1 1 00:00:00,270 --> 00:00:02,340 Hardening and patching. 2 2 00:00:02,340 --> 00:00:05,220 In this lesson, we're going to talk about two key terms 3 3 00:00:05,220 --> 00:00:06,840 and I know I've used these words before, 4 4 00:00:06,840 --> 00:00:08,490 but we've never really defined them. 5 5 00:00:08,490 --> 00:00:10,800 These are hardening and patching. 6 6 00:00:10,800 --> 00:00:12,720 Now, when I talk about system hardening, 7 7 00:00:12,720 --> 00:00:15,570 this is the process by which a host or other device 8 8 00:00:15,570 --> 00:00:16,860 is made more secure 9 9 00:00:16,860 --> 00:00:20,220 through the reduction of a device's attack surface area. 10 10 00:00:20,220 --> 00:00:21,330 Now, what does that mean 11 11 00:00:21,330 --> 00:00:23,430 when I talk about an attack surface area? 12 12 00:00:23,430 --> 00:00:25,380 Well, when I talk about an attack surface, 13 13 00:00:25,380 --> 00:00:27,750 I'm talking about the services and the interfaces 14 14 00:00:27,750 --> 00:00:29,100 that allow a user or program 15 15 00:00:29,100 --> 00:00:31,440 to communicate with a target system. 16 16 00:00:31,440 --> 00:00:34,290 This allows all of these different services that are there 17 17 00:00:34,290 --> 00:00:36,990 to be vulnerable for somebody to attack them, right? 18 18 00:00:36,990 --> 00:00:38,150 And that's the idea of system hardening, 19 19 00:00:38,150 --> 00:00:40,980 is I want to close down as many of those as I don't need 20 20 00:00:40,980 --> 00:00:42,930 because that will end up hardening my system 21 21 00:00:42,930 --> 00:00:45,270 and reducing that attack surface. 22 22 00:00:45,270 --> 00:00:47,340 Now, any service or interface that is enabled 23 23 00:00:47,340 --> 00:00:50,220 through the default installation and left unconfigured 24 24 00:00:50,220 --> 00:00:52,290 should be considered a vulnerability. 25 25 00:00:52,290 --> 00:00:54,480 And so, you should scan that, you should identify it 26 26 00:00:54,480 --> 00:00:56,700 and then mitigate or remediate that 27 27 00:00:56,700 --> 00:00:57,900 based on what you need to do 28 28 00:00:57,900 --> 00:01:00,000 as part of your system hardening. 29 29 00:01:00,000 --> 00:01:02,190 Now, when we start talking about system hardening, 30 30 00:01:02,190 --> 00:01:05,640 I have this wonderful system hardening security checklist. 31 31 00:01:05,640 --> 00:01:08,010 These are 10 major areas that you need to check 32 32 00:01:08,010 --> 00:01:10,020 when you're trying to harden a given system. 33 33 00:01:10,020 --> 00:01:12,690 First, you need to remove or disable devices 34 34 00:01:12,690 --> 00:01:14,640 that are not needed or used. 35 35 00:01:14,640 --> 00:01:17,010 For example, are you using wifi? 36 36 00:01:17,010 --> 00:01:20,250 If not, disable it and take out the wifi card. 37 37 00:01:20,250 --> 00:01:22,530 Are you using a CD-ROM or a floppy drive? 38 38 00:01:22,530 --> 00:01:24,510 If not, take those things out. 39 39 00:01:24,510 --> 00:01:27,210 Anything you don't need, you should remove or disable 40 40 00:01:27,210 --> 00:01:28,590 because anything you don't need 41 41 00:01:28,590 --> 00:01:30,180 is another thing that's open 42 42 00:01:30,180 --> 00:01:31,590 and could be used by an attacker 43 43 00:01:31,590 --> 00:01:33,990 and that makes it part of our larger attack surface. 44 44 00:01:33,990 --> 00:01:36,300 So by removing it, we are going to harden our system 45 45 00:01:36,300 --> 00:01:38,250 and reduce the attack surface. 46 46 00:01:38,250 --> 00:01:40,830 The second thing is we want to install operating system, 47 47 00:01:40,830 --> 00:01:44,250 application firmware and driver patches regularly. 