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    Two factor authentication for openVPN in pfsense

    Scheduled Pinned Locked Moved OpenVPN
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    • DerelictD
      Derelict LAYER 8 Netgate
      last edited by

      Since I authenticate to a radius server already I just added a duo proxy to a VM that's always running.

      www.duosecurity.com

      My users can't handle "technical" things like appending an OTP to their password but they can wait for their phone to buzz and manage to tap "Accept."

      And what I really like about it is Duo will support EVERYTHING that supports RADIUS (or LDAP/AD) with no reliance on the product supporting your chosen 2FA solution, other than the ability to increase the authentication timeout to allow the user time to click accept. You just point the device at the Duo proxy instead of your normal authentication server.

      Chattanooga, Tennessee, USA
      A comprehensive network diagram is worth 10,000 words and 15 conference calls.
      DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
      Do Not Chat For Help! NO_WAN_EGRESS(TM)

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      • F
        FlashEngineer
        last edited by

        I have an account setup for duo, but how do I integrate this into pfsense's openvpn or radius as I'm authentication with certificate + user/pw in radius as well.

        @Derelict:

        Since I authenticate to a radius server already I just added a duo proxy to a VM that's always running.

        www.duosecurity.com

        My users can't handle "technical" things like appending an OTP to their password but they can wait for their phone to buzz and manage to tap "Accept."

        And what I really like about it is Duo will support EVERYTHING that supports RADIUS (or LDAP/AD) with no reliance on the product supporting your chosen 2FA solution, other than the ability to increase the authentication timeout to allow the user time to click accept. You just point the device at the Duo proxy instead of your normal authentication server.

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        • DerelictD
          Derelict LAYER 8 Netgate
          last edited by

          Point pfSense RADIUS at the duo radius proxy server you have to set up and point the proxy at your RADIUS server.

          Chattanooga, Tennessee, USA
          A comprehensive network diagram is worth 10,000 words and 15 conference calls.
          DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
          Do Not Chat For Help! NO_WAN_EGRESS(TM)

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          • F
            FlashEngineer
            last edited by

            @Derelict:

            Point pfSense RADIUS at the duo radius proxy server you have to set up and point the proxy at your RADIUS server.

            Ok so in user manager create another connection to the DUO proxy server and set that as authentication in the OpenVPN server ?

            Then in the duoauthproxy.cfg, there's [radius_client] and [raidus_server_auto]

            Which do I put in those?

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            • DerelictD
              Derelict LAYER 8 Netgate
              last edited by

              Lots of documentation on the Duo site but ok:

              authproxy.cfg

              [ad_client]
              host=
              service_account_username=
              service_account_password=
              search_dn=

              This is the RADIUS Server

              This proxy must be configured as a client on the server

              [radius_client]
              host=192.168.223.17
              secret=*

              [radius_server_auto]
              ikey=*
              skey=*
              api_host=api-xxx.duosecurity.com

              This is pfSense

              Set this proxy as the authentication server

              Set OpenVPN to use it.

              radius_ip_1=192.168.223.1
              radius_secret_1=*

              This is another RADIUS client

              radius_ip_2=192.168.223.219
              radius_secret_2=*
              failmode=safe
              client=radius_client
              port=1812

              Chattanooga, Tennessee, USA
              A comprehensive network diagram is worth 10,000 words and 15 conference calls.
              DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
              Do Not Chat For Help! NO_WAN_EGRESS(TM)

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              • F
                FlashEngineer
                last edited by

                Yes I read the docs but I wasn't understanding what it means..

                So basically radius client = the IP address of the duo proxy (VM in your case) is hosted on.

                The radius server auto is the pfsense's radius server.

                Is this how it works? :

                1.  OpenVPN will use the duoproxy (located on your VM) as radius auth
                2.  The DUO proxy will contact DUO server for push
                3.  DUO proxy will relay back the primary auth raidus to pfsense's (for username/pw in pfsense' freeradius)

                that correct?

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                • DerelictD
                  Derelict LAYER 8 Netgate
                  last edited by

                  • pfSense asks the proxy if username/password is correct

                  • The proxy asks the RADIUS server if the username and password are correct

                  • If no, the proxy sends an Access-Reject back to pfSense

                  • If yes, the proxy starts a duo authentication with the API server

                  • If it fails, the proxy sends an Access-Reject to pfSense (this is why you need a longer timeout in the pfSense config - time for all this to happen. I use 60s)

                  • If successful, the proxy sends Access-Accept to pfSense

                  Note that you are free to have a RADIUS server configured in System > User Manager, Servers that points to the RADIUS server and one that points at the Duo proxy. Then you can pick and choose which services must two-factor and which don't by selecting the appropriate authentication server in that service. You can test them in Diagnostics > Authentication.

