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    pfSense weak DH vuln found with Kali

    Scheduled Pinned Locked Moved General pfSense Questions
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    • johnpozJ Offline
      johnpoz LAYER 8 Global Moderator
      last edited by johnpoz

      Not sure what your running... I don't recall tweaking any of my httpd settings on pfsense... I can fire one up out of the box on vm and scan again with ssltest..

      But have no idea where your seeing dh that low

       Testing 370 ciphers via OpenSSL plus sockets against the server, ordered by encryption strength 
      
      Hexcode  Cipher Suite Name (OpenSSL)       KeyExch.   Encryption  Bits     Cipher Suite Name (IANA/RFC)
      -----------------------------------------------------------------------------------------------------------------------------
       xc030   ECDHE-RSA-AES256-GCM-SHA384       ECDH 256   AESGCM      256      TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384              
       xc028   ECDHE-RSA-AES256-SHA384           ECDH 256   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384              
       xc014   ECDHE-RSA-AES256-SHA              ECDH 256   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA                 
       x9f     DHE-RSA-AES256-GCM-SHA384         DH 4096    AESGCM      256      TLS_DHE_RSA_WITH_AES_256_GCM_SHA384                
       x6b     DHE-RSA-AES256-SHA256             DH 4096    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA256                
       x39     DHE-RSA-AES256-SHA                DH 4096    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA                   
       xc02f   ECDHE-RSA-AES128-GCM-SHA256       ECDH 256   AESGCM      128      TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256              
       x9e     DHE-RSA-AES128-GCM-SHA256         DH 4096    AESGCM      128      TLS_DHE_RSA_WITH_AES_128_GCM_SHA256             
      

      Just ran ssltest against pfsense and only see the cipers that do dh all at 4096

      Only thing that comes back with possible vuln is

      LUCKY13 (CVE-2013-0169), experimental     potentially VULNERABLE, uses cipher block chaining (CBC) ciphers with TLS. Check patches
      

      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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      • NogBadTheBadN Offline
        NogBadTheBad
        last edited by NogBadTheBad

        mac-pro:~ andy$ nmap --script ssl-dh-params.nse 172.16.0.1
        
        Starting Nmap 7.40 ( https://nmap.org ) at 2019-03-25 18:49 GMT
        Nmap scan report for pfsense (172.16.0.1)
        Host is up (0.0019s 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
        | ssl-dh-params: 
        |   VULNERABLE:
        |   Diffie-Hellman Key Exchange Insufficient Group Strength
        |     State: VULNERABLE
        |       Transport Layer Security (TLS) services that use Diffie-Hellman groups
        |       of insufficient strength, especially those using one of a few commonly
        |       shared groups, may be susceptible to passive eavesdropping attacks.
        |     Check results:
        |       WEAK DH GROUP 1
        |             Cipher Suite: TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA
        |             Modulus Type: Non-safe prime
        |             Modulus Source: RFC5114/1024-bit DSA group with 160-bit prime order subgroup
        |             Modulus Length: 1024
        |             Generator Length: 1024
        |             Public Key Length: 1024
        |     References:
        |_      https://weakdh.org
        
        Nmap done: 1 IP address (1 host up) scanned in 5.73 seconds
        mac-pro:~ andy$
        

        Just looked at my certs in keychain, they're all 2048

        Andy

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

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

          I will fire up a clean vm...

           Testing robust (perfect) forward secrecy, (P)FS -- omitting Null Authentication/Encryption, 3DES, RC4 
          
           PFS is offered (OK)          ECDHE-RSA-AES256-GCM-SHA384 ECDHE-RSA-AES256-SHA384 ECDHE-RSA-AES256-SHA DHE-RSA-AES256-GCM-SHA384 DHE-RSA-AES256-SHA256
                                        DHE-RSA-AES256-SHA ECDHE-RSA-AES128-GCM-SHA256 DHE-RSA-AES128-GCM-SHA256 
           Elliptic curves offered:     sect283k1 sect283r1 sect409k1 sect409r1 sect571k1 sect571r1 secp256k1 prime256v1 secp384r1 secp521r1 brainpoolP256r1 brainpoolP384r1 
                                        brainpoolP512r1 
           DH group offered:            Unknown DH group (4096 bits)
          

          What are you running on pfsense that listens on 8081?

          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

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

            @johnpoz @BBcan177

            Ah it's DNSBL.

            Hmmm disable DNSBL and its a pass.