48 48 00:01:44,250 --> 00:01:46,470 If Microsoft knows there's a vulnerability in Windows 49 49 00:01:46,470 --> 00:01:48,570 and they put out a patch on Patch Tuesday, 50 50 00:01:48,570 --> 00:01:50,070 you should be downloading that patch, 51 51 00:01:50,070 --> 00:01:50,970 testing that patch 52 52 00:01:50,970 --> 00:01:53,520 and then deploying that patch across your network 53 53 00:01:53,520 --> 00:01:56,310 because you want to make sure you are patched regularly 54 54 00:01:56,310 --> 00:01:59,040 and up to date with the latest security precautions. 55 55 00:01:59,040 --> 00:02:01,200 Because if somebody has a patch out there, 56 56 00:02:01,200 --> 00:02:03,210 bad guys will usually reverse engineer that patch 57 57 00:02:03,210 --> 00:02:04,410 and create an exploit. 58 58 00:02:04,410 --> 00:02:06,540 So you need to make sure that you are patched 59 59 00:02:06,540 --> 00:02:07,650 to prevent those exploits 60 60 00:02:07,650 --> 00:02:09,720 from being effective against your systems. 61 61 00:02:09,720 --> 00:02:11,280 The third thing I want you to think about 62 62 00:02:11,280 --> 00:02:14,400 is uninstalling all unnecessary network protocols. 63 63 00:02:14,400 --> 00:02:17,400 Now what I mean here is not necessarily your wifi, 64 64 00:02:17,400 --> 00:02:19,410 but instead all of those network protocols 65 65 00:02:19,410 --> 00:02:21,180 that might be used on your system. 66 66 00:02:21,180 --> 00:02:22,380 Are you running a web server? 67 67 00:02:22,380 --> 00:02:24,330 If you're not, close port 80. 68 68 00:02:24,330 --> 00:02:25,470 Are you running a mail server? 69 69 00:02:25,470 --> 00:02:27,630 If not, close port 25. 70 70 00:02:27,630 --> 00:02:28,980 Are you running an SSH server? 71 71 00:02:28,980 --> 00:02:31,140 If not, close port 22. 72 72 00:02:31,140 --> 00:02:32,490 As a standard workstation, 73 73 00:02:32,490 --> 00:02:34,620 you really should have no ports that are open 74 74 00:02:34,620 --> 00:02:35,580 unless you have something open 75 75 00:02:35,580 --> 00:02:38,160 for something like a host-based intrusion detection system 76 76 00:02:38,160 --> 00:02:40,770 to be able to receive reports and send reports back. 77 77 00:02:40,770 --> 00:02:41,910 Other than that, everything should be 78 78 00:02:41,910 --> 00:02:43,980 pretty much locked down on a system. 79 79 00:02:43,980 --> 00:02:46,080 On a server, you should only have the ports open 80 80 00:02:46,080 --> 00:02:47,460 for the services you need. 81 81 00:02:47,460 --> 00:02:48,690 So if you're running a file server 82 82 00:02:48,690 --> 00:02:50,760 or a web server or an email server, 83 83 00:02:50,760 --> 00:02:51,900 those ports should be open, 84 84 00:02:51,900 --> 00:02:53,970 but everything else should be closed. 85 85 00:02:53,970 --> 00:02:55,200 The fourth thing we want to look at 86 86 00:02:55,200 --> 00:02:58,230 is uninstalling or disabling all unnecessary services 87 87 00:02:58,230 --> 00:02:59,880 and shared folders. 88 88 00:02:59,880 --> 00:03:01,830 Anytime you have something that is open 89 89 00:03:01,830 --> 00:03:03,390 or shared or a service, 90 90 00:03:03,390 --> 00:03:05,160 that is, again, something that is increasing 91 91 00:03:05,160 --> 00:03:06,330 your attack surface. 92 92 00:03:06,330 --> 00:03:08,700 So again, you're seeing the common theme here. 93 93 00:03:08,700 --> 00:03:09,870 Anything you're not using, 94 94 00:03:09,870 --> 00:03:12,060 go ahead and uninstall it or disable it. 95 95 00:03:12,060 --> 00:03:13,170 I prefer to uninstall it 96 96 00:03:13,170 --> 00:03:14,940 because that way nobody else can enable it, 97 97 00:03:14,940 --> 00:03:16,350 but if you can't uninstall it, 98 98 00:03:16,350 --> 00:03:18,300 then you should at least disable it. 99 99 00:03:18,300 --> 00:03:21,000 Fifth, you need to enforce access control lists 100 100 00:03:21,000 --> 00:03:22,620 on all system resources. 