1 1 00:00:00,480 --> 00:00:02,810 Unneeded Services, in this lesson, 2 2 00:00:02,810 --> 00:00:04,520 we're going to discuss the best practices 3 3 00:00:04,520 --> 00:00:07,090 of disabling unneeded services and switch ports 4 4 00:00:07,090 --> 00:00:10,030 on our network devices, servers and workstations. 5 5 00:00:10,030 --> 00:00:13,290 So, let's first talk about unneeded services. 6 6 00:00:13,290 --> 00:00:15,710 Now, before we talk too much about unneeded services, 7 7 00:00:15,710 --> 00:00:18,380 it's important to define exactly what a service is 8 8 00:00:18,380 --> 00:00:19,830 in case you're not aware. 9 9 00:00:19,830 --> 00:00:21,830 Now, a service is a type of application 10 10 00:00:21,830 --> 00:00:22,930 that runs in the background 11 11 00:00:22,930 --> 00:00:24,520 of the operating system or device 12 12 00:00:24,520 --> 00:00:26,360 to perform a specific function. 13 13 00:00:26,360 --> 00:00:28,370 For example, on your Windows server, 14 14 00:00:28,370 --> 00:00:30,070 if you have a shared printer in your network, 15 15 00:00:30,070 --> 00:00:33,190 you might be running a Print Spooler, and this is a service. 16 16 00:00:33,190 --> 00:00:36,010 Or you might be running a DHCP server on your network. 17 17 00:00:36,010 --> 00:00:37,670 And this allows you to automatically configure 18 18 00:00:37,670 --> 00:00:39,640 IP addresses for all your clients. 19 19 00:00:39,640 --> 00:00:42,580 This DHCP server is a type of service. 20 20 00:00:42,580 --> 00:00:44,870 To ensure the highest levels of security for our network 21 21 00:00:44,870 --> 00:00:47,140 and reduce the attack surface of our devices, 22 22 00:00:47,140 --> 00:00:49,200 it's important that we disable any services 23 23 00:00:49,200 --> 00:00:51,480 that are not needed for business operations. 24 24 00:00:51,480 --> 00:00:54,100 For example, if I'm going to be using static IP addresses 25 25 00:00:54,100 --> 00:00:55,620 for all my network devices, 26 26 00:00:55,620 --> 00:00:57,810 I don't need to have a DHCP server. 27 27 00:00:57,810 --> 00:01:00,157 So, I can shut down the DHCP server 28 28 00:01:00,157 --> 00:01:03,780 and the associated services on the network for DHCP. 29 29 00:01:03,780 --> 00:01:05,460 You see, each service that we're running 30 30 00:01:05,460 --> 00:01:07,880 has to be installed on some kind of a device. 31 31 00:01:07,880 --> 00:01:10,830 Then that device is now using a valuable disc space, 32 32 00:01:10,830 --> 00:01:13,750 and more importantly, it's introducing additional code 33 33 00:01:13,750 --> 00:01:15,510 that could contain vulnerabilities. 34 34 00:01:15,510 --> 00:01:17,010 So to combat this, 35 35 00:01:17,010 --> 00:01:19,170 administrators attempt to practice a concept 36 36 00:01:19,170 --> 00:01:20,990 known as least functionality. 37 37 00:01:20,990 --> 00:01:22,840 Now least functionality is the process 38 38 00:01:22,840 --> 00:01:25,540 of configuring a device, a server or a workstation 39 39 00:01:25,540 --> 00:01:27,450 to only provide essential services 40 40 00:01:27,450 --> 00:01:29,490 that are required by the user. 41 41 00:01:29,490 --> 00:01:31,920 Now, to create an environment of least functionality, 42 42 00:01:31,920 --> 00:01:34,420 administrators should disable unneeded services, 43 43 00:01:34,420 --> 00:01:36,690 ports and protocols on the network. 44 44 00:01:36,690 --> 00:01:38,830 When dealing with hardening of your network devices, 45 45 00:01:38,830 --> 00:01:41,480 you may also want to disable infrequently used services 46 46 00:01:41,480 --> 00:01:44,070 that could be used by an attacker for malicious purposes. 