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    Cannot SSH using public key

    Scheduled Pinned Locked Moved IT Discussion
    ssh keysssh
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    • IRJI
      IRJ @DustinB3403
      last edited by

      @DustinB3403 said in Cannot SSH using public key:

      @IRJ And to confirm, you aren't using putty to generate the key pair?

      right.

      1 Reply Last reply Reply Quote 0
      • DustinB3403D
        DustinB3403
        last edited by

        Technically the guide I see here is showing RSA key pairs and not dsa, even though the instructions say to use

        ssh-keygen -t dsa

        . . .

        This will create the following files 2 files;
        /home/scan_man/.ssh/new_id_rsa.pub  ===> Public Key
        /home/scan_man/.ssh/new_id_rsa  ===> Private Key
        
        IRJI 1 Reply Last reply Reply Quote 0
        • travisdh1T
          travisdh1 @IRJ
          last edited by

          @IRJ First off, generate the key as the user, just to make everything that much simpler. Use sudo if you have to.

          sudo - scan_user keygen
          

          Then copy the public key wherever.

          sudo - scan_user ssh-copy-id scan_user@wherever
          

          If those throw an error, try without the - (that tells sudo to fully load the scan_user profile.)

          No mussing about with permissions, they are set coherently already.

          As @DustinB3403 said, Nessus will have to support the encryption. If they don't support at least RSA, all these "security" things they tell you to do is not worth anything.

          IRJI 1 Reply Last reply Reply Quote 1
          • IRJI
            IRJ @DustinB3403
            last edited by

            @DustinB3403 said in Cannot SSH using public key:

            Technically the guide I see here is showing RSA key pairs and not dsa, even though the instructions say to use

            ssh-keygen -t dsa

            . . .

            This will create the following files 2 files;
            /home/scan_man/.ssh/new_id_rsa.pub  ===> Public Key
            /home/scan_man/.ssh/new_id_rsa  ===> Private Key
            

            Yeah those guides are fucked. This the second one I am following today and the second one that is completely fucked up.

            travisdh1T 1 Reply Last reply Reply Quote 1
            • travisdh1T
              travisdh1 @IRJ
              last edited by

              @IRJ said in Cannot SSH using public key:

              @DustinB3403 said in Cannot SSH using public key:

              Technically the guide I see here is showing RSA key pairs and not dsa, even though the instructions say to use

              ssh-keygen -t dsa

              . . .

              This will create the following files 2 files;
              /home/scan_man/.ssh/new_id_rsa.pub  ===> Public Key
              /home/scan_man/.ssh/new_id_rsa  ===> Private Key
              

              Yeah those guides are fucked. This the second one I am following today and the second one that is completely fucked up.

              /agree

              IRJI 1 Reply Last reply Reply Quote 0
              • IRJI
                IRJ @travisdh1
                last edited by

                @travisdh1 said in Cannot SSH using public key:

                @IRJ said in Cannot SSH using public key:

                @DustinB3403 said in Cannot SSH using public key:

                Technically the guide I see here is showing RSA key pairs and not dsa, even though the instructions say to use

                ssh-keygen -t dsa

                . . .

                This will create the following files 2 files;
                /home/scan_man/.ssh/new_id_rsa.pub  ===> Public Key
                /home/scan_man/.ssh/new_id_rsa  ===> Private Key
                

                Yeah those guides are fucked. This the second one I am following today and the second one that is completely fucked up.

                /agree

                I figured the first one out. I guess I should make guides here once I am done, because the interwebs does not have any good documentation for this and Tenable has really screwed up.

                1 Reply Last reply Reply Quote 1
                • IRJI
                  IRJ @travisdh1
                  last edited by

                  @travisdh1 said in Cannot SSH using public key:

                  @IRJ First off, generate the key as the user, just to make everything that much simpler. Use sudo if you have to.

                  sudo - scan_user keygen
                  

                  Then copy the public key wherever.

                  sudo - scan_user ssh-copy-id scan_user@wherever
                  

                  If those throw an error, try without the - (that tells sudo to fully load the scan_user profile.)

                  No mussing about with permissions, they are set coherently already.

                  As @DustinB3403 said, Nessus will have to support the encryption. If they don't support at least RSA, all these "security" things they tell you to do is not worth anything.

                  It should support RSA , and it looks like i should switch user to generate keys. I dont see anywhere to generate for another user.

                  DustinB3403D 1 Reply Last reply Reply Quote 0
                  • DustinB3403D
                    DustinB3403 @IRJ
                    last edited by

                    @IRJ Just login as the scan_user and then run the ssh-keygen process if you want to run it under that user account.