                  Chattanooga, Tennessee, USA
                  A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                  DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                  Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                  • johnpozJ
                    johnpoz LAYER 8 Global Moderator
                    last edited by

                    So what your after is multifactor, not just 2 factor because by definition if your auth requires something you have and something you know you have your 2 factors.

                    The cert you have to have on your machine, and the password to said cert and or login would mean your already doing 3 factor.  Something you have and 2 things you know.  The cert is the thing you have, the password to said cert would be the 1 thing you know, and the username and password to auth to openvpn is the 2nd thing you know.

                    How is ssl/tls+user auth not meet 2 factor??

                    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 2.8, 24.11

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                    • DerelictD
                      Derelict LAYER 8 Netgate
                      last edited by

                      picky picky but correct. This would be two things he has (the private key and the duo phone) and one thing he knows (the username/password). And in my case the Duo app requires me to enter the phone passcode or TouchID in most cases, so there is another known factor or an are factor.

                      Chattanooga, Tennessee, USA
                      A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                      DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                      Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                      • johnpozJ
                        johnpoz LAYER 8 Global Moderator
                        last edited by

                        yeah you can go to many many factors.. Duplication of things is not always considered another factor

                        Normally you can go to 3 factor
                        something you have
                        something you know
                        something you are.

                        My point is he already has 2 factors with the cert and the password..  Adding another just makes it harder to log in, for what possible reason?  Is this a gov facility?  There is being secure and taking steps to be secure and then there is just overhead and complication for no extra security.

                        To me the OTP thing, or use of some token that changes code ever so many seconds, etc.  is just plain PITA..  And unless your line of work justifies the extra effort its just making it harder to get anything done.

                        Just my 2 cents on the whole matter… While I think such methods of auth are pretty cool, and fun to setup - actual use of them are PITA..

                        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 2.8, 24.11

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                        • F
                          FlashEngineer
                          last edited by

                          Thanks, this is working now as when I login to OpenVPN it pushes the DUO notification to click to accept, which is good enough for my uses, rather than enter a code which is annoying.

                          One thing I don't understand is, in the duo config on my duo proxy, both sections I had to put my pfSense ip address as the radius.  Does that make sense?  It works though…

                          @Derelict:

                          • pfSense asks the proxy if username/password is correct

                          • The proxy asks the RADIUS server if the username and password are correct

                          • If no, the proxy sends an Access-Reject back to pfSense

                          • If yes, the proxy starts a duo authentication with the API server

                          • If it fails, the proxy sends an Access-Reject to pfSense (this is why you need a longer timeout in the pfSense config - time for all this to happen. I use 60s)

                          • If successful, the proxy sends Access-Accept to pfSense

                          Note that you are free to have a RADIUS server configured in System > User Manager, Servers that points to the RADIUS server and one that points at the Duo proxy. Then you can pick and choose which services must two-factor and which don't by selecting the appropriate authentication server in that service. You can test them in Diagnostics > Authentication.

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                          • DerelictD
                            Derelict LAYER 8 Netgate
                            last edited by

                            The comments in the config file I posted are self-explanatory. Post yours so I can see what you're talking about.

                            The one in radius_client should be the actual RADIUS server that holds the usernames and passwords.

                            The one in radius_ip_1 is pfSense which is really a RADIUS client to the proxy (something that asks the proxy to do an authentication).

                            Chattanooga, Tennessee, USA
                            A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                            DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                            Do Not Chat For Help! NO_WAN_EGRESS(TM)

                            1 Reply Last reply Reply Quote 0
                            • F
                              FlashEngineer
                              last edited by

                              @Derelict:

                              The comments in the config file I posted are self-explanatory. Post yours so I can see what you're talking about.

                              The one in radius_client should be the actual RADIUS server that holds the usernames and passwords.

                              The one in radius_ip_1 is pfSense which is really a RADIUS client to the proxy (something that asks the proxy to do an authentication).

                              Here is my config:

                              [radius_client]
                              host=10.10.10.1
                              secret=

                              [radius_server_auto]
                              ikey=
                              skey=
                              api_host=
                              radius_ip_1=10.10.10.1
                              radius_secret_1=
                              failmode=safe
                              client=radius_client
                              port=1812

                              Both IP are pointing to pfsense box's FreeRadius server.

                              Well since I'm hosting radius with pfsense, which has same IP, I guess they are both the same?

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                              • F
                                FlashEngineer
                                last edited by

                                @johnpoz:

                                yeah you can go to many many factors.. Duplication of things is not always considered another factor

                                Normally you can go to 3 factor
                                something you have
                                something you know
                                something you are.

                                My point is he already has 2 factors with the cert and the password..  Adding another just makes it harder to log in, for what possible reason?  Is this a gov facility?  There is being secure and taking steps to be secure and then there is just overhead and complication for no extra security.

