1 1 00:00:00,480 --> 00:00:01,680 There is a large amount 2 2 00:00:01,680 --> 00:00:03,510 of security data that we can obtain 3 3 00:00:03,510 --> 00:00:05,340 from our various network appliances, 4 4 00:00:05,340 --> 00:00:06,690 such as our firewalls, 5 5 00:00:06,690 --> 00:00:09,210 and our intrusion detection and prevention systems. 6 6 00:00:09,210 --> 00:00:10,890 In this lesson, we're going to focus 7 7 00:00:10,890 --> 00:00:12,780 on a review of firewall logs, 8 8 00:00:12,780 --> 00:00:15,630 to determine the security posture of our networks. 9 9 00:00:15,630 --> 00:00:17,970 Now, this lesson and this course assumes 10 10 00:00:17,970 --> 00:00:18,960 that you already are familiar 11 11 00:00:18,960 --> 00:00:20,940 with the basic functions of a firewall 12 12 00:00:20,940 --> 00:00:22,710 and the basic configurations of one, 13 13 00:00:22,710 --> 00:00:24,600 because you've already taken Network Plus, 14 14 00:00:24,600 --> 00:00:27,090 and Security Plus in your past studies. 15 15 00:00:27,090 --> 00:00:28,320 As you probably remember, 16 16 00:00:28,320 --> 00:00:29,820 a firewall is designed to provide you 17 17 00:00:29,820 --> 00:00:32,430 with a line of defense at the network's boundary, 18 18 00:00:32,430 --> 00:00:33,960 to limit the types of traffic 19 19 00:00:33,960 --> 00:00:36,510 that pass in and out of a given network. 20 20 00:00:36,510 --> 00:00:39,780 It does this, usually, using an Access Control List. 21 21 00:00:39,780 --> 00:00:41,550 Now, an Access Control List is a list 22 22 00:00:41,550 --> 00:00:43,920 of permitted and denied network connections, 23 23 00:00:43,920 --> 00:00:46,470 based on either an IP address, a port, 24 24 00:00:46,470 --> 00:00:48,360 or the applications in use. 25 25 00:00:48,360 --> 00:00:50,490 As you start to analyze firewall logs, 26 26 00:00:50,490 --> 00:00:51,900 you're going to notice that they provide you 27 27 00:00:51,900 --> 00:00:54,630 with four types of useful security data. 28 28 00:00:54,630 --> 00:00:56,670 First, they provide you with connections 29 29 00:00:56,670 --> 00:00:59,010 that are either going to be permitted, or denied. 30 30 00:00:59,010 --> 00:01:01,410 You can start noticing these patterns within the logs, 31 31 00:01:01,410 --> 00:01:02,850 and this will help you identify holes 32 32 00:01:02,850 --> 00:01:04,890 within your security posture. 33 33 00:01:04,890 --> 00:01:08,040 Second, they have port and protocol usage. 34 34 00:01:08,040 --> 00:01:09,390 This is going to tell you what ports 35 35 00:01:09,390 --> 00:01:11,430 and protocols are being used in your network, 36 36 00:01:11,430 --> 00:01:12,870 which ones you want to allow, 37 37 00:01:12,870 --> 00:01:15,180 and maybe which ones you want to start blocking. 38 38 00:01:15,180 --> 00:01:18,120 Third, your logs can show you bandwidth utilization, 39 39 00:01:18,120 --> 00:01:19,590 with the duration and the volume 40 40 00:01:19,590 --> 00:01:21,780 of usage for particular connections. 41 41 00:01:21,780 --> 00:01:23,070 This way, you can break down 42 42 00:01:23,070 --> 00:01:25,560 connection by connection, user by user, 43 43 00:01:25,560 --> 00:01:28,110 department by department, or server by server, 44 44 00:01:28,110 --> 00:01:30,360 and figure out which ones you want to focus on. 45 45 00:01:30,360 --> 00:01:31,890 And fourth, they provide you 46 46 00:01:31,890 --> 00:01:34,380 with an audit log of all of the address translations, 47 47 00:01:34,380 --> 00:01:36,120 whether they're network address translation, 48 48 00:01:36,120 --> 00:01:38,520 or port address translation that have occurred 49 49 00:01:38,520 --> 00:01:39,900 within your networks. 