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SSH: Couldn't agree a key algorithm (available: curve25519-sha256@libssh.org)

Problems Installing or Upgrading pfSense Software
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  • C
    chrcoluk
    last edited by Jan 6, 2017, 3:52 PM Jan 6, 2017, 3:47 PM

    @johnpoz:

    yeah the issue I am having is with securecrt, you would think they would enabled chacha20 but not yet.. they just recently added ed25519..

    But the dev version of putty has had both for quite some time.

    That product director has driven me up the wall, her name maureen I think.

    About a year or so ago I requested what I consider easy to adopt changes.

    Support for chacha20
    Support for gcm ciphers

    To this day still no support.

    Yet they have managed to do updates that affect the GUI design and some other stuff.

    Seems their priority is making the program look pretty but not security enhancements.

    https://forums.vandyke.com/showthread.php?t=12209
    https://www.vandyke.com/products/securecrt/history.txt
    https://s2-forums.vandyke.com/showthread.php?p=46666

    very frustrating.

    pfSense CE 2.7.2

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    • J
      johnpoz LAYER 8 Global Moderator
      last edited by Jan 6, 2017, 5:28 PM

      Yeah your right her name is Maureen from the thread.. Her last excuse

      We have a fairly small develpment team and it can be a challenge to balance implementing new features, fixing bugs, and making sure our applications run on the latest version of the supported platforms.

      My answer to that was putty has 1 guy coding ;)  And it has had support pretty much since its been available ;)

      I told her their product is dead to me.. Its completely useless if its not going to support modern ciphers and algo's.. The closest they have come is back in Jan of 2016 they added ECDSA and Ed25519 keys

      An intelligent man is sometimes forced to be drunk to spend time with his fools
      If you get confused: Listen to the Music Play
      Please don't Chat/PM me for help, unless mod related
      SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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      • D
        doktornotor Banned
        last edited by Jan 7, 2017, 12:10 PM

        For putty, really use the daily builds ONLY. ECDSA and Ed25519 is there as well. The stable release is not usable.

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        • J
          johnpoz LAYER 8 Global Moderator
          last edited by Jan 7, 2017, 3:16 PM

          Yeah I use the dev bulds.. But as of late I just use kitty which is a fork of putty that supports everything as of a few updates back.  Or I just use the windows build of openssh.. This is really the easiest way to know for sure your going to have full support of all the ciphers and algo's that openssh is using.

          https://www.mls-software.com/opensshd.html

          An intelligent man is sometimes forced to be drunk to spend time with his fools
          If you get confused: Listen to the Music Play
          Please don't Chat/PM me for help, unless mod related
          SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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          • J
            jimp Rebel Alliance Developer Netgate
            last edited by Jan 17, 2017, 11:13 PM

            Good news, ChaCha20 is coming to SecureCRT

            You previously requested support for the ChaCha20-Poly1305 cipher for SSH2
            sessions.  This has been implemented in a pre-beta version of SecureCRT and SecureFX.

            If you would be interested in trying it, please let me know which product(s) and
            platform(s) you need.

            Products:

            SecureCRT
            SecureCRT and SecureFX

            Platforms:

            Windows (64-bit)
            Windows (32-bit)
            Mac OS X (10.11 and later)
            Linux (Ubuntu 16.x, 64-bit)
            Linux (Ubuntu 16.x, 32-bit)
            Linux (Ubuntu 14.x and 15.x, 64-bit)
            Linux (Ubuntu 14.x and 15.x, 32-bit)
            Linux (RHEL 7.0)

            Remember: Upvote with the 👍 button for any user/post you find to be helpful, informative, or deserving of recognition!

            Need help fast? Netgate Global Support!

            Do not Chat/PM for help!

