-in to begin with. Microsoft should be forcing people to put in _optin in their SSID to allow this feature to work if they are so inclined to use an SSID to regulate access. At least it would be semi-tolerable if there was a web form of some sort that I can simply put in BSSID so it gets blacklisted systemwide, but I don't think that's even there.

Re: Windows 10 “WiFi Sense” automatically leaks your wifi password to strangers

#60

Post by zyxley »

Aloha wrote: post #47

If you set up your network using radius, this becomes a non-issue radius is not horribly hard to set up either - its also not automatic, the user has to choose to share the wifi password - which they could do anyhow, as you've given it to them to connect. https://www.windowsphone.com/en-gb/how-to/wp8/connectivity/w... - Section: "I'm concerned about sharing WiFi networks. Can you tell me a little more?"

Radius?
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