1 1 00:00:00,630 --> 00:00:02,670 Unauthorized Software. 2 2 00:00:02,670 --> 00:00:05,250 Unauthorized software is one of the most obvious 3 3 00:00:05,250 --> 00:00:07,320 IOCs that you can encounter. 4 4 00:00:07,320 --> 00:00:09,570 Essentially, you find some piece of software 5 5 00:00:09,570 --> 00:00:10,800 that shouldn't be there. 6 6 00:00:10,800 --> 00:00:13,560 It could be a worm, a virus, a Trojan, 7 7 00:00:13,560 --> 00:00:15,360 or any other kind of malware. 8 8 00:00:15,360 --> 00:00:17,820 If you see this and you get a malware alert, 9 9 00:00:17,820 --> 00:00:18,960 this is an indicator 10 10 00:00:18,960 --> 00:00:21,270 that something is there that shouldn't be, 11 11 00:00:21,270 --> 00:00:23,580 and this is unauthorized software. 12 12 00:00:23,580 --> 00:00:26,730 Now, in addition to these obvious examples of malware, 13 13 00:00:26,730 --> 00:00:29,310 there are more subtle software-based indicators 14 14 00:00:29,310 --> 00:00:31,440 of compromise that could involve the presence 15 15 00:00:31,440 --> 00:00:33,780 of attack tools on a given system, 16 16 00:00:33,780 --> 00:00:35,850 because a lot of the attack tools that are out there 17 17 00:00:35,850 --> 00:00:38,550 are actually used by system administrators as well. 18 18 00:00:38,550 --> 00:00:40,830 For example, we've talked about Netcat before, 19 19 00:00:40,830 --> 00:00:43,980 we've talked about Nmap before, and Wireshark. 20 20 00:00:43,980 --> 00:00:45,330 All of these are tools that can be used 21 21 00:00:45,330 --> 00:00:47,040 by an analyst or an administrator, 22 22 00:00:47,040 --> 00:00:49,080 but they can also be used by an attacker. 23 23 00:00:49,080 --> 00:00:50,280 So when you find them, 24 24 00:00:50,280 --> 00:00:53,280 you have to determine are they authorized or not? 25 25 00:00:53,280 --> 00:00:55,770 And if they aren't, that could be an indicator of compromise 26 26 00:00:55,770 --> 00:00:58,440 of that system that some attacker's now put new tools 27 27 00:00:58,440 --> 00:01:00,690 on that system for them to use. 28 28 00:01:00,690 --> 00:01:03,180 Now, unauthorized software doesn't always have to mean 29 29 00:01:03,180 --> 00:01:06,060 some kind of malware or admin tool. 30 30 00:01:06,060 --> 00:01:07,260 It can just be software 31 31 00:01:07,260 --> 00:01:10,050 that a user isn't permitted to install themself. 32 32 00:01:10,050 --> 00:01:12,330 For example, unauthorized software can include 33 33 00:01:12,330 --> 00:01:14,430 legitimate software that shouldn't be installed 34 34 00:01:14,430 --> 00:01:16,320 on a particular workstation. 35 35 00:01:16,320 --> 00:01:18,750 In one company I worked at, we had a lot of users 36 36 00:01:18,750 --> 00:01:20,820 who would want a particular piece of software, 37 37 00:01:20,820 --> 00:01:24,180 maybe something like Adobe Acrobat or Microsoft Visio, 38 38 00:01:24,180 --> 00:01:25,650 and if we didn't provide it for them, 39 39 00:01:25,650 --> 00:01:27,810 they would go to the store, buy it themself, 40 40 00:01:27,810 --> 00:01:29,790 and then try to install it on the computer. 41 41 00:01:29,790 --> 00:01:31,440 Now, if they were successful in doing that, 42 42 00:01:31,440 --> 00:01:33,600 that is technically unauthorized software, 43 43 00:01:33,600 --> 00:01:34,590 because they weren't approved 44 44 00:01:34,590 --> 00:01:36,510 to install it on that workstation. 45 45 00:01:36,510 --> 00:01:37,860 And now the big problem with this 46 46 00:01:37,860 --> 00:01:40,020 isn't that that piece of software was bad, 47 47 00:01:40,020 --> 00:01:42,510 but it now introduces new vulnerabilities, 48 48 00:01:42,510 --> 00:01:44,760 because we have to know it's there so we can patch it 49 49 00:01:44,760 --> 00:01:47,430 and update it and make sure we have a valid license for it 50 50 00:01:47,430 --> 00:01:48,960 and all of those type of things. 