50 50 00:01:39,900 --> 00:01:41,550 If you ever find yourself responding 51 51 00:01:41,550 --> 00:01:42,753 to an incident response, 52 52 00:01:43,813 --> 00:01:45,360 you're going to find yourself going through these firewall logs 53 53 00:01:45,360 --> 00:01:46,530 to determine which host 54 54 00:01:46,530 --> 00:01:49,170 had that particular IP at any given time, 55 55 00:01:49,170 --> 00:01:51,990 especially since so many enterprises use DHCP 56 56 00:01:51,990 --> 00:01:53,310 for their internal addressing. 57 57 00:01:53,310 --> 00:01:55,890 So, what does a firewall log look like? 58 58 00:01:55,890 --> 00:01:58,440 Well, each firewall log format is going to be different 59 59 00:01:58,440 --> 00:02:00,240 based on the vendor that you're using. 60 60 00:02:00,240 --> 00:02:02,520 Each one has its own specific format. 61 61 00:02:02,520 --> 00:02:04,560 In this course, I'm going to cover two tools, 62 62 00:02:04,560 --> 00:02:06,300 and show you what their logs look like. 63 63 00:02:06,300 --> 00:02:08,190 First, iptables. 64 64 00:02:08,190 --> 00:02:10,470 Iptables is a Linux-based firewall 65 65 00:02:10,470 --> 00:02:13,650 that uses the CIS log file format for all of its logs. 66 66 00:02:13,650 --> 00:02:14,700 This is what they look like, 67 67 00:02:14,700 --> 00:02:16,263 as you can see here on the screen. 68 68 00:02:16,263 --> 00:02:19,650 Now, as you can see, there is a lot of detail inside this 69 69 00:02:19,650 --> 00:02:22,890 and this is just two lines out of a log. 70 70 00:02:22,890 --> 00:02:25,500 Now, each of these indicates one attempted connection, 71 71 00:02:25,500 --> 00:02:26,520 either going in or out, 72 72 00:02:26,520 --> 00:02:27,960 and we're going to walk through these logs 73 73 00:02:27,960 --> 00:02:30,300 to make sure you understand how to read them. 74 74 00:02:30,300 --> 00:02:33,120 Each log entry is prefixed with a timestamp, 75 75 00:02:33,120 --> 00:02:35,820 a device ID or host name, and a facility, 76 76 00:02:35,820 --> 00:02:38,010 which is usually going to be the kernel. 77 77 00:02:38,010 --> 00:02:41,430 After that, each log rule is going to have a log prefixed value 78 78 00:02:41,430 --> 00:02:43,920 or a log level, and this will tell you 79 79 00:02:43,920 --> 00:02:46,860 which rule was being applied when this was logged. 80 80 00:02:46,860 --> 00:02:50,010 In this case, you see iptables input drop 81 81 00:02:50,010 --> 00:02:52,830 which tells me this was a drop rule that was being applied. 82 82 00:02:52,830 --> 00:02:54,840 Now in this area, sometimes you'll also have 83 83 00:02:54,840 --> 00:02:56,250 a log level value, 84 84 00:02:56,250 --> 00:02:58,290 which will tell you from zero to seven 85 85 00:02:58,290 --> 00:03:00,510 on the CIS log log scale, what it is. 86 86 00:03:00,510 --> 00:03:02,850 I'll talk about those in a little bit more later on. 87 87 00:03:02,850 --> 00:03:05,640 In this particular log, you don't see that being shown. 88 88 00:03:05,640 --> 00:03:07,050 Following this header values, 89 89 00:03:07,050 --> 00:03:10,050 we then have the actual contents of the log message. 90 90 00:03:10,050 --> 00:03:12,780 This includes a lot of attribute value pairs, 91 91 00:03:12,780 --> 00:03:16,200 each one delineated by commas or spaces. 92 92 00:03:16,200 --> 00:03:17,700 Following that header information, 93 93 00:03:17,700 --> 00:03:20,040 we are going to have a set of attribute pairs 94 94 00:03:20,040 --> 00:03:23,310 showing the attribute equals value as it goes through, 95 95 00:03:23,310 --> 00:03:26,100 and each one is going to be in a delineated format. 