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    Securing SSH

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    ssh ssh keys security
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    • hobbit666
      hobbit666 @DustinB3403 last edited by

      @DustinB3403 I've already got the password on the keys. I've just not disabled password logins in case i kill something and need to get access :). Planning on removing it once i've "SSH Key's" the other servers.

      DustinB3403 P 2 Replies Last reply Reply Quote 0
      • DustinB3403
        DustinB3403 @hobbit666 last edited by

        @hobbit666 said in Securing SSH:

        @DustinB3403 I've already got the password on the keys. I've just not disabled password logins in case i kill something and need to get access :). Planning on removing it once i've "SSH Key's" the other servers.

        Have you confirmed that key based login works? If so, then you login as [email protected] and elevate to root. Disable root login period via ssh and only allow elevation.

        1 Reply Last reply Reply Quote 0
        • P
          pmoncho @hobbit666 last edited by

          @hobbit666 said in Securing SSH:

          @DustinB3403 I've already got the password on the keys. I've just not disabled password logins in case i kill something and need to get access :). Planning on removing it once i've "SSH Key's" the other servers.

          Don't forget, you can still login as root or a admin user on the console. You are only securing ssh.

          If you want to test, login to the console of the server (stay logged in), change your sshd_config, restart sshd process, test logging in with your keys and/or any other testing you want to do. If all is well, log out of the console.

          1 Reply Last reply Reply Quote 2
          • wirestyle22
            wirestyle22 @JaredBusch last edited by wirestyle22

            @JaredBusch said in Securing SSH:

            @hobbit666 said in Securing SSH:

            @Dashrender To be honest that's my next step is now to make some keys for my laptop, and see how and where they go 🙂
            but my guess is in the same authorized_keys file on a separate line

            This is your friend.

            ssh-copy-id -i ~/.ssh/id_ed25519.pub [email protected]
            

            if you only have a single public key you can simplify it to

            ssh-copy-id [email protected]
            

            I specify because my desktop has a few different generated keys.
            3ff95aa0-de1f-4a83-b1c3-74c0919f78c8-image.png

            How does this fit into disaster recovery plans when you have many hundreds of ssh keys and a large IT team? If one person has 100 keys to various servers and their laptop dies, are you guys using a script to copy the keys per user? Also new user creation or deleting keys when someone leaves

            JaredBusch coliver 2 Replies Last reply Reply Quote 1
            • JaredBusch
              JaredBusch @wirestyle22 last edited by

              @wirestyle22 said in Securing SSH:

              @JaredBusch said in Securing SSH:

              @hobbit666 said in Securing SSH:

              @Dashrender To be honest that's my next step is now to make some keys for my laptop, and see how and where they go 🙂
              but my guess is in the same authorized_keys file on a separate line

              This is your friend.

              ssh-copy-id -i ~/.ssh/id_ed25519.pub [email protected]
              

              if you only have a single public key you can simplify it to

              ssh-copy-id [email protected]
              

              I specify because my desktop has a few different generated keys.
              3ff95aa0-de1f-4a83-b1c3-74c0919f78c8-image.png

              How does this fit into disaster recovery plans when you have many hundreds of ssh keys and a large IT team? If one person has 100 keys to various servers and their laptop dies, are you guys using a script to copy the keys per user? Also new user creation or deleting keys when someone leaves

              No one has 100 keys unless they have 100 desktops.

              But yes. you can easily script this.

              See:

              @scottalanmiller said in Securing SSH:

              Correct. We put our public keys into scripts to deploy and have them listed on a wiki, too. So that it is easy to add users to a system.