101 101 00:03:22,620 --> 00:03:24,660 This means if you have local system files 102 102 00:03:24,660 --> 00:03:27,420 or folders or shared files in folders or printers, 103 103 00:03:27,420 --> 00:03:29,160 all of those things have to be controlled 104 104 00:03:29,160 --> 00:03:31,410 using the appropriate access control list 105 105 00:03:31,410 --> 00:03:33,870 and we'll talk more about access control later on 106 106 00:03:33,870 --> 00:03:35,250 as we define the four different types. 107 107 00:03:35,250 --> 00:03:36,780 But for now, just remember, 108 108 00:03:36,780 --> 00:03:39,090 you want to make sure you're enforcing access control 109 109 00:03:39,090 --> 00:03:41,250 using the appropriate ACLs. 110 110 00:03:41,250 --> 00:03:43,470 Number six, we want to restrict user accounts 111 111 00:03:43,470 --> 00:03:44,880 to the least privilege needed. 112 112 00:03:44,880 --> 00:03:47,010 You'll hear this concept a lot in security, 113 113 00:03:47,010 --> 00:03:48,720 always use least privilege. 114 114 00:03:48,720 --> 00:03:50,430 If you can do this with a user account 115 115 00:03:50,430 --> 00:03:51,990 and not use an admin account, 116 116 00:03:51,990 --> 00:03:53,610 go ahead and use a user account. 117 117 00:03:53,610 --> 00:03:56,250 If you're a user, do you need to have admin rights? 118 118 00:03:56,250 --> 00:03:58,350 No, you just need to be able to access the computer 119 119 00:03:58,350 --> 00:03:59,610 and run your systems. 120 120 00:03:59,610 --> 00:04:00,960 And so, you'll have these different things 121 121 00:04:00,960 --> 00:04:04,500 like guests and users and super users and then admins 122 122 00:04:04,500 --> 00:04:07,050 and you only want to use admin accounts when you have to 123 123 00:04:07,050 --> 00:04:08,430 because there's a high level of privilege 124 124 00:04:08,430 --> 00:04:09,263 associated with them 125 125 00:04:09,263 --> 00:04:12,000 and that would also increase your attack surface. 126 126 00:04:12,000 --> 00:04:13,440 Next, we want to look at number seven 127 127 00:04:13,440 --> 00:04:16,200 which is to secure the local admin or root account. 128 128 00:04:16,200 --> 00:04:17,490 And one of the ways to do this 129 129 00:04:17,490 --> 00:04:20,100 is by renaming it and changing the password. 130 130 00:04:20,100 --> 00:04:21,960 Everybody knows on a Linux system, 131 131 00:04:21,960 --> 00:04:23,760 the root account is called root. 132 132 00:04:23,760 --> 00:04:25,680 Everybody knows on a Windows system 133 133 00:04:25,680 --> 00:04:28,110 the administrator account is called administrator. 134 134 00:04:28,110 --> 00:04:30,240 So you should disable those two accounts 135 135 00:04:30,240 --> 00:04:32,490 and instead create another super user 136 136 00:04:32,490 --> 00:04:34,170 that is called something else. 137 137 00:04:34,170 --> 00:04:36,090 So instead of calling it administrator, 138 138 00:04:36,090 --> 00:04:38,250 I might call it Jason ADM. 139 139 00:04:38,250 --> 00:04:39,570 Or if instead of calling it root, 140 140 00:04:39,570 --> 00:04:41,340 I might call it root 123. 141 141 00:04:41,340 --> 00:04:42,390 Whatever you want to do 142 142 00:04:42,390 --> 00:04:44,040 to try to make it at least a little bit harder 143 143 00:04:44,040 --> 00:04:45,600 for the attacker is a good thing. 144 144 00:04:45,600 --> 00:04:48,480 And then, always make sure you change that default password. 145 145 00:04:48,480 --> 00:04:49,770 If you have the default password 146 146 00:04:49,770 --> 00:04:53,310 of T-O-O-R for root, which is root spelled backwards, 147 147 00:04:53,310 --> 00:04:55,620 you are going to get hacked really, really quickly. 