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            • J
              johnpoz LAYER 8 Global Moderator
              last edited by Jan 19, 2017, 1:25 PM

              Yeah I just emailed her, says on my thread to contact her for access to the prebeta ;)

              An intelligent man is sometimes forced to be drunk to spend time with his fools
              If you get confused: Listen to the Music Play
              Please don't Chat/PM me for help, unless mod related
              SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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              • C
                chrcoluk
                last edited by Jan 20, 2017, 12:48 AM

                yeah she emailed me about it some days back, no GCM still but at least CHACHA is something.

                pfSense CE 2.7.2

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                • J
                  johnpoz LAYER 8 Global Moderator
                  last edited by Jan 20, 2017, 11:32 AM

                  So got the new secure beta.. And finally

                  [LOCAL] : Available Remote Send Ciphers = chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
                  [LOCAL] : Selected Send Cipher = chacha20-poly1305@openssh.com
                  [LOCAL] : Available Remote Recv Ciphers = chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
                  [LOCAL] : Selected Recv Cipher = chacha20-poly1305@openssh.com

                  Now they just need to add GCM ;)

                  An intelligent man is sometimes forced to be drunk to spend time with his fools
                  If you get confused: Listen to the Music Play
                  Please don't Chat/PM me for help, unless mod related
                  SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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                  • R
                    riahc3 Banned
                    last edited by Apr 20, 2017, 9:03 AM

                    @jimp:

                    FYI- We disabled some older, weaker, ssh key exchange algorithms. It won't be uncommon to find some older programs that use ssh directly or via things like libssh, that will need to be updated.

                    How do you reenable them?

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                    • J
                      johnpoz LAYER 8 Global Moderator
                      last edited by Apr 20, 2017, 9:34 AM

                      Why would you need to re-enable them.. They have been disabled for a reason, ie not secure.. Update your client is the correct fix here..

                      An intelligent man is sometimes forced to be drunk to spend time with his fools
                      If you get confused: Listen to the Music Play
                      Please don't Chat/PM me for help, unless mod related
                      SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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                      • R
                        riahc3 Banned
                        last edited by Apr 20, 2017, 9:51 AM Apr 20, 2017, 9:47 AM

                        @johnpoz:

                        Why would you need to re-enable them.. They have been disabled for a reason, ie not secure.. Update your client is the correct fix here..

                        Thats awesome.

                        How do you reenable them?

                        (For the record, yes, I am fully aware that many companies in 2016-2017, made SHA1 deprecated)

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                        • K
                          kpa
                          last edited by Apr 20, 2017, 9:53 AM

                          You re-enable them by rolling your own custom version of pfSense where you enable them in the openssh configuration. Oh and forget any official support if you follow that route.

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                          • R
                            riahc3 Banned
                            last edited by Apr 20, 2017, 9:58 AM

                            @kpa:

                            You re-enable them by rolling your own custom version of pfSense where you enable them in the openssh configuration. Oh and forget any official support if you follow that route.

                            No.

                            From the posts in this thread, they were disabled not removed (ala PPTP). They should be able to be enabled (under your own responsability)

                            The issue for example is that PPTP was warned several months in advance that it was going to get removed. Maybe I missed it for SHA1 but…

                            The point is that this thread only talks about it is disabled, not removed so...

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                            • J
                              johnpoz LAYER 8 Global Moderator
                              last edited by Apr 20, 2017, 10:39 AM Apr 20, 2017, 10:32 AM

                              "How do you reenable them?"

                              You edit your sshd_conf to use the what you want.. But again I am going to stress they were disabled for a REASON!!!

                              
                              [2.4.0-BETA][root@pfsense.local.lan]/etc/ssh: cat sshd_config 
                              # This file is automatically generated at startup
                              KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
                              Port 22
                              Protocol 2
                              HostKey /etc/ssh/ssh_host_rsa_key
                              HostKey /etc/ssh/ssh_host_ed25519_key
                              Compression yes
                              ClientAliveInterval 30
                              PermitRootLogin yes
                              # Login via Key only
                              ChallengeResponseAuthentication no
                              PasswordAuthentication no
                              PubkeyAuthentication yes
                              UsePAM no
                              UseDNS no
                              LoginGraceTime 30s
                              VersionAddendum none
                              X11Forwarding no
                              Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
                              MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-ripemd160-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160,umac-128@openssh.com
                              # override default of no subsystems
                              Subsystem       sftp    /usr/libexec/sftp-server
                              
                              

                              Notice the part that says this file created at startup.. So you would have to edit sshd script that does the creation.  Or you could use the sshd_extra file pretty sure..

                              I can not stress this enough - do not lower the security of your sshd, up the security of the client your using to access it.  Putty is FREE it works just fine, they have a securecrt client closed beta you can get that supports the chacha stuff.  You can use just the mls windows version of openssh, which is what I use all the time.. also FREE

                              You should never lower your security to "make something work"…  This is just bad security 101..