51 51 00:01:48,960 --> 00:01:50,610 So all of those things are things you have to consider 52 52 00:01:50,610 --> 00:01:52,920 as well when you're dealing with software. 53 53 00:01:52,920 --> 00:01:55,710 Another area of concern is if users start installing 54 54 00:01:55,710 --> 00:01:58,290 other services on their machines. 55 55 00:01:58,290 --> 00:02:01,080 For example, Apache may be an authorized 56 56 00:02:01,080 --> 00:02:03,810 piece of software for you to install on a web server, 57 57 00:02:03,810 --> 00:02:06,540 but does that mean that everyone in the organization 58 58 00:02:06,540 --> 00:02:08,610 should be able to install Apache on their workstation 59 59 00:02:08,610 --> 00:02:10,410 and run their own web server? 60 60 00:02:10,410 --> 00:02:11,880 Well, of course not. 61 61 00:02:11,880 --> 00:02:13,500 That would be silly, because it would be something 62 62 00:02:13,500 --> 00:02:15,600 that would be a big glaring vulnerability. 63 63 00:02:15,600 --> 00:02:16,980 So as we're scanning our network 64 64 00:02:16,980 --> 00:02:18,900 and looking for different pieces of software, 65 65 00:02:18,900 --> 00:02:20,880 these are the kind of things we're looking for, 66 66 00:02:20,880 --> 00:02:23,490 things that are out of place, things that are not authorized 67 67 00:02:23,490 --> 00:02:26,460 and shouldn't be out there on those given workstations. 68 68 00:02:26,460 --> 00:02:27,840 Now, another thing an attacker can do 69 69 00:02:27,840 --> 00:02:31,050 is they can modify normal files for malicious use. 70 70 00:02:31,050 --> 00:02:34,320 For example, think about your host file on a computer. 71 71 00:02:34,320 --> 00:02:36,330 If you think back to your A+ studies, 72 72 00:02:36,330 --> 00:02:40,170 you'll remember that a host file is essentially a local DNS. 73 73 00:02:40,170 --> 00:02:42,210 So if I modify that host file 74 74 00:02:42,210 --> 00:02:45,930 and I change youtube.com to a particular IP address, 75 75 00:02:45,930 --> 00:02:49,350 it's always going to trust the host file over the DNS server. 76 76 00:02:49,350 --> 00:02:52,440 It checks there first, and so I can actually bypass 77 77 00:02:52,440 --> 00:02:55,380 you going to a valid DNS server by using your host file 78 78 00:02:55,380 --> 00:02:57,027 and modifying it as an attacker. 79 79 00:02:57,027 --> 00:02:59,760 And so this is something to keep in mind as well. 80 80 00:02:59,760 --> 00:03:02,040 As you conduct the analysis of a workstation, 81 81 00:03:02,040 --> 00:03:05,070 you're going to come across a lot of different files out there, 82 82 00:03:05,070 --> 00:03:06,450 and a lot of different file types 83 83 00:03:06,450 --> 00:03:08,820 based on the applications that are installed. 84 84 00:03:08,820 --> 00:03:10,620 Now, to look at these, you're going to have to use 85 85 00:03:10,620 --> 00:03:13,110 an application viewer in some cases. 86 86 00:03:13,110 --> 00:03:16,410 Most of your forensic toolkits, such as Encase shown here, 87 87 00:03:16,410 --> 00:03:19,650 can go in and read a lot of these different file formats. 88 88 00:03:19,650 --> 00:03:22,290 For example, here I'm looking at the webcache 89 89 00:03:22,290 --> 00:03:24,180 for a particular internet browser. 90 90 00:03:24,180 --> 00:03:25,470 This allows me to go into that 91 91 00:03:25,470 --> 00:03:28,710 and I can see what has been cashed and what has been viewed 92 92 00:03:28,710 --> 00:03:32,250 by that user with that web browser by going through it. 93 93 00:03:32,250 --> 00:03:34,440 In addition to that, it will allow me to go through 94 94 00:03:34,440 --> 00:03:36,480 and look at lots of different pieces of information 95 95 00:03:36,480 --> 00:03:38,400 and create a timeline from it. 96 96 00:03:38,400 --> 00:03:40,890 These application viewers can allow you to go in 97 97 00:03:40,890 --> 00:03:43,500 and look for different types of applications and files, 98 98 00:03:43,500 --> 00:03:45,600 such as browser histories and cookies, 99 99 00:03:45,600 --> 00:03:49,140 examining contact databases, looking at email mailboxes, 100 100 00:03:49,140 --> 00:03:52,503 or even extracting histories of calls from VoIP software. 