SSH Login using only Public-Private Key and Priv Levels

[NielsvdBerghe]

Hey, I'm trying to make a setup on my Cisco 881 router, but I'm having some trouble.

I've managed to configure logging in with a Public-Private key pair over SSH, but it's also still possible to log in over SSH with just a username and password. I'd like to prevent this, if possible. I imagine I might have manually configured this to be allowed at some point, but I can't quite figure out how I did this, as no matter what I've tried to remove, it keeps allowing this option. I still need to be able to log in with a username, because I want users to have different privileges. Which brings me to my second problem...

Once I've logged in using the Public-Private key, I don't automatically go into privilege mode, even though the user is configured with a privilege level. I'd like to configure that users that I've configured to use a certain privilege mode, automatically go into privilege mode without a password prompt. I know it did this before I started using the Public-Private key (or before I used AAA, which was configured around the same time), so I wondered if it's possible to do this still.

If anyone needs a part of my configuration in order to help, just ask for the part that you need and I'll post it.

Thanks in advance for anyone trying to help!

[Chris Illsley]

Hi Niels,

Wrong section, try putting it in AAA, Identity and NAC.

Thanks

Chris

[NielsvdBerghe]

I've figured out how to make a user go straight into privilege mode and have lower ranking users not go into a higher privilege level. After configuring AAA, I used these commands:

(config)#aaa authorization exec default local
(config)#aaa authorization console
(config)#enable secret password

Now my last problem is with the SSH password login. I've configured to use a Public-Private keypair to login and this works just fine. The problem is that the router still allows people to log in using a regular password when they don't have a key. Anyone know how to fix this?

[Karsten Iwen]

To restrict users to only do pubkey-authentication you need to remove the secret/password from the regular user-account:

username test privilege 15

That way the user can only log in with the stored public key information and still gets directly to privilege 15.


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[NielsvdBerghe]

I've tried removing the password from the user, but it didn't quite work out. It still allows you to login without a key, only now you don't input anything when it asks for a password.

[Karsten Iwen]

well, that's not how its supposed to be ...

Did you accidently use the "nopassword" keyword instead of removing the secret/password?

Wenn you do a "show run | i username" it should be in the form above.

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[NielsvdBerghe]

When I do a "show run | i username", this is what I get:

username admin privilege 15

  username admin

Is it possible that I'm allowing the password prompt through a command I've used somewhere?

[Karsten Iwen]

I just tested it again and you are right. I completely remembered wrong about how that worked. You could specify a long and random password that the user doesn't know. That would restrict it to pubkey-logins. Not very elegant but should work.

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