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submitted 6 months ago by petsoi@discuss.tchncs.de to c/linux@lemmy.ml
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[-] Kata1yst@kbin.social 4 points 6 months ago

I strongly disagree with your premise. Separating authentication and privilege escalation adds layers of security that are non-trivial and greatly enhance resilience. Many attacks are detected and stopped at privilege escalation, because it happens locally before a user can stop or delete the flow of logs.

If I get into your non-privileged account I can set up a program that acts like sudo

No you cannot. A non privileged user doesn't have the access necessary to run a program that can accomplish this.

And even if they do it’s too late anyway because I’ve just compromised root and locked everybody out and I’m in there shitting on the filesystems or whatever. Because root can do anything.

Once again, you didn't privilege escalate, because once you have a foothold (authentication) you don't have the necessary privileges, so you must perform reconnaissance to identify an exploitable vector to privilage escalate with. This can be any number of things, but it's always noisy and slow, usually easy to detect in logs. There is a reason the most sophisticated attacks against well protected targets are "low and slow".

And if I can’t break into your non-privileged account then I can’t break into a privileged account either.

You're ignoring my points given regarding the risks of compromised keys. If there are no admin keys, there are no remote admin sessions.

These artificial distinctions between “non-privileged” and “superuser” accounts need to stop. This is not good security, this is not zero trust. Either you don’t trust anybody and enforce explicit privilege escalation for specific things, or just accept that you’re using a “super” paradigm and once you’ve got access to that user all bets are off.

Spoken like someone who has never red teamed or purple teamed. Even admin accounts are untrusted, given only privileges specific to their role, and closely monitored. That doesn't mean they should have valid security measures thrown away.

[-] lemmyvore@feddit.nl 2 points 6 months ago

A non privileged user doesn't have the access necessary to run a program that can accomplish this.

It would be a script called "sudo" somewhere in your PATH. You type sudo, you give it your password, done.

[-] Kata1yst@kbin.social 3 points 6 months ago

That's called 'privilege escalation', and replacing system level calls with user level calls is closely watched for and guarded against with many different security measures including SELinux.

You've already outed yourself multiple times in this thread as someone who doesn't understand how security in the real world works. Take the L and try to learn from this. It's okay not to understand something. But it's very important to recognize when that happens and not claim to understand better than someone else.

[-] lemmyvore@feddit.nl 1 points 6 months ago

It's not privilege escalation because it doesn't subvert the correct authentication mechanism, it leverages it. This particular technique is called UI input capture. It's a script that shows a password prompt then uses your password to do things as root. Nothing untowards would be detected. The main defense is to always run commands with full path – which nobody does.

Separating the process of reaching root in two steps does nothing to improve security, it actually increases complexity and subverts security. If the system is set up to SSH as root you either have a good key or you don't. If you force people to SSH as individual users and then use a complex mechanism to reach root you create opportunity for a hundred more attack methods, and add a false sense of security.

Input capture btw is not the only method. Sudo has a lot of them. Another very common one is leveraging the password cache timeout.

You've already outed yourself

How about we skip the dick measuring contest and we stick to the discussion at hand.

this post was submitted on 09 May 2024
226 points (95.6% liked)

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