47 47 00:01:44,070 --> 00:01:46,450 Things like a denial of service attack, for instance. 48 48 00:01:46,450 --> 00:01:49,320 For example, the Echo service runs on port seven, 49 49 00:01:49,320 --> 00:01:51,060 Discard runs on port nine. 50 50 00:01:51,060 --> 00:01:52,950 Daytime runs on port 13. 51 51 00:01:52,950 --> 00:01:55,150 And Chargen runs on port 19. 52 52 00:01:55,150 --> 00:01:58,450 These are all examples of some smaller TCP and UDP services 53 53 00:01:58,450 --> 00:02:00,860 that we hardly ever use in modern networks. 54 54 00:02:00,860 --> 00:02:02,270 But, if they're enabled, 55 55 00:02:02,270 --> 00:02:03,890 you want to make sure they're disabled 56 56 00:02:03,890 --> 00:02:05,690 to better harden your devices. 57 57 00:02:05,690 --> 00:02:08,110 Now, even if you are running a service on your network, 58 58 00:02:08,110 --> 00:02:10,680 you may not need to run it on every single device. 59 59 00:02:10,680 --> 00:02:13,390 So, you need to figure out which devices you need it on, 60 60 00:02:13,390 --> 00:02:15,620 and disable it on all the other devices, 61 61 00:02:15,620 --> 00:02:18,040 because otherwise, it's just additional vulnerabilities 62 62 00:02:18,040 --> 00:02:19,090 you're accepting. 63 63 00:02:19,090 --> 00:02:21,470 For example, if you're running your DHCP server 64 64 00:02:21,470 --> 00:02:23,050 on your windows domain controller, 65 65 00:02:23,050 --> 00:02:24,900 then you can disable the DHCP server 66 66 00:02:24,900 --> 00:02:27,030 that's built into one of your network devices. 67 67 00:02:27,030 --> 00:02:30,410 Or, if you're using DHCP, but you never plan to use BOOTP, 68 68 00:02:30,410 --> 00:02:32,750 which is an older dynamic configuration protocol, 69 69 00:02:32,750 --> 00:02:35,130 you can disable that on all of your network devices, 70 70 00:02:35,130 --> 00:02:37,110 so BOOTP is now disabled. 71 71 00:02:37,110 --> 00:02:37,980 The key here is that 72 72 00:02:37,980 --> 00:02:39,870 if you're not using a particular service, 73 73 00:02:39,870 --> 00:02:41,380 you need to disable it. 74 74 00:02:41,380 --> 00:02:43,970 So to help you disable those unneeded services, 75 75 00:02:43,970 --> 00:02:46,540 Cisco Network Devices provide the auto secure 76 76 00:02:46,540 --> 00:02:48,170 command line interface command 77 77 00:02:48,170 --> 00:02:50,430 that will disable any unnecessary services 78 78 00:02:50,430 --> 00:02:52,360 while enabling necessary security services 79 79 00:02:52,360 --> 00:02:54,040 on your network devices. 80 80 00:02:54,040 --> 00:02:56,070 Finally, let's talk about the switch ports 81 81 00:02:56,070 --> 00:02:57,940 on your network devices themselves. 82 82 00:02:57,940 --> 00:02:59,090 As a best practice, 83 83 00:02:59,090 --> 00:03:01,120 if nothing is connected to a given switch port 84 84 00:03:01,120 --> 00:03:04,480 on a switch or router, that interface should be disabled. 85 85 00:03:04,480 --> 00:03:06,720 To disable a switch port on a router or switch, 86 86 00:03:06,720 --> 00:03:08,120 you're going to go into the configuration 87 87 00:03:08,120 --> 00:03:09,230 command line interface 88 88 00:03:09,230 --> 00:03:11,400 and enter the interface you want to disable 89 89 00:03:11,400 --> 00:03:14,660 such as interface FastEthernet 0/1. 90 90 00:03:14,660 --> 00:03:17,390 Then you're going to enter the command shutdown. 91 91 00:03:17,390 --> 00:03:19,530 At this point, even if somebody plugs a cable 92 92 00:03:19,530 --> 00:03:22,570 into FastEthernet 0/1 on that switch port, 93 93 00:03:22,570 --> 00:03:23,950 it's not going to do anything 94 94 00:03:23,950 --> 00:03:25,880 because that port has been electronically 95 95 00:03:25,880 --> 00:03:27,520 shutdown and disabled. 