148 148 00:04:55,620 --> 00:04:57,630 And so, you want to make sure you keep those things in mind 149 149 00:04:57,630 --> 00:04:59,550 and always change those passwords. 150 150 00:04:59,550 --> 00:05:02,550 Number eight, you want to disable unnecessary default user 151 151 00:05:02,550 --> 00:05:03,570 and group accounts. 152 152 00:05:03,570 --> 00:05:05,550 Again, if you're not using it and you don't need it, 153 153 00:05:05,550 --> 00:05:06,990 you should go ahead and disable it. 154 154 00:05:06,990 --> 00:05:08,670 This also helps harden your system 155 155 00:05:08,670 --> 00:05:10,500 and reduce your attack surface. 156 156 00:05:10,500 --> 00:05:12,540 Number nine, we want to verify permissions 157 157 00:05:12,540 --> 00:05:14,520 on system accounts and groups. 158 158 00:05:14,520 --> 00:05:16,170 This is because we can see things that happen 159 159 00:05:16,170 --> 00:05:17,160 like permission creep 160 160 00:05:17,160 --> 00:05:19,200 where people gain permissions over time 161 161 00:05:19,200 --> 00:05:21,480 and they never get those permissions taken away. 162 162 00:05:21,480 --> 00:05:24,810 For example, I worked at one company for almost a decade 163 163 00:05:24,810 --> 00:05:26,370 and every time I moved positions, 164 164 00:05:26,370 --> 00:05:28,110 they added different security controls. 165 165 00:05:28,110 --> 00:05:28,943 They said, "Oh, 166 166 00:05:28,943 --> 00:05:30,487 well now you work in accounting," for instance. 167 167 00:05:30,487 --> 00:05:32,850 "So you need access to the accounting share drives," 168 168 00:05:32,850 --> 00:05:34,140 but you might still have your access 169 169 00:05:34,140 --> 00:05:35,490 to the human resource files 170 170 00:05:35,490 --> 00:05:36,990 because you were in human resources last. 171 171 00:05:36,990 --> 00:05:38,550 And then you move over to the tech side 172 172 00:05:38,550 --> 00:05:40,380 and now you've got all three accesses. 173 173 00:05:40,380 --> 00:05:42,030 And so, what should happen is every time 174 174 00:05:42,030 --> 00:05:43,620 you move to a new department, 175 175 00:05:43,620 --> 00:05:45,390 your permissions should get taken away 176 176 00:05:45,390 --> 00:05:48,000 and only the permissions you need should be added. 177 177 00:05:48,000 --> 00:05:49,500 This is the idea of verifying permissions 178 178 00:05:49,500 --> 00:05:51,390 on the accounts and on the groups. 179 179 00:05:51,390 --> 00:05:52,800 This should also be done routinely, 180 180 00:05:52,800 --> 00:05:54,360 whether that's monthly or quarterly, 181 181 00:05:54,360 --> 00:05:55,620 against your entire system 182 182 00:05:55,620 --> 00:05:57,540 to make sure everyone has the right permissions 183 183 00:05:57,540 --> 00:05:58,950 for what they need. 184 184 00:05:58,950 --> 00:06:00,780 And number 10, you always want to make sure 185 185 00:06:00,780 --> 00:06:02,460 you're installing anti-malware software 186 186 00:06:02,460 --> 00:06:04,380 and you need to update its definitions 187 187 00:06:04,380 --> 00:06:06,360 automatically and regularly. 188 188 00:06:06,360 --> 00:06:08,070 So just having antivirus software in your computer 189 189 00:06:08,070 --> 00:06:09,060 is not good enough. 190 190 00:06:09,060 --> 00:06:11,730 It needs to check every single day for the latest updates 191 191 00:06:11,730 --> 00:06:14,280 and scheduled to automatically do its scans. 192 192 00:06:14,280 --> 00:06:16,320 This will help keep your system protected. 193 193 00:06:16,320 --> 00:06:17,520 If you do these 10 things, 194 194 00:06:17,520 --> 00:06:19,410 your system is going to be pretty strong 195 195 00:06:19,410 --> 00:06:21,030 and pretty well hardened. 196 196 00:06:21,030 --> 00:06:22,200 Now the other thing you need to consider 197 197 00:06:22,200 --> 00:06:23,760 is how are you going to harden your systems 198 198 00:06:23,760 --> 00:06:25,950 against availability attacks? 