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    Verifying SSL site certificate verification

    Scheduled Pinned Locked Moved General pfSense Questions
    21 Posts 7 Posters 3.5k Views
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    • J Offline
      Jdwind
      last edited by

      But SSL MITM is more security (in my opinion, if I'm not wrong?), how to otherwise filtering https sites with proxy?

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      • DerelictD Offline
        Derelict LAYER 8 Netgate
        last edited by

        Well, then you have a choice to make.

        Look at https peek/splice

        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 Online
          johnpoz LAYER 8 Global Moderator
          last edited by

          More security for who exactly? You can filter users from going to sites you don't want them to go to without having to do a MITM on the ssl.  If your doing a MITM the user would not be able to see the end cert, only the cert you present them.

          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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          • J Offline
            Jdwind
            last edited by

            Thank you very much for a explnation, but can you tell me how can I filter sites with SSL and the same time have anti-virus protection enabled for them?

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            • johnpozJ Online
              johnpoz LAYER 8 Global Moderator
              last edited by

              You would not be able to scan for antivirus inside a ssl tunnel.  The client would do this on their end..  You wouldn't do this on the firewall.

              But you can filter what sites they go to without having to do a mitm on the ssl.. Doing mitm opens up a whole can of worms.. You would then be able to sniff users passwords to like their banks, and such.  View medical info they might be looking at.

              SSL is suppose to provide end to end security.. From the end user to the site they are going to.. When you break that trust by doing a mitm you can open up a whole freaking can of issues that are best left alone..

              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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              • J Offline
                Jdwind
                last edited by

                So, if you can (please), tell me, what should I do to do? Use transparent squid proxy without MITM? And how to manage ssl sites (i.e. how to block youtube, facebook etc. for some users in my network)?
                Best regards and thank you very much.

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                • DerelictD Offline
                  Derelict LAYER 8 Netgate
                  last edited by

                  peek/splice, not MITM.

                  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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                  • J Offline
                    Jdwind
                    last edited by

                    Then what should I to do? Disable MITM, enable transparent proxy in squid? I found only in Squid (in SSL Man In the Middle Filtering section) that information: Please see SslBump Peek and Splice wiki documentation for additional details - but there http://wiki.squid-cache.org/Features/SslPeekAndSplice is not information how use it with Pfsense. Can you tell me some more about how do that, please?

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                    • C Offline
                      Chrismallia
                      last edited by

                      Here is mine

                      sp.PNG
                      sp.PNG_thumb

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                      • D Offline
                        doktornotor Banned
                        last edited by

                        @Jdwind:

                        But SSL MITM is more security

                        https://www.us-cert.gov/ncas/alerts/TA17-075A

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                        • J Offline
                          Jdwind
                          last edited by

                          Thank you, doktornotor. I have installed end-point antyvirus on every host too. In my network I must have any security solution (like IPS/IDS - I use Snort package), that why I used MITM and SSL filtering. Chrismallia show his configuration, but if I am not wrong he has MITM and SSL filtering too. Only different is with SSL/MITM mode - I have default, he Splice All. That's all?

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                          • C Offline
                            Chrismallia
                            last edited by

                            with splice all you do not need to install certs on devices, it is mostly good for only filtering  no AV, so it does not break the  ssl connection  or inspect content, it uses the SNI, anyone correct me if I am mistaken in any way

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                            • D Offline
                              doktornotor Banned
                              last edited by

                              @Jdwind:

                              Thank you, doktornotor. I have installed end-point antyvirus on every host too.

                              Oh noes. That was NOT the point. The point was that MITM is evil.

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                              • J Offline
                                Jdwind
                                last edited by

                                I tried this settings (from Chrismallia) on virtual network, Pfsense and two hosts and  what can I say… it works. Antivirus dont works with SSL, but I have it installed on every host. Thank you all for help and explanation very, very much. But one thing more that I can't understand (after Doktornotor post) - it is still MITM enabled - does it matter?
                                Best regards

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                                • johnpozJ Online
                                  johnpoz LAYER 8 Global Moderator
                                  last edited by

                                  no with splice your not your doing a peek and then splicing it back.. The client is getting the actual cert from the server.. Your just peaking inside to see where they are going, etc.  And if it should be filtered.

                                  "splice: Become a TCP tunnel without decoding the connection. The client and the server exchange data as if there is no proxy in between."

                                  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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                                  • J Offline
                                    Jdwind
                                    last edited by

                                    Thank you very much again, so now I have everything ok. With Squidguard ssl filtering just works.

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                                    • H Offline
                                      Harvy66
                                      last edited by

                                      There are many attack vectors to infect machines when MITM is used. SSL provides two things, privacy and security. The security is provided by the signing. When you MITM, you break the signing, which means you break the security.

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                                      • K Offline
                                        kpa
                                        last edited by

                                        With MITM you're breaking the chain of trust normally provided the trusted third party signatures found on the certificates. Your users will no longer be able to verify that they are connecting to the real deal when they connect to a HTTPS site, instead they can at maximum be sure only that they are connecting to your MITM proxy.

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                                        • J Offline
                                          Jdwind
                                          last edited by

                                          It is too much  for my mind… Yes, now I know you are both right. But now, when I'm using peek and splice all mode with MITM and I can see every certificate verificated by.. i.e. Verisign, Symante, Oracle.. now my network settings are right - am I right or am I wrong?
                                          EDIT:
                                          I found that thread https://forum.pfsense.org/index.php?topic=123461.0, there is more explanation about my doubts. Thank you once more.

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