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Comment by ancarda | Hacker News Reader

>Crab is listening on the communication capturing the message.

Can we stop here and have a discussion about this? Every example I have ever seen of interception is either "coffee shop Wi-Fi" or government surveillance. Are those the main threats?

"Coffee shop Wi-Fi" seems like less of a threat each year. AFAIK WPA 3 means you get an ephemeral encryption key when you connect. Additionally, tethering seems to be more and more common these days. Both solve this problem, no?

Government surveillance is a different topic, but given how prevalent TLS termination is (any website using CloudFlare, for a start), I'm not so sure it helps - the NSA probably still have all your data.

Who is crab nowadays? Is he still a threat? Do we still need TLS even with WPA 3?

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> Are those the main threats?

Maybe? Your threat model may vary. If you're very focused on happy news, most people's network use is not tampered with in a way that directly interferes with their enjoyment most of the time. If that's really all you wanted then you can reason TLS is unnecessary for you†

If the coffee shop uses WPA3 and not any older version (do you check?) and if you have your own secret password for the coffee shop WiFi not shared with anybody else (do you?) then WPA3 means crab probably cannot impersonate your coffee shop's WiFi router by hanging out in the coffee shop, although there are plenty of problems in practice with WPA3 implementations.

But what if crab runs the coffee shop WiFi anyway? Do you interview coffee shop owners about who provides their WiFi? It's just a cheap way to keep customers in the shop (if it's the sort of coffee shop that wants to do that) and who provides it and why isn't top of the owner's mind.

Maybe the family owned coffee shop just uses the stock ISP WiFi router and they're paying $50 per month like everybody else in the neighbourhood for Internet access. But, is that ISP the most scrupulous business? They can make money if they inject advertisements into your browsing, or if they can at least associate your address to specific browsing activity so that can be monetized. Perhaps even if the ISP itself is high-minded enough to turn these opportunities down an individual ISP employee is not, network engineers can certainly choose to eavesdrop easily enough.

† But you aren't using TLS just for you. We must all hang together or most assuredly we shall all hang separately. If only a relative minority of people use protocols which provide them with features like confidentiality, those people stand out more easily to be attacked. Don't Stand Out is an increasingly important property to protect us all by sheer numbers.

> most people's network use is not tampered with in a way that directly interferes with their enjoyment most of the time. If that's really all you wanted then you can reason TLS is unnecessary for you

I would go beyond that and say that the reason most networks people use do not tamper with the traffic is because most people use TLS nowadays. Not too long ago, it was very common for networks to use a "transparent HTTP proxy", intercepting all TCP port 80 traffic and redirecting it to a separate box with a caching HTTP proxy like Squid, in an attempt to reduce the traffic. This sucked whenever the HTTP proxy misbehaved (which was not uncommon; many operators seemed to configure it to cache more than it should). Since nowadays most HTTP traffic is protected by TLS, transparent caching HTTP proxies no longer provide a relevant reduction in the bandwidth use, and so they became less common.

The coffee shop router is the thread. Whether it's the coffee shop owner, an employee, somebody who hacked the router or just somebody who tricked you into going into their WiFi which is not actually the coffee shop's.

I don't have data on this, but I suspect usage of public Wi-Fi is going to keep declining in favor of cellular data as it becomes cheaper and data caps rise/go away

So, in that case, would TLS still be useful? It just seems like quite a lot of effort to ensure TLS everywhere because a small number of people use untrustworthy Wi-Fi networks

> So, in that case, would TLS still be useful?

Because again the scope of encryption offered by wireless operators is different from TLS. It is like asking if encrypting your disks makes TLS pointless.

TLS encrypts traffic between your computer, and some resource on the internet.

WPA3 encrypts communication between your computer and the wireless access point, no further. The wireless provider's encryption will similarly only encrypt data between your device and the wireless provider's equipment.

They are not designed to do the same thing. Technically WPA3 and and other wireless networking encryption is not needed if you are using TLS, because the scope of encryption of TLS covers the data going to your wireless provider or the wireless access point, but not everything is TLS - and even TLS still leaks DNS in many cases. And even if it was not leaking DNS there are still things that would be better for others to not know when you are using TLS.

Just out of curiosity, I wonder how many layers of encryption one can reach in a day-to-day usage scenario.

TLS keeps the traffic secret between the client and the server. Encryption on part of the transport - like the cellular net - only covers part of the journey, and is out of your control. It's the difference between sending a box locked or not - the box is routed between different operators and terminals.

I still regularly use Wifi, e.g. on trains in rural areas, because mobile data is a lot more unstable there compared to the train wifi, especially at speed in rural areas. (Trains here usually have better antenna and often uplinks to multiple carriers)

Then the mobile carrier/ISP is the threat. I personally do not really trust those DSLAM boxes scattered all around my city, often readily accessible by everybody with the right key/lock pick. E.g. I know the DSLAM box that is serving my house, and I can just walk up to it.

And every other hop between you and the destination is the threat as well, and every person having enough access to any such hop, from company employee to external attacker. Also, did China route half the internet through China again, by "accidental" buggy BGP routes.

And don't forget your own router, which is a threat (once hacked). Or that "smart" lightbulb or other IoT device in your LAN that may be able to listen to your all your Wifi communication at home depending on your setup.

TLS isn't "a lot of effort", it's a minor computational cost e.g. compared to the energy you use to display ads you don't want to see, and end-users do not have a hard time using it. It's a tiny bit of burden for server operators, tho letsencrypt/ACME made it a setup-once kinda thing for a lot of people.

You’re correct about the coffee shop wifi being less of a problem year on year. Though WPA3 only gets you as far as the access point you’re connecting to - you still have the rest of the networks your traffic will grace between that access point and your destination.

With TLS encrypting web traffic we’re trying to secure the traffic as it makes that journey, in combination with WPA3 we’re making use of defence in depth - rendering your coffee shop attacker useless.

It’s not just bad actors at the coffee shop or at the government level intercepting traffic though:

Less scrupulous ISP’s will intercept plaintext traffic, doing dynamic ad insertion, dynamic image compression, or (theoretically) scraping content to build profiles on their customers - personally I object to those behaviours.

Is it not good practice that firms doing SSL Termination at a third party should be forwarding traffic onto their own equipment using their own or different certificates?

I don’t think anyone should trust any computer on the networks between their browser and the site they’re browsing, the internet is a much less trustworthy place than it was in the 90’s.

> "Coffee shop Wi-Fi" seems like less of a threat each year. AFAIK WPA 3 means you get an ephemeral encryption key when you connect.

Encrypted to the router, which is managed by the "Coffee shop".

If you talk about encryption, it is important to consider the scope of it.

> Who is crab nowadays? Is he still a threat? Do we still need TLS even with WPA 3?

WPA 3 and TLS are not solving the same problem.

>Who is crab nowadays? Is he still a threat? Do we still need TLS even with WPA 3?

Yes. I take TLS and no Wlan crypto any day over the reverse.

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