96 96 00:03:26,100 --> 00:03:27,930 Now, here you can see the first ones we have 97 97 00:03:27,930 --> 00:03:29,310 is our interfaces. 98 98 00:03:29,310 --> 00:03:30,330 This is going to tell us which 99 99 00:03:30,330 --> 00:03:32,340 firewall host interfaces were involved. 100 100 00:03:32,340 --> 00:03:34,620 In this case, it was an inbound interface 101 101 00:03:34,620 --> 00:03:37,530 called eth0 or Ethernet zero. 102 102 00:03:37,530 --> 00:03:39,390 There was no outbound because this was something 103 103 00:03:39,390 --> 00:03:41,490 attempting to get into our network. 104 104 00:03:41,490 --> 00:03:44,130 Next, we have which Mac addresses are involved, 105 105 00:03:44,130 --> 00:03:46,860 both the source and the destination. 106 106 00:03:46,860 --> 00:03:50,250 After that, we have the source and destination IP addresses, 107 107 00:03:50,250 --> 00:03:52,170 and this is going to be logged as well. 108 108 00:03:52,170 --> 00:03:53,340 After you have that, 109 109 00:03:53,340 --> 00:03:55,140 you're going to end up having some information 110 110 00:03:55,140 --> 00:03:56,670 about the packet itself. 111 111 00:03:56,670 --> 00:03:58,680 This will include things like it's LEN, 112 112 00:03:58,680 --> 00:04:01,200 the TOS, the precedent, the time to live, 113 113 00:04:01,200 --> 00:04:02,850 and lots of other details. 114 114 00:04:02,850 --> 00:04:06,210 You also see the protocoling use, was it TCP or UDP? 115 115 00:04:06,210 --> 00:04:07,680 You'll see what the source port was, 116 116 00:04:07,680 --> 00:04:09,030 and the destination port. 117 117 00:04:09,030 --> 00:04:10,230 You'll see the window 118 118 00:04:10,230 --> 00:04:11,523 and all the other information like that, 119 119 00:04:11,523 --> 00:04:12,720 that is important to you 120 120 00:04:12,720 --> 00:04:14,790 as you look at that packet header. 121 121 00:04:14,790 --> 00:04:16,590 Now, as we take a look at these two packets 122 122 00:04:16,590 --> 00:04:17,640 that were being dropped, 123 123 00:04:17,640 --> 00:04:18,701 the first one on the top, 124 124 00:04:18,701 --> 00:04:22,350 is actually showing a destination port of 23. 125 125 00:04:22,350 --> 00:04:25,500 So, as something was trying to come into our network, 126 126 00:04:25,500 --> 00:04:27,990 the firewall saw it was destined for port 23, 127 127 00:04:27,990 --> 00:04:30,750 which is Telnet, and said, I don't have a Telnet server, 128 128 00:04:30,750 --> 00:04:33,810 that port isn't open, and it dropped this packet. 129 129 00:04:33,810 --> 00:04:35,190 Now, the second one on the bottom, 130 130 00:04:35,190 --> 00:04:37,650 you could see as a destination port of 21. 131 131 00:04:37,650 --> 00:04:40,440 Similarly, there's no FTP server being run. 132 132 00:04:40,440 --> 00:04:43,440 This port was closed, and so the firewall is going to drop it, 133 133 00:04:43,440 --> 00:04:45,240 and reject that request. 134 134 00:04:45,240 --> 00:04:47,010 This is what it looks like when you start looking 135 135 00:04:47,010 --> 00:04:50,460 at something in iptables in the CIS log format. 136 136 00:04:50,460 --> 00:04:52,710 Now, earlier I mentioned that there was a CIS log value 137 137 00:04:52,710 --> 00:04:54,900 that could be used, anywhere from zero, 138 138 00:04:54,900 --> 00:04:57,870 which is emergency up to seven, which is debug, 139 139 00:04:57,870 --> 00:05:00,120 and here on the screen you can see all the categories, 140 140 00:05:00,120 --> 00:05:01,560 from zero to seven. 