1 1 00:00:00,270 --> 00:00:02,610 Jump box, in the last lesson, 2 2 00:00:02,610 --> 00:00:04,320 I introduced the concepts of zones 3 3 00:00:04,320 --> 00:00:06,270 and I started talking about screened subnets. 4 4 00:00:06,270 --> 00:00:08,670 In this lesson, I want to dig a little bit further into that 5 5 00:00:08,670 --> 00:00:10,650 and then talk about how we can manage them. 6 6 00:00:10,650 --> 00:00:12,210 So the first thing I had mentioned was 7 7 00:00:12,210 --> 00:00:14,370 if you have an internet facing host. 8 8 00:00:14,370 --> 00:00:16,260 Now I didn't really go into what that was, so let me take 9 9 00:00:16,260 --> 00:00:18,660 a step here and go ahead and define it for you. 10 10 00:00:18,660 --> 00:00:20,430 When I'm talking about something that's internet facing 11 11 00:00:20,430 --> 00:00:21,690 like an internet facing host 12 12 00:00:21,690 --> 00:00:24,300 or an internet facing server I'm talking about a host 13 13 00:00:24,300 --> 00:00:26,280 or server that accepts inbound connections 14 14 00:00:26,280 --> 00:00:27,360 from the internet. 15 15 00:00:27,360 --> 00:00:29,550 So if I have a web server in my screened subnet 16 16 00:00:29,550 --> 00:00:31,680 that is an internet facing host. 17 17 00:00:31,680 --> 00:00:33,480 So you can see here again if I bring up my diagram, 18 18 00:00:33,480 --> 00:00:35,400 I have my inside zone, my screened subnet 19 19 00:00:35,400 --> 00:00:36,780 and my outside zone. 20 20 00:00:36,780 --> 00:00:40,020 In that screened subnet, I have two internet facing hosts. 21 21 00:00:40,020 --> 00:00:42,570 I have an email server and a web server. 22 22 00:00:42,570 --> 00:00:44,340 Now, only the email and web servers that are 23 23 00:00:44,340 --> 00:00:46,620 in the screened subnet are going to be able to get traffic 24 24 00:00:46,620 --> 00:00:50,130 from the outside even though they haven't requested it. 25 25 00:00:50,130 --> 00:00:52,350 So if you want to connect to my web server 26 26 00:00:52,350 --> 00:00:54,210 you're going to go to diontraining.com 27 27 00:00:54,210 --> 00:00:56,100 and it's going to go through my screened subnet 28 28 00:00:56,100 --> 00:00:59,070 into my web server and then give you back your response. 29 29 00:00:59,070 --> 00:01:01,350 Now, if you wanted to get to PC two or PC three 30 30 00:01:01,350 --> 00:01:03,540 in my inside network you couldn't do that 31 31 00:01:03,540 --> 00:01:04,830 because the firewall would block you. 32 32 00:01:04,830 --> 00:01:06,810 Those are not internet facing. 33 33 00:01:06,810 --> 00:01:08,370 They have access to the internet 34 34 00:01:08,370 --> 00:01:09,840 but they're not facing the internet 35 35 00:01:09,840 --> 00:01:12,390 meaning they are not open and waiting for a connection. 36 36 00:01:12,390 --> 00:01:13,560 That's the difference when you're dealing 37 37 00:01:13,560 --> 00:01:15,150 with internet facing hosts. 38 38 00:01:15,150 --> 00:01:16,800 Now, anytime you have internet facing hosts 39 39 00:01:16,800 --> 00:01:18,660 you want to place them into someplace secure 40 40 00:01:18,660 --> 00:01:20,100 like your screened subnet. 41 41 00:01:20,100 --> 00:01:22,320 Now your screened subnet is actually a segment 42 42 00:01:22,320 --> 00:01:25,230 that is isolated from the rest of the private network by one 43 43 00:01:25,230 --> 00:01:27,750 or more firewalls, and it's set up to accept connections 44 44 00:01:27,750 --> 00:01:30,180 from the internet over designated ports. 45 45 00:01:30,180 --> 00:01:31,680 Now, the reason we do this is we want to 46 46 00:01:31,680 --> 00:01:33,570 keep all those forward facing servers 47 47 00:01:33,570 --> 00:01:35,250 out of our internal network. 48 48 00:01:35,250 --> 00:01:36,083 We don't want people 49 49 00:01:36,083 --> 00:01:37,620 from the internet touching our internal network. 50 50 00:01:37,620 --> 00:01:39,540 We only want them in our screened subnet. 