[saganus]

I'm neither a sysadmin nor a securyt expert, so I might be terribly wrong, but, as I understood it, password-based authentication was undesirable because the attacker could try to brute-force it.

Key-based auth doesn't have this flaw so it's arguably safer in that it has one less entry point.

On the other hand, not sure I fully understand your argument. You are saying that not being vulnerable to password brute-forcing is not enough since you could still hack the server? or what exactly do you mean by "just shifts the weak point ... to another"?

[freehunter]

>what exactly do you mean by "just shifts the weak point ... to another"?

I'm not the person who made that argument, but I can give you my reasoning to support it.

Your key is on your laptop and unlocks your server, now your server is safe. But your laptop is just secured with a password. I brute-force the password on your laptop, and now I have no barriers preventing me from accessing your server. Your server is secure, sure, but the risk was just pushed back to your laptop which may be more or less easy to compromise than your server (depending on the threat).

I'm not arguing that key-based authentication isn't a good step forward. If you're using passwords on your Internet facing servers, stop doing that and start using keys. But you also have to protect your keys and any machine those keys are installed on, otherwise you're just shifting the weak point to another machine.

[tachyoff]

> But you also have to protect your keys and any machine those keys are installed on, otherwise you're just shifting the weak point to another machine.

I’m okay with this, personally. What’s riskier: a public server listening on port 22 for any SSH traffic or my personal laptop which doesn’t accept random requests from the entire internet and is almost never out of my sight? And even if someone compromised my machine (e.g. theft), they probably don’t care or even understand what SSH keys are; they’ll probably just wipe the thing and sell it on the black market.

That’s not a good reason to ignore sound security practices, but threat model-wise, my laptop is much less likely to be targeted and successfully compromised physically by someone who wants to SSH into my build server.

[freehunter]

Your laptop, maybe. It sounds like you understand security, which is good. Not everyone does. I'll give you an example:

I have a picture I like to use in my presentations where I was at a mostly-empty family restaurant and the person sitting next to me (alone) had their laptop sitting out and went to the bathroom without even locking the screen. In 15 seconds I could have popped in a USB drive and copied all of his SSH keys (and more) without anyone ever noticing. It could have been done before he even reached the bathroom door, let alone came back. I don't think you would do this, of course, but some people do. And your coworkers might.

On top of that, about 25%-30% of security incidents are caused by insider threats. Considering how easy attacks over the Internet are, that's an absolutely massive number. Even if your laptop never leaves your desk, it's entirely possible someone within your company might want to do some harm to you or the company and it might be the desktop support technician hooking up your new monitor while you grab another cup of coffee.

Your point about what's riskier is completely true: if you have Internet-facing servers using passwords, stop that and use keys. But when you do that, you need to study up on the new risks you may not be aware of. Security shouldn't just be a curtain you close. Companies/people who don't understand this love paying me shitloads of money to explain it to them :)

[parliament32]

Why would you not have a passphrase on your key? Passphrase encryption is the default in ssh-keygen and probably every other ssh key generation utility. Having a magic file that grants access to a server scares the crap out of me -- but use the passphrase feature and it's far more secure than password auth.

[freehunter]

You'd be surprised. ssh-keygen allows you to just hit enter and bypass the passphrase with no hoops to jump through and insufficient warning (IMO). Maybe that should be changed. But right now it's all too easy and convenient.

[parliament32]

Well yes, but you're explicitly ignoring instructions at that point.

But I agree, making it more difficult (force the user to consult the man page and look up the flag -- see openssl cert generation) would be better.

[dvfjsdhgfv]

> Key-based auth doesn't have this flaw so it's arguably safer in that it has one less entry point.

This is exactly what people think when reading the guides. In fact, it's not that there is one less entry point, but this entry point was moved and now exists on another machine together with the key. And since many people use one workstation to log in to several servers, you now have one single point of failure (an equivalent of using one password for all servers).

[icebraining]

That SPOF exists with passwords too; a keylogger in the workstation will capture them all.

[saganus]

Yeah, I see your point.