199 199 00:06:25,950 --> 00:06:28,230 Remember, we have three sides of the triangle, 200 200 00:06:28,230 --> 00:06:31,260 confidentiality, integrity and availability. 201 201 00:06:31,260 --> 00:06:32,700 Everything we just talked about 202 202 00:06:32,700 --> 00:06:35,910 was a lot to do with confidentiality and integrity. 203 203 00:06:35,910 --> 00:06:37,680 It's making sure our data is the way we want it to be 204 204 00:06:37,680 --> 00:06:39,510 and that only the right people can read it. 205 205 00:06:39,510 --> 00:06:41,730 But if we want to start focusing on availability, 206 206 00:06:41,730 --> 00:06:42,930 what can we do? 207 207 00:06:42,930 --> 00:06:43,890 If I have a server, 208 208 00:06:43,890 --> 00:06:46,170 it should be powered by an UPS or a battery backup. 209 209 00:06:46,170 --> 00:06:47,880 This will make sure that it can stay online 210 210 00:06:47,880 --> 00:06:49,980 even if the power goes down in the facility 211 211 00:06:49,980 --> 00:06:51,000 and that'll give it enough time 212 212 00:06:51,000 --> 00:06:52,530 for your secondary power to come online, 213 213 00:06:52,530 --> 00:06:54,360 which might be a generator for instance. 214 214 00:06:54,360 --> 00:06:55,980 This is the idea of how you can make sure 215 215 00:06:55,980 --> 00:06:58,260 you're protected against availability attacks 216 216 00:06:58,260 --> 00:06:59,970 that have to do with power outages. 217 217 00:06:59,970 --> 00:07:01,230 But power outages aren't the only thing 218 218 00:07:01,230 --> 00:07:02,063 we have to worry about. 219 219 00:07:02,063 --> 00:07:03,390 For instance, in my area, 220 220 00:07:03,390 --> 00:07:06,090 we have an issue with our primary internet connection. 221 221 00:07:06,090 --> 00:07:08,220 If power is out in town for more than an hour, 222 222 00:07:08,220 --> 00:07:10,020 we lose our primary internet connection. 223 223 00:07:10,020 --> 00:07:12,360 So we have a backup internet connection, 224 224 00:07:12,360 --> 00:07:13,860 we have a backup cellular modem. 225 225 00:07:13,860 --> 00:07:16,200 In addition to that, we have a backup microwave connection 226 226 00:07:16,200 --> 00:07:17,640 or a satellite connection. 227 227 00:07:17,640 --> 00:07:19,770 And so, that way, we have multiple different paths 228 228 00:07:19,770 --> 00:07:21,420 so we won't be offline. 229 229 00:07:21,420 --> 00:07:22,590 That's the idea of making sure 230 230 00:07:22,590 --> 00:07:24,840 you're protecting yourself against availability. 231 231 00:07:24,840 --> 00:07:26,850 Now, I only talked about power and internet here, 232 232 00:07:26,850 --> 00:07:28,410 but there are lots of other things 233 233 00:07:28,410 --> 00:07:29,820 that are threats to your availability 234 234 00:07:29,820 --> 00:07:30,930 and you need to think through these 235 235 00:07:30,930 --> 00:07:33,480 as you're building out your server farms and your systems 236 236 00:07:33,480 --> 00:07:34,800 because that is one of the ways 237 237 00:07:34,800 --> 00:07:36,270 you can harden those systems, 238 238 00:07:36,270 --> 00:07:37,440 is making sure they're resilient 239 239 00:07:37,440 --> 00:07:39,540 against these availability attacks. 240 240 00:07:39,540 --> 00:07:41,100 Now, the last thing I want to talk about here 241 241 00:07:41,100 --> 00:07:42,630 is the second part of this topic. 242 242 00:07:42,630 --> 00:07:43,830 We talked about hardening, 243 243 00:07:43,830 --> 00:07:45,570 now we're going to talk about patching 244 244 00:07:45,570 --> 00:07:47,850 and this comes down to patch management. 245 245 00:07:47,850 --> 00:07:49,800 Patch management involves identifying, 246 246 00:07:49,800 --> 00:07:51,690 testing and deploying operating system 247 247 00:07:51,690 --> 00:07:53,370 and application updates. 