51 51 00:01:39,540 --> 00:01:41,880 This place that is kind of this semi-trusted zone. 52 52 00:01:41,880 --> 00:01:44,280 And we know that anything that's behind the screened subnet, 53 53 00:01:44,280 --> 00:01:45,840 such as my inside zone, 54 54 00:01:45,840 --> 00:01:48,030 is actually invisible to the outside network. 55 55 00:01:48,030 --> 00:01:50,850 So if you start scanning my network from the outside 56 56 00:01:50,850 --> 00:01:52,860 you're not going to see all those PCs inside 57 57 00:01:52,860 --> 00:01:53,970 of the inside zone. 58 58 00:01:53,970 --> 00:01:55,950 Instead, you're only going to see the web server 59 59 00:01:55,950 --> 00:01:57,000 and the email server 60 60 00:01:57,000 --> 00:02:00,000 'cause those are forward facing and they're internet facing. 61 61 00:02:00,000 --> 00:02:01,650 Now the next thing we need to talk about in terms 62 62 00:02:01,650 --> 00:02:03,060 of the screened subnet is what kind 63 63 00:02:03,060 --> 00:02:05,220 of stuff should you put in the screened subnet? 64 64 00:02:05,220 --> 00:02:06,810 You could see here that I have my email 65 65 00:02:06,810 --> 00:02:08,580 and my web server and the screened subnet. 66 66 00:02:08,580 --> 00:02:10,470 Any other kind of communication servers, 67 67 00:02:10,470 --> 00:02:13,110 proxy servers or remote access servers should also be 68 68 00:02:13,110 --> 00:02:14,250 in the screened subnet. 69 69 00:02:14,250 --> 00:02:16,170 Anything that somebody from the internet needs access 70 70 00:02:16,170 --> 00:02:18,480 to should be placed in your screened subnet. 71 71 00:02:18,480 --> 00:02:20,580 This is essentially anything that provides public services 72 72 00:02:20,580 --> 00:02:22,770 or even extranet capabilities. 73 73 00:02:22,770 --> 00:02:24,960 Any of your hosts that are in the screened subnet 74 74 00:02:24,960 --> 00:02:27,780 we don't fully trust those even though there're our devices. 75 75 00:02:27,780 --> 00:02:30,450 So we want to make sure that we harden them as best as we can. 76 76 00:02:30,450 --> 00:02:31,920 And we have to remember that those devices 77 77 00:02:31,920 --> 00:02:34,020 because they're forward facing, they could be touched 78 78 00:02:34,020 --> 00:02:36,630 by an attacker, they could be compromised by an attacker. 79 79 00:02:36,630 --> 00:02:38,160 So that's why they're not fully trusted 80 80 00:02:38,160 --> 00:02:39,420 to our internal network 81 81 00:02:39,420 --> 00:02:42,000 and that's why we actually have it go through the firewall. 82 82 00:02:42,000 --> 00:02:43,770 Anything that's going from the screened subnet 83 83 00:02:43,770 --> 00:02:45,750 to the inside and from the inside back 84 84 00:02:45,750 --> 00:02:46,800 to the screened subnet. 85 85 00:02:46,800 --> 00:02:49,440 That's another good place to put intrusion detection systems 86 86 00:02:49,440 --> 00:02:51,840 to make sure that you're catching anything that may be going 87 87 00:02:51,840 --> 00:02:54,120 from your screened subnet, because a common technique 88 88 00:02:54,120 --> 00:02:55,770 for an attacker is to compromise something 89 89 00:02:55,770 --> 00:02:56,760 in the screened subnet 90 90 00:02:56,760 --> 00:02:59,160 and use that to pivot into your network. 91 91 00:02:59,160 --> 00:03:01,200 So you want to protect yourself against that. 92 92 00:03:01,200 --> 00:03:03,570 Now, any kind of host you put in the screened subnet 93 93 00:03:03,570 --> 00:03:06,330 should really be what we consider a Bastion host. 94 94 00:03:06,330 --> 00:03:08,070 This is a host or server that we put 95 95 00:03:08,070 --> 00:03:10,410 into the screened subnet, which is not configured 96 96 00:03:10,410 --> 00:03:13,260 with any services that run on the local network. 97 97 00:03:13,260 --> 00:03:14,430 So I don't want to run something 98 98 00:03:14,430 --> 00:03:16,920 like active directory inside the screened subnet, 99 99 00:03:16,920 --> 00:03:19,050 that that's an internal network service. 