101 101 00:03:53,400 --> 00:03:55,530 As I said, most forensic toolkits 102 102 00:03:55,530 --> 00:03:58,020 can view application usage and history, 103 103 00:03:58,020 --> 00:04:00,540 so if you're using something like Encase or FTK, 104 104 00:04:00,540 --> 00:04:03,150 or even the Sleuth toolkit, they have this capability 105 105 00:04:03,150 --> 00:04:05,730 and it makes your job a lot easier. 106 106 00:04:05,730 --> 00:04:06,960 Another thing we have to consider 107 107 00:04:06,960 --> 00:04:09,480 in our analysis is prefetch files. 108 108 00:04:09,480 --> 00:04:12,180 Now, prefetch files are files that record the names 109 109 00:04:12,180 --> 00:04:14,190 of applications that have been run, 110 110 00:04:14,190 --> 00:04:17,460 as well as the date and time, the file path, the run count, 111 111 00:04:17,460 --> 00:04:20,490 and the DLLs that were used by the executable. 112 112 00:04:20,490 --> 00:04:22,590 This is a treasure trove of information 113 113 00:04:22,590 --> 00:04:24,360 for the cybersecurity analyst, 114 114 00:04:24,360 --> 00:04:27,270 because these prefetch files have a lot of information 115 115 00:04:27,270 --> 00:04:30,390 about what has been done as you ran this executable. 116 116 00:04:30,390 --> 00:04:32,820 And so if you are running some kind of a piece of malware, 117 117 00:04:32,820 --> 00:04:34,140 you can get a lot of information 118 118 00:04:34,140 --> 00:04:35,943 from these prefetch files as well. 119 119 00:04:36,930 --> 00:04:38,910 Now, in addition to those prefetch files, 120 120 00:04:38,910 --> 00:04:41,400 you also want to look at the shimcache. 121 121 00:04:41,400 --> 00:04:44,460 Now, a shimcache is an application usage cache 122 122 00:04:44,460 --> 00:04:46,740 that is stored as a registry key. 123 123 00:04:46,740 --> 00:04:49,290 This allows you to go in and use this as an artifact 124 124 00:04:49,290 --> 00:04:51,000 as you're generating a timeline 125 125 00:04:51,000 --> 00:04:52,230 and you're trying to figure out exactly 126 126 00:04:52,230 --> 00:04:54,870 what happened when on a given system. 127 127 00:04:54,870 --> 00:04:56,400 If you're looking for the shimcache, 128 128 00:04:56,400 --> 00:05:00,680 you can find it at HKLM/SYSTEM/CurrentControlSet 129 129 00:05:00,680 --> 00:05:05,680 /Control/SessionManager/AppCompatCache 130 130 00:05:06,087 --> 00:05:08,460 /AppCompatCache. 131 131 00:05:08,460 --> 00:05:11,370 Now, I know that's really long and complicated. 132 132 00:05:11,370 --> 00:05:14,430 You do not need to memorize that location for the exam, 133 133 00:05:14,430 --> 00:05:16,860 but in the real world, it is something helpful 134 134 00:05:16,860 --> 00:05:19,050 and something you should be familiar with. 135 135 00:05:19,050 --> 00:05:22,230 The last one we want to talk about is the Amcache. 136 136 00:05:22,230 --> 00:05:24,900 Now, Amcache is an application usage cache 137 137 00:05:24,900 --> 00:05:27,600 that's stored as a hive file, and you can find this 138 138 00:05:27,600 --> 00:05:30,330 on the C drive under the Windows directory, 139 139 00:05:30,330 --> 00:05:35,330 /appcompat/Programs/Amcache.hve. 140 140 00:05:35,940 --> 00:05:38,820 Again, this is a hive file, and so it can't be opened 141 141 00:05:38,820 --> 00:05:41,310 by the reg edit tool, but it can be inspected 142 142 00:05:41,310 --> 00:05:45,573 by different file system forensic tools like Encase and FTK.