96 96 00:03:27,520 --> 00:03:29,450 Now, let's pretend that that switch port 97 97 00:03:29,450 --> 00:03:31,930 that goes with FastEthernet 0/1 98 98 00:03:31,930 --> 00:03:33,270 is connected to the patch panel. 99 99 00:03:33,270 --> 00:03:35,480 And that patch panel is connected to a wall jack 100 100 00:03:35,480 --> 00:03:37,000 inside an empty office. 101 101 00:03:37,000 --> 00:03:38,830 Your company just hires a new employee, 102 102 00:03:38,830 --> 00:03:41,510 and now they're going to put that employee in that office. 103 103 00:03:41,510 --> 00:03:42,540 What are you going to do? 104 104 00:03:42,540 --> 00:03:44,750 Well, you need to re enable that wall jack. 105 105 00:03:44,750 --> 00:03:46,860 So you're going to log back into the switch. 106 106 00:03:46,860 --> 00:03:47,693 You're going to go into the 107 107 00:03:47,693 --> 00:03:49,150 configuration command line interface, 108 108 00:03:49,150 --> 00:03:52,580 and you're going to enter interface FastEthernet 0/1 109 109 00:03:52,580 --> 00:03:56,060 and then you're going to enter, no shutdown, that's it. 110 110 00:03:56,060 --> 00:03:58,160 The switch port will immediately turn itself back on 111 111 00:03:58,160 --> 00:04:00,440 and it's ready to send and receive traffic again. 112 112 00:04:00,440 --> 00:04:02,530 So it really doesn't take a lot of effort to turn off 113 113 00:04:02,530 --> 00:04:04,140 or turn on when they switch ports. 114 114 00:04:04,140 --> 00:04:06,540 That's why it's a best practice to always disable them 115 115 00:04:06,540 --> 00:04:07,970 when they're not in use. 116 116 00:04:07,970 --> 00:04:09,830 Now, each network device manufacturer 117 117 00:04:09,830 --> 00:04:11,450 is going to use their own commands. 118 118 00:04:11,450 --> 00:04:13,970 The one I just covered were for Cisco devices, 119 119 00:04:13,970 --> 00:04:15,280 because they're most commonly used 120 120 00:04:15,280 --> 00:04:16,900 in large business networks. 121 121 00:04:16,900 --> 00:04:19,210 If you're going to be using a different brand or manufacturer, 122 122 00:04:19,210 --> 00:04:21,100 simply check your manual or Google, 123 123 00:04:21,100 --> 00:04:24,290 how to shut down and enable switch ports on those devices. 124 124 00:04:24,290 --> 00:04:26,010 After all, even if there's no cables 125 125 00:04:26,010 --> 00:04:27,320 connected to a switch port, 126 126 00:04:27,320 --> 00:04:30,490 an open switch port is going to represent a vulnerability. 127 127 00:04:30,490 --> 00:04:31,630 Think about it this way. 128 128 00:04:31,630 --> 00:04:32,870 What would happen if an attacker 129 129 00:04:32,870 --> 00:04:34,520 made their way past your security 130 130 00:04:34,520 --> 00:04:36,440 and were able to get to where the switch is. 131 131 00:04:36,440 --> 00:04:37,710 They could just plug into it 132 132 00:04:37,710 --> 00:04:39,530 and immediately have access to the network. 133 133 00:04:39,530 --> 00:04:40,930 That would be a really bad thing 134 134 00:04:40,930 --> 00:04:43,430 because all the switch ports are enabled by default. 135 135 00:04:43,430 --> 00:04:44,980 So we want to make sure we disable 136 136 00:04:44,980 --> 00:04:46,500 any of them that we're not using. 137 137 00:04:46,500 --> 00:04:48,750 Remember just like an unneeded service, 138 138 00:04:48,750 --> 00:04:50,290 if there's an unneeded switch port, 139 139 00:04:50,290 --> 00:04:51,530 you should always disable it 140 140 00:04:51,530 --> 00:04:52,850 to reduce your attack surface 141 141 00:04:52,850 --> 00:04:55,000 and increase the security of your networks.