141 141 00:05:01,560 --> 00:05:03,180 This chart should be reviewed for you, 142 142 00:05:03,180 --> 00:05:06,450 because it was covered in Network Plus and Security Plus. 143 143 00:05:06,450 --> 00:05:08,820 I'm putting it here on this slide just for your reference 144 144 00:05:08,820 --> 00:05:11,470 because you may see questions about this on the exam. 145 145 00:05:12,570 --> 00:05:14,670 Now, as I said, this CIS log format 146 146 00:05:14,670 --> 00:05:16,800 is used by iptables and Linux, 147 147 00:05:16,800 --> 00:05:18,960 but what if you're using a Windows firewall? 148 148 00:05:18,960 --> 00:05:22,170 Well, Windows uses a Windows-based firewall that uses 149 149 00:05:22,170 --> 00:05:25,980 the W3C Extended Log File Format. 150 150 00:05:25,980 --> 00:05:28,020 Now, here's what this looks like. 151 151 00:05:28,020 --> 00:05:30,750 The nice thing about the Windows Firewall log format 152 152 00:05:30,750 --> 00:05:32,340 is that it is a lot easier to read 153 153 00:05:32,340 --> 00:05:34,710 because they put comment lines above it. 154 154 00:05:34,710 --> 00:05:36,120 So, it tells you right off the bat, 155 155 00:05:36,120 --> 00:05:37,350 what software are you running? 156 156 00:05:37,350 --> 00:05:41,580 In this case, the Microsoft HTTP server, API 2.0. 157 157 00:05:41,580 --> 00:05:43,410 What version of the software are you running? 158 158 00:05:43,410 --> 00:05:45,420 What was the date that this file was written? 159 159 00:05:45,420 --> 00:05:46,740 And then, what fields are there? 160 160 00:05:46,740 --> 00:05:47,610 And this is really important 161 161 00:05:47,610 --> 00:05:48,990 because this is your key 162 162 00:05:48,990 --> 00:05:51,000 to the next piece of information. 163 163 00:05:51,000 --> 00:05:52,170 As you go through the logs, 164 164 00:05:52,170 --> 00:05:54,270 that last line that you see on my screen, 165 165 00:05:54,270 --> 00:05:56,190 that is the log file itself. 166 166 00:05:56,190 --> 00:05:57,600 Now, all the information above 167 167 00:05:57,600 --> 00:06:00,030 is the beginning of that log file that shows comments, 168 168 00:06:00,030 --> 00:06:01,890 but as we start logging multiple things, 169 169 00:06:01,890 --> 00:06:02,940 we're just going to get repeats 170 170 00:06:02,940 --> 00:06:05,460 of that bottom line with the different details. 171 171 00:06:05,460 --> 00:06:07,380 So, let's go ahead and read through that. 172 172 00:06:07,380 --> 00:06:09,930 Notice that we have that commented line of fields 173 173 00:06:09,930 --> 00:06:12,630 and it tells us exactly what is being covered here. 174 174 00:06:12,630 --> 00:06:14,220 So, first we have the date 175 175 00:06:14,220 --> 00:06:18,060 and you can see the matching date, 2002-05-02. 176 176 00:06:18,060 --> 00:06:22,470 Then we have the time, in this case, 17:42 and 15 seconds. 177 177 00:06:22,470 --> 00:06:24,090 Then we have the client IP. 178 178 00:06:24,090 --> 00:06:25,950 Where was this request coming from? 179 179 00:06:25,950 --> 00:06:30,780 In this case, 172.22.255.255. 180 180 00:06:30,780 --> 00:06:33,090 Then, we have the client's username. 181 181 00:06:33,090 --> 00:06:34,740 In this case, we didn't have one, 182 182 00:06:35,610 --> 00:06:36,720 so it just shows up as a dash. 183 183 00:06:36,720 --> 00:06:38,400 Then, we have the server IP, 184 184 00:06:38,400 --> 00:06:43,400 in this case, that's 172.30.255.255, 185 185 00:06:43,530 --> 00:06:44,520 and then we have the server port 186 186 00:06:44,520 --> 00:06:47,400 we're trying to connect to, in this case, port 80. 