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Brute-forcing a macOS user’s real name from a browser using mDNS

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Re: Brute-forcing a macOS user’s real name from a browser using mDNS

#41

Earlier quoted context omitted.

I do the opposite: one of my laptops is named "Peter's iPhone" (hint: my name is not Peter, nor do I own an iPhone) and I've also set all my Bluetooth to random Bluetooth headset or mouse models.

My hotspot on my phone is "FBI van 4"

I wonder if I can sell my WiFI AP name to some advertiser...

"ENJOY COCA-COLA"

or more likely

"TOM BRADY SAYS BUY CRYPTO"

Re: Brute-forcing a macOS user’s real name from a browser using mDNS

#43

Earlier quoted context omitted.

My hotspot on my phone is "FBI van 4"

I see this joke frequently when looking at available wifi; is this meme a reference to a particular thing (other than the FBI having surveillance vans) or did a bunch of people just converge onto it?

I've never seen it. Maybe it's spreading like a fungus from wifi to wifi in certain regions.

Re: Brute-forcing a macOS user’s real name from a browser using mDNS

#44
post #25
post #21

Earlier quoted context omitted.

Technically they can make the request. The server will receive and respond to the request. CORS is applied by the browser which prevents the response from being read. This is why CORS doesn't prevent a request from mutating something on a server. A CSRF token does.

Is that true? There’s a preflight request that checks with the server as to what’s allowed and then the browser issues the original request if it’s ok, right?

First of all, you could probably do a timing attack on CORS response, you'd just have to deal with how much they're cached.

Depends on the resource request. For example, can be used to load remote resources without CORS, since the image data isn't shared with JS (trying to read it via a canvas marks it "tainted", and errors read requests). Meltdown/Spectre breaks this barrier down, which led to the introduction of COOP/COEP headers that require CORS on remote requests and would break this attack—except that you can ask the browser to send requests without cookies, re-introducing this timing attack.

Re: Brute-forcing a macOS user’s real name from a browser using mDNS

#45
post #19

Earlier quoted context omitted.

I used to do something similar with my router. I would run an AP called "Linksys" or something common and give it an OUI belonging to Cisco. It probably had no benefit (maybe even harmful!), but it was fun to "disguise" my OpenBSD router as a common off the shelf router.

I name my computer: 'router'

To be fair, it probably will route if you ask it.

Re: Brute-forcing a macOS user’s real name from a browser using mDNS

#46

Is there a way to prevent websites from the broader Internet from making network requests to my local network? I can't imagine why this should be allowed by default. (Not to suggest bringing back IE's Local Intranet Zone permission...)

https://developer.chrome.com/blog/private-network-access-pre... is one idea being actively worked on in this area

Re: Brute-forcing a macOS user’s real name from a browser using mDNS

#48

Is there a way to prevent websites from the broader Internet from making network requests to my local network? I can't imagine why this should be allowed by default. (Not to suggest bringing back IE's Local Intranet Zone permission...)

https://developer.chrome.com/blog/private-network-access-pre... is one idea being actively worked on in this area

>This content is outdated and no longer accurate. New material available.

The "new material" is https://developer.chrome.com/blog/private-network-access-upd... and changed from restricting all "public websites" to only restricting non-HTTPS sites.

It does at least say:

>Restricting private network requests to secure contexts is only the first step in launching Private Network Access.

... so maybe it'll become better later.

Re: Brute-forcing a macOS user’s real name from a browser using mDNS

#49

Is there a way to prevent websites from the broader Internet from making network requests to my local network? I can't imagine why this should be allowed by default. (Not to suggest bringing back IE's Local Intranet Zone permission...)

Yes. Change the client. For example, I'm using one that does not auto-load resources, does not run Javascript and does not perform DNS prefetching. There is no way for the website (cf. user) to make network requests.

This experiment is of course limited to users who do not change defaults, since any MacOS user can easily change their hostname to anything they want, and that is quite easy to do, even for people who do not read HN. The "real name" might not be real if the user has changed the default. Is there any reliable way for the website to distinguish "real" from "fake" names in MacOS hostnames.

Re: Brute-forcing a macOS user’s real name from a browser using mDNS

#50

Is there a way to prevent websites from the broader Internet from making network requests to my local network? I can't imagine why this should be allowed by default. (Not to suggest bringing back IE's Local Intranet Zone permission...)

uBlock Origin ships with a (default disabled) “Block Outsider Intrusion into LAN” blocklist, it has some default exclusions though. https://github.com/uBlockOrigin/uAssets/blob/01eba0c1445c881...

And, indeed, when I run the PoC from the article, all the requests are blocked by uB0.

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