248 248 00:07:53,370 --> 00:07:55,620 As I mentioned, patches are going to be there 249 249 00:07:55,620 --> 00:07:57,600 to help you fix security bugs. 250 250 00:07:57,600 --> 00:07:59,850 When Microsoft knows there's a bug in their software, 251 251 00:07:59,850 --> 00:08:01,230 they're going to release a patch. 252 252 00:08:01,230 --> 00:08:03,570 You need to identify that you have the appropriate software 253 253 00:08:03,570 --> 00:08:04,680 that needs to be patched, 254 254 00:08:04,680 --> 00:08:06,330 you need to make sure that you test that patch 255 255 00:08:06,330 --> 00:08:07,470 before installing it, 256 256 00:08:07,470 --> 00:08:10,110 and then you need to deploy that across your network 257 257 00:08:10,110 --> 00:08:11,850 so everything gets updated. 258 258 00:08:11,850 --> 00:08:14,670 These patches are often classified as critical, 259 259 00:08:14,670 --> 00:08:17,550 security-critical, recommended and optional. 260 260 00:08:17,550 --> 00:08:19,770 If it's a critical or a security critical, 261 261 00:08:19,770 --> 00:08:22,080 you probably should make sure you get those out quicker. 262 262 00:08:22,080 --> 00:08:23,400 If it's something that's optional, 263 263 00:08:23,400 --> 00:08:25,200 you could probably wait a little while on that. 264 264 00:08:25,200 --> 00:08:27,480 And again, this all goes back to your risk appetite 265 265 00:08:27,480 --> 00:08:28,680 and risk management. 266 266 00:08:28,680 --> 00:08:30,600 Now, when you're trying to conduct patch management 267 267 00:08:30,600 --> 00:08:31,770 at the enterprise level, 268 268 00:08:31,770 --> 00:08:34,500 you're going to need some sort of patch management tool suite. 269 269 00:08:34,500 --> 00:08:36,480 There are lots of different tool suites out there, 270 270 00:08:36,480 --> 00:08:39,420 but two of the most common are made by Microsoft. 271 271 00:08:39,420 --> 00:08:42,060 Microsoft has the System Center Configuration Manager 272 272 00:08:42,060 --> 00:08:44,880 or SCCM and the Endpoint Manager, 273 273 00:08:44,880 --> 00:08:46,680 as you can see here on the screen. 274 274 00:08:46,680 --> 00:08:49,620 These are designed to support both Microsoft systems 275 275 00:08:49,620 --> 00:08:51,300 as well as having some ability 276 276 00:08:51,300 --> 00:08:53,310 to detect things on other systems as well, 277 277 00:08:53,310 --> 00:08:56,850 but really they're primarily focused on Microsoft systems. 278 278 00:08:56,850 --> 00:08:58,440 Now, one of the things you have to be aware of 279 279 00:08:58,440 --> 00:08:59,700 when you're dealing with patch management 280 280 00:08:59,700 --> 00:09:01,110 is that just patching 281 281 00:09:01,110 --> 00:09:03,360 is actually an availability risk in itself 282 282 00:09:03,360 --> 00:09:05,070 because when I install a patch, 283 283 00:09:05,070 --> 00:09:07,140 I actually can put that onto a critical system 284 284 00:09:07,140 --> 00:09:09,090 and then that system needs to be rebooted. 285 285 00:09:09,090 --> 00:09:11,880 When I do that, that might take five, 10, 15 minutes 286 286 00:09:11,880 --> 00:09:12,930 to reboot that server 287 287 00:09:12,930 --> 00:09:15,540 and that means that server is down for that time. 288 288 00:09:15,540 --> 00:09:17,430 So you need to make sure you're planning 289 289 00:09:17,430 --> 00:09:19,260 when these patches are going to go out. 290 290 00:09:19,260 --> 00:09:21,270 You can't just do it in the middle of the workday. 291 291 00:09:21,270 --> 00:09:22,950 You're going to have to have a downtime window 292 292 00:09:22,950 --> 00:09:25,080 or a maintenance window for you to be able to install 293 293 00:09:25,080 --> 00:09:26,640 those patches to critical systems 294 294 00:09:26,640 --> 00:09:29,550 if you don't have a fully redundant network that's built. 