187 187 00:06:47,400 --> 00:06:48,810 Then, we have the method, 188 188 00:06:48,810 --> 00:06:50,880 and this is going to be the client method that was used, 189 189 00:06:50,880 --> 00:06:52,950 in this case, it was the GET method, 190 190 00:06:52,950 --> 00:06:54,540 which we talked about in a previous lesson 191 191 00:06:54,540 --> 00:06:57,090 when we talked about the HTTP methods. 192 192 00:06:57,090 --> 00:06:59,820 After that, we have the client URI stem 193 193 00:06:59,820 --> 00:07:02,670 and this is what resource was it trying to access? 194 194 00:07:02,670 --> 00:07:05,310 In this case, it was the picture JPG file 195 195 00:07:05,310 --> 00:07:07,440 inside the images directory, 196 196 00:07:07,440 --> 00:07:09,960 and then we have the CS URI query, 197 197 00:07:09,960 --> 00:07:11,580 and in this case, it has a dash, 198 198 00:07:11,580 --> 00:07:13,290 because there was no query being made. 199 199 00:07:13,290 --> 00:07:15,390 If we were using something like a post method instead, 200 200 00:07:15,390 --> 00:07:16,890 we would have a query associated with it, 201 201 00:07:16,890 --> 00:07:18,540 and that would be shown here. 202 202 00:07:18,540 --> 00:07:20,430 And then we have our SC status, 203 203 00:07:20,430 --> 00:07:23,010 and if you remember, back in our HTTP lesson, 204 204 00:07:23,010 --> 00:07:24,600 we talked about the fact that 200 205 205 00:07:24,600 --> 00:07:27,510 meant it was okay, it was a successful status. 206 206 00:07:27,510 --> 00:07:30,420 So, this tells me this get request actually worked. 207 207 00:07:30,420 --> 00:07:32,280 They were able to access that server, 208 208 00:07:32,280 --> 00:07:35,070 and get that file that they wanted and have it downloaded. 209 209 00:07:35,070 --> 00:07:36,810 The final thing we have is what's called 210 210 00:07:36,810 --> 00:07:38,430 our client user agent, 211 211 00:07:38,430 --> 00:07:40,800 and this is that long string there, at the bottom. 212 212 00:07:40,800 --> 00:07:41,910 This is Mozilla, 213 213 00:07:41,910 --> 00:07:43,890 and then it tells us some information about it. 214 214 00:07:43,890 --> 00:07:45,030 So, by reading this, I know 215 215 00:07:45,030 --> 00:07:46,650 that they're using the Mozilla browser. 216 216 00:07:46,650 --> 00:07:48,930 In this case, it's most likely Firefox, 217 217 00:07:48,930 --> 00:07:49,977 and it also tells me what type 218 218 00:07:49,977 --> 00:07:51,600 of client it was used on, 219 219 00:07:51,600 --> 00:07:53,730 in this case, Windows 2000 server. 220 220 00:07:53,730 --> 00:07:54,690 This gives me some details 221 221 00:07:54,690 --> 00:07:56,640 about the client that was actually accessing this, 222 222 00:07:56,640 --> 00:07:59,490 and going through the firewall, making this attempt. 223 223 00:07:59,490 --> 00:08:00,810 So, before we go any further, 224 224 00:08:00,810 --> 00:08:02,190 I want to take a quick pause 225 225 00:08:02,190 --> 00:08:04,770 and talk about a quick exam tip for you. 226 226 00:08:04,770 --> 00:08:06,810 For the exam, you should be comfortable 227 227 00:08:06,810 --> 00:08:08,550 reading these types of logs. 228 228 00:08:08,550 --> 00:08:10,980 You need to be able to understand what has occurred. 229 229 00:08:10,980 --> 00:08:14,070 For example, if on the exam they give you five to 10 lines 230 230 00:08:14,070 --> 00:08:15,750 from the Windows firewall log, 231 231 00:08:15,750 --> 00:08:16,583 you should be able to tell 232 232 00:08:16,583 --> 00:08:18,750 if the client requested a file from the server, 233 233 00:08:18,750 --> 00:08:20,520 if that request was successful. 