100 100 00:03:19,050 --> 00:03:21,120 Instead, I only want to run things that should be 101 101 00:03:21,120 --> 00:03:21,953 in the internet. 102 102 00:03:21,953 --> 00:03:24,120 Things like email, things like web, 103 103 00:03:24,120 --> 00:03:26,910 things like remote access, those things can be hardened 104 104 00:03:26,910 --> 00:03:28,830 and put into the screened subnet because we know 105 105 00:03:28,830 --> 00:03:31,110 that they're going to be more vulnerable to attack. 106 106 00:03:31,110 --> 00:03:32,850 Now when we want to configure our devices 107 107 00:03:32,850 --> 00:03:35,130 inside the screened subnet, what you going to do? 108 108 00:03:35,130 --> 00:03:37,920 Well, we're going to use something known as a jump box. 109 109 00:03:37,920 --> 00:03:40,890 Now a jump box is a hardened server that provides access 110 110 00:03:40,890 --> 00:03:42,900 to other hosts within the screened subnet. 111 111 00:03:42,900 --> 00:03:44,940 So essentially we have this one server 112 112 00:03:44,940 --> 00:03:47,340 and it is what can talk to the screened subnet 113 113 00:03:47,340 --> 00:03:49,950 and we configure all the access control to make sure 114 114 00:03:49,950 --> 00:03:51,720 that only the jump box can communicate 115 115 00:03:51,720 --> 00:03:53,970 from the internal network to the screened subnet. 116 116 00:03:53,970 --> 00:03:55,020 Now because of that 117 117 00:03:55,020 --> 00:03:57,090 that jump box has to be heavily hardened. 118 118 00:03:57,090 --> 00:03:58,530 It needs to be protected. 119 119 00:03:58,530 --> 00:04:00,690 And what ends up happening is the administrator will connect 120 120 00:04:00,690 --> 00:04:02,970 to the jump box and then the jump box will connect 121 121 00:04:02,970 --> 00:04:04,263 to the host and the screened subnet. 122 122 00:04:04,263 --> 00:04:05,490 Then I call it a jump box 123 123 00:04:05,490 --> 00:04:07,320 'cause we're almost pivoting off of it. 124 124 00:04:07,320 --> 00:04:09,000 We're going to connect from me to the jump box 125 125 00:04:09,000 --> 00:04:11,250 and the jump box to the server I want to configure 126 126 00:04:11,250 --> 00:04:13,140 and that's how we call it a jump box. 127 127 00:04:13,140 --> 00:04:15,180 Now, this jump box can be a physical PC 128 128 00:04:15,180 --> 00:04:16,590 or it can be a virtual machine. 129 129 00:04:16,590 --> 00:04:17,850 Either one is fine. 130 130 00:04:17,850 --> 00:04:20,370 A lot of people use virtual machines as a jump box 131 131 00:04:20,370 --> 00:04:23,160 because you can have it hardened and secured. 132 132 00:04:23,160 --> 00:04:25,560 You can use it for the time you need and then destroy it 133 133 00:04:25,560 --> 00:04:27,450 and rebuild a new one because it's very quick 134 134 00:04:27,450 --> 00:04:29,580 to rebuild an image from a virtual machine 135 135 00:04:29,580 --> 00:04:31,590 if you already have a known good image. 136 136 00:04:31,590 --> 00:04:33,630 And so a lot of people will do it that way. 137 137 00:04:33,630 --> 00:04:35,760 Now, the jump box and the management workstation 138 138 00:04:35,760 --> 00:04:37,680 that you're using to connect to that jump box 139 139 00:04:37,680 --> 00:04:40,320 should have only the minimum required software to 140 140 00:04:40,320 --> 00:04:43,110 perform their job and they should be well hardened. 141 141 00:04:43,110 --> 00:04:45,870 Again, this is the one box that has the permissions 142 142 00:04:45,870 --> 00:04:46,920 to go through the firewall 143 143 00:04:46,920 --> 00:04:49,770 and touch the screened subnet from your internal network. 144 144 00:04:49,770 --> 00:04:52,650 So you want to make sure it is well protected. 145 145 00:04:52,650 --> 00:04:54,570 This is why you want to make sure that management workstation 146 146 00:04:54,570 --> 00:04:56,580 and the jump box are fully hardened 147 147 00:04:56,580 --> 00:04:58,560 and they have the least amount of software on 148 148 00:04:58,560 --> 00:05:01,510 them to make sure they're fully hardened and fully secured.