                    1 Reply Last reply Reply Quote 1
                    • DustinB3403D
                      DustinB3403
                      last edited by

                      Literally su scan_user
                      ssh-keygen -t rsa

                      IRJI 1 Reply Last reply Reply Quote 0
                      • IRJI
                        IRJ @DustinB3403
                        last edited by

                        @DustinB3403 said in Cannot SSH using public key:

                        Literally su scan_user
                        ssh-keygen -t rsa

                        yeah doing it now.

                        1 Reply Last reply Reply Quote 0
                        • IRJI
                          IRJ
                          last edited by

                          Still getting permission denied when trying to login even via ssh-copy-id

                          1 Reply Last reply Reply Quote 0
                          • IRJI
                            IRJ
                            last edited by

                            I want to throw something right now!!! This should be so basic!!! ugh

                            1 Reply Last reply Reply Quote 0
                            • DustinB3403D
                              DustinB3403
                              last edited by

                              @IRJ okay lets take a step back.

                              Can you ssh into this unit as scan_user ?

                              ssh [email protected] ?

                              IRJI 1 Reply Last reply Reply Quote 0
                              • IRJI
                                IRJ @DustinB3403
                                last edited by

                                @DustinB3403 said in Cannot SSH using public key:

                                @IRJ okay lets take a step back.

                                Can you ssh into this unit as scan_user ?

                                ssh [email protected] ?

                                I cannot right now because I have these lines in sshd

                                Match User scan_user
                                    PasswordAuthentication no
                                
                                DustinB3403D 1 Reply Last reply Reply Quote 0
                                • DustinB3403D
                                  DustinB3403 @IRJ
                                  last edited by DustinB3403

                                  @IRJ said in Cannot SSH using public key:

                                  @DustinB3403 said in Cannot SSH using public key:

                                  @IRJ okay lets take a step back.

                                  Can you ssh into this unit as scan_user ?

                                  ssh [email protected] ?

                                  I cannot right now because I have these lines in sshd

                                  Match User scan_user
                                      PasswordAuthentication no
                                  

                                  Then you would never be able to copy the key to this system. You need password auth first, which can be disabled once you have working keys.


                                  Unless you manually copy and paste the key to this system, which is stupid.

                                  Just enable passauth for the time, setup the key with ssh-copy-id and then turn off the passwordauth.

                                  IRJI 1 Reply Last reply Reply Quote 0
                                  • IRJI
                                    IRJ @DustinB3403
                                    last edited by

                                    @DustinB3403 said in Cannot SSH using public key:

                                    @IRJ said in Cannot SSH using public key:

                                    @DustinB3403 said in Cannot SSH using public key:

                                    @IRJ okay lets take a step back.

                                    Can you ssh into this unit as scan_user ?

                                    ssh [email protected] ?

                                    I cannot right now because I have these lines in sshd

                                    Match User scan_user
                                        PasswordAuthentication no
                                    

                                    Then you would never be able to copy the key to this system. You need password auth first, which can be disabled once you have working keys.

                                    Ok. I commented out restarted sshd and I was able to login with password.

                                    DustinB3403D 1 Reply Last reply Reply Quote 0
                                    • DustinB3403D
                                      DustinB3403 @IRJ
                                      last edited by

                                      @IRJ said in Cannot SSH using public key:

                                      @DustinB3403 said in Cannot SSH using public key:

                                      @IRJ said in Cannot SSH using public key:

                                      @DustinB3403 said in Cannot SSH using public key:

                                      @IRJ okay lets take a step back.

                                      Can you ssh into this unit as scan_user ?

                                      ssh [email protected] ?

                                      I cannot right now because I have these lines in sshd

                                      Match User scan_user
                                          PasswordAuthentication no
                                      

                                      Then you would never be able to copy the key to this system. You need password auth first, which can be disabled once you have working keys.

                                      Ok. I commented out restarted sshd and I was able to login with password.

                                      Okay, now perform the ssh-copy-id command.

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                                      • DustinB3403D
                                        DustinB3403
                                        last edited by

                                        @IRJ ?

                                        IRJI 1 Reply Last reply Reply Quote 1
                                        • IRJI
                                          IRJ @DustinB3403
                                          last edited by

                                          @DustinB3403 said in Cannot SSH using public key:

                                          @IRJ ?

                                          I finally got it working! I commented that out and it is now working. I was also able to turn off password authentication for that account.

                                          The issue was in my sshd_config

                                          AuthorizedKeysFile  %h/.ssh/authorized_keys
                                          
                                          1 Reply Last reply Reply Quote 0
                                          • IRJI
                                            IRJ
                                            last edited by

                                            Gonna have to do this on another server for a sanity check though lol

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