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    pfSense weak DH vuln found with Kali

    Scheduled Pinned Locked Moved General pfSense Questions
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    • P Offline
      pooperman
      last edited by

      just to get it right, DNSBL shall just redirect unwanted "data".
      In order to keep integrity, it is using a cert and this cert is having insuffizient DH strength?

      If so, according to my understanding there is actually no problem. In case someone breaks encryption it will just get all the rubbish that I do not want, correct?

      1 Reply Last reply Reply Quote 0
      • johnpozJ Offline
        johnpoz LAYER 8 Global Moderator
        last edited by

        @pooperman said in pfSense weak DH vuln found with Kali:

        DNSBL

        ask @BBcan177 maybe he can shed some light on what his package is doing... If its serving up something on https, then it should be using current best practices to do so..

        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

        P 1 Reply Last reply Reply Quote 1
        • P Offline
          pooperman @johnpoz
          last edited by

          @johnpoz said in pfSense weak DH vuln found with Kali:

          @pooperman said in pfSense weak DH vuln found with Kali:

          DNSBL

          ask @BBcan177 maybe he can shed some light on what his package is doing... If its serving up something on https, then it should be using current best practices to do so..

          thanks for support!

          will an @ and the name triggers something at the users interface in this forum ie. get an altert?
          Or shall i contact him directly?

          may I ask how and where you tested the DH key size (6th post)?

          1 Reply Last reply Reply Quote 0
          • johnpozJ Offline
            johnpoz LAYER 8 Global Moderator
            last edited by

            The @ should send him notification of this post.

            The script I use to test ssl stuff is here
            https://github.com/drwetter/testssl.sh

            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

            1 Reply Last reply Reply Quote 1
            • NogBadTheBadN Offline
              NogBadTheBad
              last edited by

              He not been online for 11 days, I've made a post on reddit linking here.

              Andy

              1 x Netgate SG-4860 - 3 x Linksys LGS308P - 1 x Aruba InstantOn AP22

              BBcan177B 1 Reply Last reply Reply Quote 1
              • BBcan177B Offline
                BBcan177 Moderator @NogBadTheBad
                last edited by

                @NogBadTheBad

                The function that generates the cert is here:
                https://github.com/pfsense/FreeBSD-ports/blob/devel/net/pfSense-pkg-pfBlockerNG-devel/files/usr/local/pkg/pfblockerng/pfblockerng.inc#L1024-L1049

                I don't think its necessary for what the DNSBL server is serving, but you can change the settings in the code, delete the cert and then Force Update for the cert to be re-created with the new settings. If you test it successfully, let me know and I will change the code in the next release.

                /var/unbound/dnsbl_cert.pem
                

                "Experience is something you don't get until just after you need it."

                Website: http://pfBlockerNG.com
                Twitter: @BBcan177  #pfBlockerNG
                Reddit: https://www.reddit.com/r/pfBlockerNG/new/

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                • johnpozJ Offline
                  johnpoz LAYER 8 Global Moderator
                  last edited by johnpoz

                  Lets be clear is not the cert that the problem
                  https://docs.netgate.com/pfsense/en/latest/certificates/dh-parameters.html

                  What is pfblocker using that would be different than what the web gui is using?

                  We are not sure what they are actually hitting when they are testing.. All I can tell you is not the pfsense web gui.

                  So DNSBL listens on port what for SSL, you set this? 8443? How exactly does it serve this up where would it get its DH-parameters from? See the link above.

                  [2.4.4-RELEASE][admin@sg4860.local.lan]/etc: ls -la dh*
                  -rw-r--r--  1 root  wheel   245 Nov 17  2017 dh-parameters.1024
                  -rw-r--r--  1 root  wheel   424 Nov 17  2017 dh-parameters.2048
                  -rw-r--r--  1 root  wheel   595 Oct  4 08:37 dh-parameters.3072
                  -rw-r--r--  1 root  wheel   769 Nov 17  2017 dh-parameters.4096
                  -rw-r--r--  1 root  wheel  1115 Oct  4 08:37 dh-parameters.6144
                  -rw-r--r--  1 root  wheel  1464 Oct  4 08:37 dh-parameters.8192
                  

                  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

                  BBcan177B 1 Reply Last reply Reply Quote 0
                  • BBcan177B Offline
                    BBcan177 Moderator @johnpoz
                    last edited by

                    @johnpoz

                    It uses lighttpd not nginx that is used by the pfSense gui:
                    https://redmine.lighttpd.net/projects/lighttpd/wiki/Docs_SSL

                    Would have to add the DH params to the dnsbl lighttpd conf file:
                    var/unbound/pfb_dnsbl_lighty.conf

                    That file is auto created so changes will be overwritten. Don't have time to look at it atm.

                    "Experience is something you don't get until just after you need it."

