Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    pfSense weak DH vuln found with Kali

    Scheduled Pinned Locked Moved General pfSense Questions
    28 Posts 5 Posters 2.1k Views 6 Watching
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • NogBadTheBadN Offline
      NogBadTheBad
      last edited by NogBadTheBad

      Might help if you mention what version of pfSense your running.

      https://nmap.org/nsedoc/

      Exploits CVE-2014-3704 also known as 'Drupageddon' in Drupal. Versions < 7.32 of Drupal core are known to be affected.

      Andy

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

      1 Reply Last reply Reply Quote 0
      • stephenw10S Offline
        stephenw10 Netgate Administrator
        last edited by

        Yeah I assumed that was the previous test which failed to run.

        What key length did you generate the new key at?

        Do you see that certs being used in a browser?

        Steve

        P 1 Reply Last reply Reply Quote 0
        • P Offline
          pooperman @stephenw10
          last edited by

          latest version of pfSense. Just set this up a week ago.

          new DH is 40xx bits

          1 Reply Last reply Reply Quote 0
          • 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

            1 Reply Last reply Reply Quote 1
            • 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

              1 Reply Last reply Reply Quote 1
              • 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

                    1 Reply Last reply Reply Quote 1
                    • 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

                        1 Reply Last reply Reply Quote 0
                        • 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

                          1 Reply Last reply Reply Quote 1
                          • 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/

                                      1 Reply Last reply Reply Quote 1
                                      • 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/

                                          1 Reply Last reply Reply Quote 0
                                          • 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

                                            1 Reply Last reply Reply Quote 0
                                            • First post
                                              Last post
                                            Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.