Why do so many companies and people say that your password has to be so long and complicated, just to have restrictions?

I am in the process of changing some passwords (I have peen pwnd and it’s the password I use for use-less-er sites) and suddenly they say “password may contain a maximum of 15 characters“… I mean, 15 is long but it’s nothing for a password manager.

And then there’s the problem with special characters like äàáâæãåā ñ ī o ė ß ÿ ç just to name a few, or some even won’t let you type a [space] in them. Why is that? Is it bad programming? Or just a symptom of copy-pasta?

  • Aurenkin@sh.itjust.works
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    1 year ago

    A very high max of something like 500 characters just to make sure you don’t get DOSed by folks hitting your endpoint with huge packets of data is about the most I would expect in terms of length restrictions. I’m not a security expert or anything though.

    • dog@suppo.fi
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      1 year ago

      That’s a misunderstanding of DDoS. 0 byte packets are actually worse than large packets.

      Which is why most DDoS (at least was) is extremely slow 0 byte requests until the server throttles/crashes under the number of requests.

      E: Consider this. Are you more likely to throttle a bandwidth of terabytes/petabytes with couple million 1gb requests; or break it entirely by sending >4294967295 0 byte requests that effectively never stop being requested from the server?

      • kevincox@lemmy.ml
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        1 year ago

        It depends on what the DoS is targeting. If hashing is being done with an expensive hash function you can absolutely cause a lot of resource usage (CPU or memory depending on the hash) by sending long passwords. That being said this likely isn’t a huge concern because only the first round needs to process the whole submitted data, the later rounds only work on the previous round’s output.

        Simple empty requests or connection opening attempts are likely to be stopped by the edge services such as a CDN and fleet of caches which are often over-provisioned. A targeted DoS attack may find more success by crafting requests that make it through this layer and hit something that isn’t so overprovisioned.

        So yes, many DoS attacks are request or bandwidth floods but this is because they are generic attacks that work on many targets. But that doesn’t mean that all DoS attacks work this way. The best attacks target specific weaknesses in the the target rather than pure brute-force floods.

        • dog@suppo.fi
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          1 year ago

          Well to be fair, if they’re hashing serverside, they were doomed to begin with.

          But yeah, there’s a lot of ways to DDoS, and so many tools that just make it a 1 button click.

          • kevincox@lemmy.ml
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            1 year ago

            Who isn’t hashing server-side? That just turns the hash into the password which negates a lot of the benefits. (You can do split hashing but that doesn’t prevent the need to hash server-side.)

            • dog@suppo.fi
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              1 year ago

              Hashing on client side is both more private, and secure. All the user ever submits is a combined hash (auth/pubkey) of their username + password.

              If the server has that hash? Check the DB if it requires 2FA, and if the user sent a challenge response. If not, fail the login.

              Registering is pretty much the same. User submits hash, server checks DB against it, fail if exists.

              Edit: If data is also encrypted properly in the DB, it doesn’t even matter if the entire DB is completely public, leaked, or secured on their own servers.