                    Website: http://pfBlockerNG.com
                    Twitter: @BBcan177  #pfBlockerNG
                    Reddit: https://www.reddit.com/r/pfBlockerNG/new/

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                    • johnpozJ Offline
                      johnpoz LAYER 8 Global Moderator
                      last edited by johnpoz

                      Yeah my guess but can not seem to find it in the conf is this
                      ssl.dh-file="{path to dhparams.pem}"

                      So not sure what its using if not called out?

                      To be honest this isn't really that big of deal - other than people doing such scans and thinking the problem is pfsense ;) hehehe

                      I set up pfSense and I was checking for general vulnerabilities.

                      No where did he mention installed "optional" packages xyz, and abc, etc..

                      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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                      • stephenw10S Offline
                        stephenw10 Netgate Administrator
                        last edited by

                        Well to be fair he did discover something that should probably be updated, if only to prevent false positives as you say.

                        Steve

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                        • BBcan177B Offline
                          BBcan177 Moderator
                          last edited by BBcan177

                          Edit the file (for pfBlockerNG-devel):

                          /usr/local/pkg/pfblockerng/pfblockerng.inc
                          

                          And add the 6 "+" lines as depicted in this screenshot:
                          lighttpd.JPG

                                  $SERVER["socket"] == "127.0.0.1:8443" {
                                          ssl.engine      = "enable"
                                          ssl.pemfile     = "/var/unbound/dnsbl_cert.pem"
                                          ssl.dh-file       = "/etc/dh-parameters.4096"
                                          ssl.cipher-list  = "EECDH+AESGCM:EDH+AESGCM:AES128+EECDH:AES128+EDH"
                                          ssl.ec-curve    = "secp384r1"
                                  }
                          
                                  $SERVER["socket"] == "10.10.10.2:443" {
                                          ssl.engine      = "enable"
                                          ssl.pemfile     = "/var/unbound/dnsbl_cert.pem"
                                          ssl.dh-file       = "/etc/dh-parameters.4096"
                                          ssl.cipher-list  = "EECDH+AESGCM:EDH+AESGCM:AES128+EECDH:AES128+EDH"
                                          ssl.ec-curve    = "secp384r1"
                                  }
                          

                          Stop the pfb_dnsbl Service
                          Then remove the existing lighttpd config file.

                          rm /var/unbound/pfb_dnsbl_lighty.conf
                          

                          Then Force Update for it to be re-created with the new changes.
                          Please post back after running your vulnerability scans.
                          Thanks!

                          "Experience is something you don't get until just after you need it."

                          Website: http://pfBlockerNG.com
                          Twitter: @BBcan177  #pfBlockerNG
                          Reddit: https://www.reddit.com/r/pfBlockerNG/new/

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                          • johnpozJ Offline
                            johnpoz LAYER 8 Global Moderator
                            last edited by johnpoz

                            As always @BBcan177 your johnny on the spot!

                            And also took the time to update the cipher list and curve.. Nice!

                            @stephenw10 agree its a good find, even if found in a round about way.

                            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

                            1 Reply Last reply Reply Quote 1
                            • NogBadTheBadN Offline
                              NogBadTheBad
                              last edited by

                              @BBcan177 said in pfSense weak DH vuln found with Kali:

                              rm /var/unbound/pfb_dnsbl_lighty.conf

                              mac-pro:~ andy$ nmap --script ssl-dh-params.nse 172.16.0.1

                              Starting Nmap 7.40 ( https://nmap.org ) at 2019-03-26 09:27 GMT
                              Nmap scan report for pfsense (172.16.0.1)
                              Host is up (0.0018s latency).
                              Not shown: 995 filtered ports
                              PORT STATE SERVICE
                              22/tcp open ssh
                              53/tcp open domain
                              443/tcp open https
                              8081/tcp open blackice-icecap
                              8443/tcp open https-alt

                              Nmap done: 1 IP address (1 host up) scanned in 6.40 seconds
                              mac-pro:~ andy$

                              Yea that fixed it :)

                              Andy

                              1 x Netgate SG-4860 - 3 x Linksys LGS308P - 1 x Aruba InstantOn AP22

                              BBcan177B 1 Reply Last reply Reply Quote 0
                              • BBcan177B Offline
                                BBcan177 Moderator @NogBadTheBad
                                last edited by

                                @NogBadTheBad said in pfSense weak DH vuln found with Kali:

                                Yea that fixed it :)

                                Thanks for testing... Will add it to the next release...

                                "Experience is something you don't get until just after you need it."

                                Website: http://pfBlockerNG.com
                                Twitter: @BBcan177  #pfBlockerNG
                                Reddit: https://www.reddit.com/r/pfBlockerNG/new/

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                                • P Offline
                                  pooperman
                                  last edited by

                                  many thanks for checking /helping and fixing it, to all.
                                  Really appreciated!

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