              1 Reply Last reply Reply Quote 1
              • coliver
                coliver @wirestyle22 last edited by

                @wirestyle22 said in Securing SSH:

                @JaredBusch said in Securing SSH:

                @hobbit666 said in Securing SSH:

                @Dashrender To be honest that's my next step is now to make some keys for my laptop, and see how and where they go 🙂
                but my guess is in the same authorized_keys file on a separate line

                This is your friend.

                ssh-copy-id -i ~/.ssh/id_ed25519.pub [email protected]
                

                if you only have a single public key you can simplify it to

                ssh-copy-id [email protected]
                

                I specify because my desktop has a few different generated keys.
                3ff95aa0-de1f-4a83-b1c3-74c0919f78c8-image.png

                How does this fit into disaster recovery plans when you have many hundreds of ssh keys and a large IT team? If one person has 100 keys to various servers and their laptop dies, are you guys using a script to copy the keys per user? Also new user creation or deleting keys when someone leaves

                There is also a way to do a trusted key broker. So you have a single CA that verifies your identity.

                stacksofplates 1 Reply Last reply Reply Quote 1
                • stacksofplates
                  stacksofplates @coliver last edited by

                  @coliver said in Securing SSH:

                  @wirestyle22 said in Securing SSH:

                  @JaredBusch said in Securing SSH:

                  @hobbit666 said in Securing SSH:

                  @Dashrender To be honest that's my next step is now to make some keys for my laptop, and see how and where they go 🙂
                  but my guess is in the same authorized_keys file on a separate line

                  This is your friend.

                  ssh-copy-id -i ~/.ssh/id_ed25519.pub [email protected]
                  

                  if you only have a single public key you can simplify it to

                  ssh-copy-id [email protected]
                  

                  I specify because my desktop has a few different generated keys.
                  3ff95aa0-de1f-4a83-b1c3-74c0919f78c8-image.png

                  How does this fit into disaster recovery plans when you have many hundreds of ssh keys and a large IT team? If one person has 100 keys to various servers and their laptop dies, are you guys using a script to copy the keys per user? Also new user creation or deleting keys when someone leaves

                  There is also a way to do a trusted key broker. So you have a single CA that verifies your identity.

                  Right there's a few ways to do this. Key management through LDAP, SSH certs with a CA, rotating credentials with something like Vault, etc.

                  IRJ 1 Reply Last reply Reply Quote 0
                  • IRJ
                    IRJ @stacksofplates last edited by

                    @stacksofplates said in Securing SSH:

                    @coliver said in Securing SSH:

                    @wirestyle22 said in Securing SSH:

                    @JaredBusch said in Securing SSH:

                    @hobbit666 said in Securing SSH:

                    @Dashrender To be honest that's my next step is now to make some keys for my laptop, and see how and where they go 🙂
                    but my guess is in the same authorized_keys file on a separate line

                    This is your friend.

                    ssh-copy-id -i ~/.ssh/id_ed25519.pub [email protected]
                    

                    if you only have a single public key you can simplify it to

                    ssh-copy-id [email protected]
                    

                    I specify because my desktop has a few different generated keys.
                    3ff95aa0-de1f-4a83-b1c3-74c0919f78c8-image.png

                    How does this fit into disaster recovery plans when you have many hundreds of ssh keys and a large IT team? If one person has 100 keys to various servers and their laptop dies, are you guys using a script to copy the keys per user? Also new user creation or deleting keys when someone leaves

                    There is also a way to do a trusted key broker. So you have a single CA that verifies your identity.

                    Right there's a few ways to do this. Key management through LDAP, SSH certs with a CA, rotating credentials with something like Vault, etc.

                    You can do this something like Okta ASA as well.

                    https://help.okta.com/en/prod/Content/Topics/Adv_Server_Access/docs/asa-overview.htm

                    1 Reply Last reply Reply Quote 1
                    • stacksofplates
                      stacksofplates last edited by

                      Another really good option is not letting them log directly into the systems at all and forcing them to use a config management tool. So something like Tower or a Jenkins server that logs all of the commands run and has the permissions set there.

                      scottalanmiller 1 Reply Last reply Reply Quote 4
                      • scottalanmiller
                        scottalanmiller @stacksofplates last edited by

                        @stacksofplates said in Securing SSH:

                        Another really good option is not letting them log directly into the systems at all and forcing them to use a config management tool. So something like Tower or a Jenkins server that logs all of the commands run and has the permissions set there.

                        Right. Just like the best defense is a good offense (or vice versa?) The most secure port, is a closed port. Locking down SSH, no matter how good, isn't as good as completely closing it.

                        Or using config management to only open it when necessary, is an "in between" step, too.

                        1 Reply Last reply Reply Quote 1
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