234 234 00:08:20,520 --> 00:08:23,370 For example, did they get that status code 200? 235 235 00:08:23,370 --> 00:08:25,500 Or if a post request was successful, 236 236 00:08:25,500 --> 00:08:27,390 to send a file to a remote server. 237 237 00:08:27,390 --> 00:08:29,220 You don't have to be a firewall expert here, 238 238 00:08:29,220 --> 00:08:31,110 but you do have to have a solid understanding 239 239 00:08:31,110 --> 00:08:32,730 of reading these iptable logs, 240 240 00:08:32,730 --> 00:08:34,410 and these Windows Firewall logs 241 241 00:08:34,410 --> 00:08:35,880 because that is going to be essential to you 242 242 00:08:35,880 --> 00:08:38,190 passing the CYSA Plus exam. 243 243 00:08:38,190 --> 00:08:40,380 All right, so we have all these log files, 244 244 00:08:40,380 --> 00:08:42,450 and we start collecting a ton of data. 245 245 00:08:42,450 --> 00:08:43,560 What do we do with it? 246 246 00:08:43,560 --> 00:08:44,880 Well, the first thing you should do 247 247 00:08:44,880 --> 00:08:46,950 is employ a log collection tool 248 248 00:08:46,950 --> 00:08:48,330 to gather the large volume 249 249 00:08:48,330 --> 00:08:50,790 of firewall logs for later analysis. 250 250 00:08:50,790 --> 00:08:53,070 You can't have them sitting on one single machine, 251 251 00:08:53,070 --> 00:08:55,800 because if that machine goes down, you lose all the logs. 252 252 00:08:55,800 --> 00:08:59,130 Also, a single machine probably can't hold all these logs, 253 253 00:08:59,130 --> 00:09:01,440 because there's so much data here. 254 254 00:09:01,440 --> 00:09:02,490 Now, one of the big things 255 255 00:09:02,490 --> 00:09:05,070 is that you can become overloaded with information, 256 256 00:09:05,070 --> 00:09:07,530 and so you have to scope your logging properly. 257 257 00:09:07,530 --> 00:09:09,510 How much do you really want to log? 258 258 00:09:09,510 --> 00:09:11,190 What is the important things to log? 259 259 00:09:11,190 --> 00:09:12,810 Where are you going to place these sensors, 260 260 00:09:12,810 --> 00:09:14,550 and where are you going to place these firewalls 261 261 00:09:14,550 --> 00:09:17,280 to collect the information and provide the best protection? 262 262 00:09:17,280 --> 00:09:19,084 These are all things you have to think about. 263 263 00:09:19,084 --> 00:09:20,610 If you don't think about this, 264 264 00:09:20,610 --> 00:09:22,440 and you don't scope your logging properly, 265 265 00:09:22,440 --> 00:09:24,210 and you try to log everything, 266 266 00:09:24,210 --> 00:09:26,190 you may become overloaded with events, 267 267 00:09:26,190 --> 00:09:28,680 and it makes it really hard to analyze later, 268 268 00:09:28,680 --> 00:09:31,560 or your system can actually be blinded, 269 269 00:09:31,560 --> 00:09:33,810 and this is known as a blinding attack. 270 270 00:09:33,810 --> 00:09:36,000 Now, a blinding attack is a condition that occurs 271 271 00:09:36,000 --> 00:09:38,070 when a firewall is under-resourced, 272 272 00:09:38,070 --> 00:09:40,500 and it simply can't log all the data fast enough, 273 273 00:09:40,500 --> 00:09:42,120 and therefore some of that data 274 274 00:09:42,120 --> 00:09:43,320 is going to be missing in the logs, 275 275 00:09:43,320 --> 00:09:45,240 and you're not going to be able to analyze it later. 276 276 00:09:45,240 --> 00:09:46,440 Another thing you have to determine 277 277 00:09:46,440 --> 00:09:48,810 is how long you're going to retain these logs. 278 278 00:09:48,810 --> 00:09:50,340 Log retention should be determined 279 279 00:09:50,340 --> 00:09:52,440 by the number of events that are being generated, 280 280 00:09:52,440 --> 00:09:54,480 and your available storage capacity. 