                              What I did notice from this thread since I connected in with ssh -v into pfsense is they are behind on their ssh.. they are running 7.2 while 7.5 is current.

                              debug1: Local version string SSH-2.0-OpenSSH_7.5
                              debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2
                              debug1: match: OpenSSH_7.2 pat OpenSSH* compat 0x04000000

                              An intelligent man is sometimes forced to be drunk to spend time with his fools
                              If you get confused: Listen to the Music Play
                              Please don't Chat/PM me for help, unless mod related
                              SG-4860 24.11 | Lab VMs 2.7.2, 24.11

                              1 Reply Last reply Reply Quote 0
                              • R
                                riahc3 Banned
                                last edited by Apr 20, 2017, 11:18 AM

                                @johnpoz:

                                "How do you reenable them?"

                                You edit your sshd_conf to use the what you want.. But again I am going to stress they were disabled for a REASON!!!

                                
                                [2.4.0-BETA][root@pfsense.local.lan]/etc/ssh: cat sshd_config 
                                # This file is automatically generated at startup
                                KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
                                Port 22
                                Protocol 2
                                HostKey /etc/ssh/ssh_host_rsa_key
                                HostKey /etc/ssh/ssh_host_ed25519_key
                                Compression yes
                                ClientAliveInterval 30
                                PermitRootLogin yes
                                # Login via Key only
                                ChallengeResponseAuthentication no
                                PasswordAuthentication no
                                PubkeyAuthentication yes
                                UsePAM no
                                UseDNS no
                                LoginGraceTime 30s
                                VersionAddendum none
                                X11Forwarding no
                                Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
                                MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-ripemd160-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160,umac-128@openssh.com
                                # override default of no subsystems
                                Subsystem       sftp    /usr/libexec/sftp-server
                                
                                

                                Notice the part that says this file created at startup.. So you would have to edit sshd script that does the creation.  Or you could use the sshd_extra file pretty sure..

                                I can not stress this enough - do not lower the security of your sshd, up the security of the client your using to access it.  Putty is FREE it works just fine, they have a securecrt client closed beta you can get that supports the chacha stuff.  You can use just the mls windows version of openssh, which is what I use all the time.. also FREE

                                You should never lower your security to "make something work"…  This is just bad security 101..

                                What I did notice from this thread since I connected in with ssh -v into pfsense is they are behind on their ssh.. they are running 7.2 while 7.5 is current.

                                debug1: Local version string SSH-2.0-OpenSSH_7.5
                                debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2
                                debug1: match: OpenSSH_7.2 pat OpenSSH* compat 0x04000000

                                Quoted in case of removal.

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                                • R
                                  riahc3 Banned
                                  last edited by Apr 20, 2017, 11:22 AM

                                  @johnpoz:

                                  I can not stress this enough - do not lower the security of your sshd, up the security of the client your using to access it.  Putty is FREE it works just fine, they have a securecrt client closed beta you can get that supports the chacha stuff.  You can use just the mls windows version of openssh, which is what I use all the time.. also FREE

                                  You should never lower your security to "make something work"…  This is just bad security 101..

                                  Even though this is not my case why I asked how to enable it again and while I agree with you, you cannot have 1000 clients waiting to be updated and/or people that use older clients where there isnt development anymore, suddenly stop working. You need a solution now. That quickest solution (as much as a bandaid it is) is to enable the older standard (which is really irrelevent when the servers are internal non public facing and/or you have monitoring on your systems)

                                  When you make sure that all clients are updated and compatible, THEN and ONLY then, can it be re disabled and use the newer and safer standard.

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                                  • J
                                    jimp Rebel Alliance Developer Netgate
                                    last edited by Apr 20, 2017, 11:40 AM

                                    You re-enable them the same way you revert any change you don't want. Find the commits that made the change and revert them or manually change them back the way they were.

                                    None of that banter belongs in this thread. Locking.

                                    Remember: Upvote with the 👍 button for any user/post you find to be helpful, informative, or deserving of recognition!

                                    Need help fast? Netgate Global Support!

                                    Do not Chat/PM for help!

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