            If I look at the cert and the key size is 2048.

            Screenshot 2019-03-25 at 19.14.03.png

            Andy

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

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

              Key size is not the same has DH size... Sorry but out of the box the DH is 4096..

              I just fired up a 2.4.4p1 clean VM... nothing more than clicking ok in the wizard and this is what the out of the box gui offers

               Testing 370 ciphers via OpenSSL plus sockets against the server, ordered by encryption strength 
              
              Hexcode  Cipher Suite Name (OpenSSL)       KeyExch.   Encryption  Bits     Cipher Suite Name (IANA/RFC)
              -----------------------------------------------------------------------------------------------------------------------------
               xc030   ECDHE-RSA-AES256-GCM-SHA384       ECDH 256   AESGCM      256      TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384              
               xc028   ECDHE-RSA-AES256-SHA384           ECDH 256   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384              
               xc014   ECDHE-RSA-AES256-SHA              ECDH 256   AES         256      TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA                 
               x9f     DHE-RSA-AES256-GCM-SHA384         DH 4096    AESGCM      256      TLS_DHE_RSA_WITH_AES_256_GCM_SHA384                
               x6b     DHE-RSA-AES256-SHA256             DH 4096    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA256                
               x39     DHE-RSA-AES256-SHA                DH 4096    AES         256      TLS_DHE_RSA_WITH_AES_256_CBC_SHA                   
               xc02f   ECDHE-RSA-AES128-GCM-SHA256       ECDH 256   AESGCM      128      TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256              
               x9e     DHE-RSA-AES128-GCM-SHA256         DH 4096    AESGCM      128      TLS_DHE_RSA_WITH_AES_128_GCM_SHA256                
              
              
               Running client simulations (HTTP) via sockets 
              
               Android 4.2.2                No connection
               Android 4.4.2                TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Android 5.0.0                TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256, 256 bit ECDH (P-256)
               Android 6.0                  TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256, 256 bit ECDH (P-256)
               Android 7.0                  TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Chrome 65 Win 7              TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Chrome 70 Win 10             TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Firefox 59 Win 7             TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Firefox 62 Win 7             TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               IE 6 XP                      No connection
               IE 7 Vista                   No connection
               IE 8 Win 7                   No connection
               IE 8 XP                      No connection
               IE 11 Win 7                  TLSv1.2 DHE-RSA-AES256-GCM-SHA384, 4096 bit DH  (ffdhe4096)
               IE 11 Win 8.1                TLSv1.2 DHE-RSA-AES256-GCM-SHA384, 4096 bit DH  (ffdhe4096)
               IE 11 Win Phone 8.1          TLSv1.2 ECDHE-RSA-AES256-SHA, 256 bit ECDH (P-256)
               IE 11 Win 10                 TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Edge 13 Win 10               TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Edge 13 Win Phone 10         TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Edge 15 Win 10               TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Opera 17 Win 7               TLSv1.2 ECDHE-RSA-AES256-SHA, 256 bit ECDH (P-256)
               Safari 9 iOS 9               TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Safari 9 OS X 10.11          TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Safari 10 OS X 10.12         TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Apple ATS 9 iOS 9            TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Tor 17.0.9 Win 7             No connection
               Java 6u45                    No connection
               Java 7u25                    No connection
               Java 8u161                   TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               Java 9.0.4                   TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               OpenSSL 1.0.1l               TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
               OpenSSL 1.0.2e               TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384, 256 bit ECDH (P-256)
              
              

              So not sure what he is testing, but it sure isn't pfsense gui..

              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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              • P Offline
                pooperman
                last edited by pooperman

                DNSBL is also running on my pfsense

                maybe kali checked the DNSBL cert?
                @johnpoz thanks for rechecking!

                NogBadTheBadN 1 Reply Last reply Reply Quote 0
                • NogBadTheBadN Offline
                  NogBadTheBad
                  last edited by

                  @pooperman is running pfblocker as well.

                  https://forum.netgate.com/topic/141220/pfblockerng-very-slow-at-dns

                  Andy

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

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                  • NogBadTheBadN Offline
                    NogBadTheBad @pooperman
                    last edited by

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

                    DNSBL is also running on my pfsense

                    maybe kali checked the DNSBL cert?
                    @johnpoz thanks for rechecking!

                    Yup stop DNSBL and you'll get a pass.

                    Andy

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

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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)?

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                          • 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

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                            • 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

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