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    DDoS attacks OpenVPN on Pfsense

    Scheduled Pinned Locked Moved Firewalling
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    • N
      netblues
      last edited by

      Are you using a static tls key?
      Quoting from pfsense configuration screen

      A TLS key enhances security of an OpenVPN connection by requiring both parties >to have a common key before a peer can perform a TLS handshake. This layer of HMAC authentication allows control channel packets without the proper key to be dropped, protecting the peers from attack or unauthorized connections.The TLS Key does not have any effect on tunnel data.

      Puts much less strain on the box and you don't have to administer ip's anymore
      Just an idea.

      DerelictD 1 Reply Last reply Reply Quote 0
      • KOMK
        KOM
        last edited by

        I don't understand. I've been running OpenVPN for years now, and I've never had any ghost connections tying everything up. I'm being scanned and probed just as much as everyone else. Nothing ever connects to it except for valid users. Does this happen to anyone else? In all my years here, I've never heard of a similar complaint. Is this actually a real problem?

        L GertjanG 2 Replies Last reply Reply Quote 0
        • johnpozJ
          johnpoz LAYER 8 Global Moderator
          last edited by

          I have never see bogus hits on openvpn tie up a connection no..

          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 2.7.2, 24.11

          1 Reply Last reply Reply Quote 0
          • L
            leungda @KOM
            last edited by

            @kom

            I can say you are lucky

            1 Reply Last reply Reply Quote 0
            • DerelictD
              Derelict LAYER 8 Netgate @netblues
              last edited by

              @netblues said in DDoS attacks OpenVPN on Pfsense:

              Are you using a static tls key?

              Are you using a static TLS key? How is your server configured?

              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
              • GertjanG
                Gertjan @KOM
                last edited by

                @kom said in DDoS attacks OpenVPN on Pfsense:

                Does this happen to anyone else?

                #Metoo.
                Having a static IPv4 your years now, but never saw something like that.
                TLS Keys : of course, I use these.

                No "help me" PM's please. Use the forum, the community will thank you.
                Edit : and where are the logs ??

                1 Reply Last reply Reply Quote 0
                • L
                  leungda
                  last edited by leungda

                  two different sites got attacked. They are different client and network. They got attacked with the same IP address.

                  How can i extract OpenVPN log from pfsense

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

                    @leungda

                    Whats the IP address, it's not comming from shodan or shadowserver is it ?

                    I get these almost every day poking my IPsec VPN, create a blacklist in snort if it is.

                    shadowserver:-
                    
                    216.218.206.0/24
                    
                    shodan:-
                    
                    198.20.69.72/29		# census1.shodan.io
                    198.20.69.96/29		# census2.shodan.io
                    198.20.70.112/29	# census3.shodan.io
                    198.20.99.128/29	# census4.shodan.io
                    93.120.27.62		# census5.shodan.io
                    66.240.236.119		# census6.shodan.io
                    71.6.135.131		# census7.shodan.io
                    66.240.192.138		# census8.shodan.io
                    71.6.167.142		# census9.shodan.io
                    82.221.105.6		# census10.shodan.io
                    82.221.105.7		# census11.shodan.io
                    71.6.165.200		# census12.shodan.io
                    188.138.9.50		# atlantic.census.shodan.io
                    85.25.103.50		# pacific.census.shodan.io
                    85.25.43.94			# rim.census.shodan.io
                    71.6.146.185		# pirate.census.shodan.io
                    71.6.146.186		# inspire.census.shodan.io
                    71.6.158.166		# ninja.census.shodan.io
                    198.20.87.96/29		# border.census.shodan.io
                    66.240.219.146		# burger.census.shodan.io
                    209.126.110.38		# atlantic.dns.shodan.io
                    104.236.198.48		# blog.shodan.io
                    104.131.0.69		# hello.data.shodan.io
                    162.159.244.38		# www.shodan.io
                    159.203.176.62		# ny.private.shodan.io
                    188.138.1.119		# atlantic249.serverprofi24.com
                    80.82.77.33		# sky.census.shodan.io
                    80.82.77.139		# dojo.census.shodan.io
                    71.6.146.130		# ubtuntu16146130.aspadmin.com
                    66.240.205.34		# shodan.io
                    216.117.2.180		# malware-hunter.census.shodan.io
                    93.174.95.106		# battery.census.shodan.io
                    89.248.172.16		# house.census.shodan.io
                    185.163.109.66		# goldfish.census.shodan.io
                    93.174.95.106		# battery.census.shodan.io
                    89.248.167.131		# mason.census.shodan.io
                    94.102.49.190		# flower.census.shodan.io
                    94.102.49.193		# cloud.census.shodan.io
                    185.181.102.18		# turtle.census.shodan.io
                    

                    Andy

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

                    1 Reply Last reply Reply Quote 0
                    • L
                      leungda
                      last edited by

                      Could you tell me how to create a blacklist in snort?

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

                        Create the blacklist file:-

                        0_1536609734495_Untitled.jpeg

                        Apply it to the interface:-

                        0_1536609743860_Untitled 2.jpeg

                        You then should see (spp_reputation) packets blacklisted in the blocked list:-

                        0_1536609872518_Untitled 3.jpeg

                        Andy

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

                        1 Reply Last reply Reply Quote 0
                        • L
                          leungda
                          last edited by

                          Love it. Thanks for your help

                          1 Reply Last reply Reply Quote 0
                          • KOMK
                            KOM
                            last edited by

                            @netblues said in DDoS attacks OpenVPN on Pfsense:

                            Are you using a static tls key?

                            You have been asked this twice now. It's hard to help you when you don't answer questions.

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

                              You have ZERO need of snort to stop traffic from hitting your wan IP on your openvpn port - ZERO!!!

                              Im with kom - you going to answer the simple TLS key question??

                              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 2.7.2, 24.11

                              1 Reply Last reply Reply Quote 0
                              • L
                                leungda
                                last edited by leungda

                                I checked. I didn't use TLS key on OpenVPN setting. Might be you can help me to set this up for extra layer.

                                My OpenVPN set up look like this

                                SSL/TLS + user auth -> DUO -> AD for people to sign in. I am not using local database for user auth

                                Do you sugguest any online guide that I can read of TLS?

                                1 Reply Last reply Reply Quote 0
                                • KOMK
                                  KOM
                                  last edited by

                                  I think you just have to check the Use a TLS key box and then generate new user config that has the TLS key embedded in the .ovpn file, for instance.

                                  1 Reply Last reply Reply Quote 0
                                  • N
                                    netblues
                                    last edited by

                                    The guide on openvpn hardening has lots of info
                                    https://community.openvpn.net/openvpn/wiki/Hardening
                                    tls key is described in section Use of --tls-auth
                                    As for pfsense, its rather straight forward to implement what it suggests.
                                    It also means that you need to send the tls.key to all your clients somehow.
                                    Now if you are running clients by the thousands, this is definitely an issue on its own.
                                    Imagine this as an initial passphrase. If the client connecting knows it, thserver will deal with him further, spending computing resources to do all the needed security handshakes
                                    Obviously it won;t help if you are experiencing a network level attack, ie ping flood saturating your line.

                                    1 Reply Last reply Reply Quote 0
                                    • L
                                      leungda
                                      last edited by leungda

                                      I got the TLS in place at one site. I will keep my eyes on it for the next few days. Also, set up a blocklist on Snort is also a good idea.

                                      This guide is quite useful too. Thanks
                                      https://community.openvpn.net/openvpn/wiki/Hardening

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