                                To me the OTP thing, or use of some token that changes code ever so many seconds, etc.  is just plain PITA..  And unless your line of work justifies the extra effort its just making it harder to get anything done.

                                Just my 2 cents on the whole matter… While I think such methods of auth are pretty cool, and fun to setup - actual use of them are PITA..

                                If it's possible and easily done, why not?  I'm really the only one that's logging into my network and I rather have another level of authentication.  Plus the DUO is a good compromise, all you do is click vs the token codes like google authentication which you have to enter a code.  I don't see how that would hinder any real production environment as my company I work for actually uses DUO to authenticate when connecting to VPN from remote.

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                                • DerelictD
                                  Derelict LAYER 8 Netgate
                                  last edited by

                                  They're not. One is allowing pfSense to send requests to the proxy and the other is asking pfSense's RADIUS server to authenticate.

                                  Mine are different because my RADIUS server isn't pfSense. It's Mac OS X Server.

                                  Chattanooga, Tennessee, USA
                                  A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                                  DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                                  Do Not Chat For Help! NO_WAN_EGRESS(TM)

                                  1 Reply Last reply Reply Quote 0
                                  • F
                                    FlashEngineer
                                    last edited by

                                    @Derelict:

                                    They're not. One is allowing pfSense to send requests to the proxy and the other is asking pfSense's RADIUS server to authenticate.

                                    Mine are different because my RADIUS server isn't pfSense. It's Mac OS X Server.

                                    I think I understand… I guess I could set a different IP address for the RADIUS on pfSense so it's more obvious.  Since right now the radius server interface is same IP as pfSense.

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                                    • DerelictD
                                      Derelict LAYER 8 Netgate
                                      last edited by

                                      If both RADIUS client and server on the same node don't over-think it. If you make pfSense do everything, then everything is going to have the same IP address.

                                      I do it this way so everyone's login information is the same. Change their Mac login password, and their VPN (and mail, calendar, etc) password changes. People could enable AD RADIUS and do the same thing. Or use the LDAP Proxy. (I prefer RADIUS because it's not MS-centric).

                                      Chattanooga, Tennessee, USA
                                      A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                                      DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                                      Do Not Chat For Help! NO_WAN_EGRESS(TM)

                                      1 Reply Last reply Reply Quote 0
                                      • J
                                        Jamerson
                                        last edited by

                                        i was wondering if there some kind of token software for the android of iOS to allow 3 steps auth.
                                        already using cert + username + password auth.

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                                        • DerelictD
                                          Derelict LAYER 8 Netgate
                                          last edited by

                                          Yeah. Duo as has been discussed works on android. One ought to be able to roll a RADIUS proxy for google authenticator, etc. Not sure about it being running on pfSense. That would be a question for the FreeRADIUS package maintainers.

                                          Chattanooga, Tennessee, USA
                                          A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                                          DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                                          Do Not Chat For Help! NO_WAN_EGRESS(TM)

                                          1 Reply Last reply Reply Quote 0
                                          • J
                                            jkmuk
                                            last edited by

                                            @Derelict:

                                            • pfSense asks the proxy if username/password is correct

                                            • The proxy asks the RADIUS server if the username and password are correct

                                            • If no, the proxy sends an Access-Reject back to pfSense

                                            • If yes, the proxy starts a duo authentication with the API server

                                            • If it fails, the proxy sends an Access-Reject to pfSense (this is why you need a longer timeout in the pfSense config - time for all this to happen. I use 60s)

                                            • If successful, the proxy sends Access-Accept to pfSense

                                            Note that you are free to have a RADIUS server configured in System > User Manager, Servers that points to the RADIUS server and one that points at the Duo proxy. Then you can pick and choose which services must two-factor and which don't by selecting the appropriate authentication server in that service. You can test them in Diagnostics > Authentication.

                                            A sample configuration based on the above clear explanation for anyone who wants it

                                            [radius_client]
                                            #Step 2: Contact the below IP (Primary authentication server) using the below secret to validate user name and password provided 
                                            host=10.xx.xx.1
                                            secret=secretonpfsense
                                            
                                            [radius_server_auto]
                                            #Step 4: Contact Duo API (Second factor authentication server) using the below details to approve/reject access request 
                                            ikey=DIXXXXXXXXXXXXXXXX
                                            skey=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
                                            api_host=api-xxxxxxxxx.duosecurity.com
                                            
                                            #Step 1: Expect a request from the below IP (pfsense box in this instance)  providing the below secret seeking authentication
                                            radius_ip_1=10.xx.xx.1
                                            radius_secret_1=secretonproxy
                                            
                                            failmode=safe
                                            client=radius_client
                                            port=1812
                                            
                                            
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