281 281 00:09:54,480 --> 00:09:56,100 But it also has to be determined based 282 282 00:09:56,100 --> 00:09:57,300 on your business case. 283 283 00:09:57,300 --> 00:09:59,310 And if you have a business case to keep all these logs, 284 284 00:09:59,310 --> 00:10:01,200 then you may need to buy more storage capacity 285 285 00:10:01,200 --> 00:10:02,760 to be able to handle that. 286 286 00:10:02,760 --> 00:10:05,430 For example, if you've been attacked in the past, 287 287 00:10:05,430 --> 00:10:07,410 and you won't be able to go back and look at that, 288 288 00:10:07,410 --> 00:10:08,910 if you don't have long-term retention, 289 289 00:10:08,910 --> 00:10:10,410 you're not going to be able to do that. 290 290 00:10:10,410 --> 00:10:12,720 So, some companies might say they're only going to keep logs 291 291 00:10:12,720 --> 00:10:14,760 for three months, some say six months, 292 292 00:10:14,760 --> 00:10:17,460 some say 12 months, some say forever. 293 293 00:10:17,460 --> 00:10:19,110 It really depends on your organization 294 294 00:10:19,110 --> 00:10:20,850 and what you're willing to spend. 295 295 00:10:20,850 --> 00:10:23,070 Now, if you have the threat of an APT, 296 296 00:10:23,070 --> 00:10:25,980 remember on average, an APT can be in your network 297 297 00:10:25,980 --> 00:10:27,900 for five, six or seven months 298 298 00:10:27,900 --> 00:10:30,000 before you ever determine they're there, 299 299 00:10:30,000 --> 00:10:31,710 and that means you probably need to keep your logs 300 300 00:10:31,710 --> 00:10:33,300 at least 6 to 12 months, 301 301 00:10:33,300 --> 00:10:35,250 so you have a chance of finding out how they got in, 302 302 00:10:35,250 --> 00:10:37,230 and how you can stop them for next time. 303 303 00:10:37,230 --> 00:10:39,000 Now, I get asked a lot by students, 304 304 00:10:39,000 --> 00:10:41,010 how do I practice this stuff, Jason? 305 305 00:10:41,010 --> 00:10:42,690 Where can I find log files? 306 306 00:10:42,690 --> 00:10:44,220 Well, one of the best things to do 307 307 00:10:44,220 --> 00:10:46,260 is actually set up your own firewall 308 308 00:10:46,260 --> 00:10:47,670 in your home network. 309 309 00:10:47,670 --> 00:10:50,880 This way you can turn it on and start analyzing those files, 310 310 00:10:50,880 --> 00:10:51,810 and if you want to do this, 311 311 00:10:51,810 --> 00:10:54,330 there's a great tool called PF Sense. 312 312 00:10:54,330 --> 00:10:56,460 PF Sense is a Unified Threat Manager 313 313 00:10:56,460 --> 00:10:57,930 which contains a firewall, 314 314 00:10:57,930 --> 00:11:00,090 and it is a free open-source program. 315 315 00:11:00,090 --> 00:11:02,277 You could take an old laptop or an old desktop, 316 316 00:11:02,277 --> 00:11:06,060 install PF Sense on it and run it to protect your network. 317 317 00:11:06,060 --> 00:11:08,310 Also, you'll be able to log that information, 318 318 00:11:08,310 --> 00:11:09,330 go through those logs, 319 319 00:11:09,330 --> 00:11:11,070 and be able to determine what they look like, 320 320 00:11:11,070 --> 00:11:12,660 and get comfortable reading them. 321 321 00:11:12,660 --> 00:11:13,650 There is nothing better 322 322 00:11:13,650 --> 00:11:15,990 than reading real world logs to get a real sense 323 323 00:11:15,990 --> 00:11:17,550 of what's going on out there 324 324 00:11:17,550 --> 00:11:20,500 and really get yourself better at doing this, for the exam.