295 295 00:09:29,550 --> 00:09:31,440 Luckily, most of our organizations 296 296 00:09:31,440 --> 00:09:32,910 have moved to the cloud now. 297 297 00:09:32,910 --> 00:09:35,700 Most of us have a fully redundant network built out, 298 298 00:09:35,700 --> 00:09:37,650 so we can take a single server offline, 299 299 00:09:37,650 --> 00:09:39,630 patch it and then bring it back up. 300 300 00:09:39,630 --> 00:09:40,830 But if you're still working 301 301 00:09:40,830 --> 00:09:42,780 with some of these older legacy systems, 302 302 00:09:42,780 --> 00:09:44,880 you may have to reboot the system manually 303 303 00:09:44,880 --> 00:09:46,080 and you may not have a backup. 304 304 00:09:46,080 --> 00:09:47,910 And so, that would be an availability risk 305 305 00:09:47,910 --> 00:09:49,590 that you have to consider. 306 306 00:09:49,590 --> 00:09:51,390 Finally, when we talk about patches, 307 307 00:09:51,390 --> 00:09:53,970 you have to remember that patches don't always exist. 308 308 00:09:53,970 --> 00:09:55,200 You might have a piece of software 309 309 00:09:55,200 --> 00:09:56,400 that's really, really old 310 310 00:09:56,400 --> 00:09:58,020 or a system that's really, really old 311 311 00:09:58,020 --> 00:09:59,850 and manufacturer just doesn't even exist anymore, 312 312 00:09:59,850 --> 00:10:01,140 they've gone out of business, 313 313 00:10:01,140 --> 00:10:02,970 in which case there is no patch available. 314 314 00:10:02,970 --> 00:10:05,250 Instead, you'll have to use compensating controls. 315 315 00:10:05,250 --> 00:10:07,110 So if you're looking for patches that don't exist, 316 316 00:10:07,110 --> 00:10:09,930 things like legacy systems, proprietary systems, 317 317 00:10:09,930 --> 00:10:12,930 ICS/SCADA or Internet of Things systems and devices 318 318 00:10:12,930 --> 00:10:14,340 and you can't find it, 319 319 00:10:14,340 --> 00:10:16,710 you may have to either take that thing off the network 320 320 00:10:16,710 --> 00:10:18,570 if you can assume that business risk 321 321 00:10:18,570 --> 00:10:21,030 or you're going to put in compensating controls 322 322 00:10:21,030 --> 00:10:21,960 to overcome the fact 323 323 00:10:21,960 --> 00:10:23,970 that you can't patch that vulnerability. 324 324 00:10:23,970 --> 00:10:25,320 Now, what do I mean by this? 325 325 00:10:25,320 --> 00:10:27,180 Let's say you had an older network file system 326 326 00:10:27,180 --> 00:10:29,310 and it requires Port 445 to be open 327 327 00:10:29,310 --> 00:10:31,380 for it to be able to share those files. 328 328 00:10:31,380 --> 00:10:34,290 Well, we don't want to have port 445 open to the internet 329 329 00:10:34,290 --> 00:10:36,180 because that would be a vulnerability. 330 330 00:10:36,180 --> 00:10:37,860 So a compensating control 331 331 00:10:37,860 --> 00:10:40,860 if I can't patch this software against a given vulnerability 332 332 00:10:40,860 --> 00:10:42,540 is to make sure that this file server 333 333 00:10:42,540 --> 00:10:44,730 is only available internal to the network 334 334 00:10:44,730 --> 00:10:47,070 and I can block it from getting out of the firewall 335 335 00:10:47,070 --> 00:10:48,240 or anything outside the firewall 336 336 00:10:48,240 --> 00:10:50,010 from getting to this file server. 337 337 00:10:50,010 --> 00:10:52,260 By doing this, I put a compensating control in place 338 338 00:10:52,260 --> 00:10:54,660 such as blocking port 445 from the internet 339 339 00:10:54,660 --> 00:10:58,320 and that can solve the problem of an exploit over port 445 340 340 00:10:58,320 --> 00:11:01,120 that this older proprietary system may be vulnerable to.