1 00:00:05,990 --> 00:00:13,580 When does log on procedure is critical for System Security the Emmis Gina DL system library is used 2 00:00:13,580 --> 00:00:17,950 for logging in. 3 00:00:18,110 --> 00:00:19,420 This is worth taking note of. 4 00:00:19,420 --> 00:00:25,850 Since there's a rogue version of the file available on the Internet cold for example fake ass Gina got 5 00:00:26,020 --> 00:00:28,940 DSL. 6 00:00:28,960 --> 00:00:36,460 This means that if you replace M-S Gina DSL with fake messaging a DSL or similar files or user will 7 00:00:36,460 --> 00:00:44,840 not be able to tell a difference with a log on the logon screen would look the same but apart from submitting 8 00:00:44,840 --> 00:00:51,320 the log in and password to a security subsystem the default security services provider the credentials 9 00:00:51,320 --> 00:00:57,280 will also be saved to a txt file and forwarded to an attacker. 10 00:00:57,300 --> 00:01:02,070 Remember that log ons are simply a technology and there has to be a file that governs it 11 00:01:06,830 --> 00:01:11,480 by default cryptographic services provider in the newer Windows systems is Kerberos 12 00:01:14,030 --> 00:01:20,300 the services by a large margin the most secure method for approving user identity. 13 00:01:20,340 --> 00:01:28,460 There are in fact no documented attacks targeting Kerberos except for some peculiar cases Kerberos strength 14 00:01:28,460 --> 00:01:30,540 is that it doesn't reuse your password 15 00:01:33,150 --> 00:01:40,860 LAN Manager and LAN Manager both constantly reuse your password hash to encrypt some data network credentials 16 00:01:42,430 --> 00:01:50,530 Kerberos uses a ticket instead a ticket is valid 10 hours by default. 17 00:01:50,540 --> 00:01:55,810 This means in effect that we can change the password every 10 hours. 18 00:01:55,830 --> 00:02:03,360 Unfortunately Kerberos may sometimes be unable to authenticate a user if it can't prove a user identity. 19 00:02:03,380 --> 00:02:09,320 The system will automatically fall back to older cryptographic services provider and the land manager 20 00:02:11,510 --> 00:02:15,610 in Windows Vista and later LAN Manager is disabled by default. 21 00:02:16,910 --> 00:02:25,000 We'll find out that it was high time for that. 22 00:02:25,060 --> 00:02:29,020 If you log on to a local computer your credentials don't leave that computer 23 00:02:31,660 --> 00:02:34,080 even if you're connected to an untrusted network. 24 00:02:34,270 --> 00:02:41,420 There's no way for a would be attacker to eavesdrop on your credentials logon is a protected process 25 00:02:41,420 --> 00:02:48,590 that involves comparing the entered password against the contents of the security account manager database. 26 00:02:48,640 --> 00:02:53,500 The Windows system does contains three important files. 27 00:02:53,520 --> 00:03:00,680 The first is the same file which contains your credentials and passwords and passwords and cached credentials 28 00:03:03,160 --> 00:03:06,240 a local computer knows the credentials and can authenticate you 29 00:03:11,030 --> 00:03:14,820 remote authentication is performed differently. 30 00:03:14,950 --> 00:03:21,550 If you don't work in a domain if there's no central user credentials database an active directory database 31 00:03:22,300 --> 00:03:29,940 the same Sam files will be used to connect one computer to another one a trust relationship has not 32 00:03:29,940 --> 00:03:31,460 been established. 33 00:03:31,500 --> 00:03:37,370 You need to provide account credentials that are valid for your computer. 34 00:03:37,390 --> 00:03:41,210 There's a problem on the horizon already. 35 00:03:41,230 --> 00:03:48,630 How do you send confidential data a password over an untrusted medium and untrusted network. 36 00:03:50,120 --> 00:03:54,810 It turns out that a password is never sent over a network in clear text. 37 00:03:55,000 --> 00:03:56,740 It's used for encrypting other data 38 00:04:00,900 --> 00:04:06,180 the above diagram shows the network principle behind the first version of the end TLM protocol. 39 00:04:07,330 --> 00:04:14,570 There are two versions of NC alone this authentication method involves exchanging challenge in response 40 00:04:14,570 --> 00:04:15,290 messages 41 00:04:17,940 --> 00:04:22,010 the algorithm used for that purpose was considered secure several years ago. 42 00:04:23,710 --> 00:04:32,970 The data encryption standard was developed in the 70s today and the algorithm is anything but secure. 43 00:04:33,020 --> 00:04:40,520 There are devices that crack the ciphertext in real time when they're sent over a network. 44 00:04:40,640 --> 00:04:42,980 The procedure looks as follows. 45 00:04:43,220 --> 00:04:52,900 We a client would like to authenticate in a server a client sends an authentication request the response 46 00:04:52,900 --> 00:05:02,670 to this request is a challenge a pseudo random stream a client encrypts this challenge using a password. 47 00:05:02,730 --> 00:05:07,320 The first version of entail M will always send two responses. 48 00:05:07,570 --> 00:05:12,660 The first will be the same challenge encrypted using an L and password. 49 00:05:12,730 --> 00:05:16,810 The second response is the challenge encrypted using an empty password. 50 00:05:16,810 --> 00:05:19,350 Both messages will use encryption 51 00:05:22,300 --> 00:05:28,220 since the server same database contains our password and at least one of the entier L.M. hashes. 52 00:05:28,300 --> 00:05:32,770 It's enough to decrypt the challenge message and check it against the original message we forwarded. 53 00:05:34,630 --> 00:05:35,390 If they match. 54 00:05:35,410 --> 00:05:42,880 We're sure that the encryption used the correct password is equivalent with successful authentication 55 00:05:45,240 --> 00:05:45,870 theoretically. 56 00:05:45,870 --> 00:05:47,490 This is a great solution. 57 00:05:49,680 --> 00:05:54,270 Passwords won't be thrown into a network and were authenticated remotely. 58 00:05:54,290 --> 00:05:59,220 The problem is in the details as it often is. 59 00:05:59,410 --> 00:06:04,930 In this case the issue lies in the L-N password generating mechanism. 60 00:06:04,980 --> 00:06:07,330 We'll examine this in the next part of the module. 61 00:06:10,350 --> 00:06:16,670 L.N. version 2 is a lot more secure this tightened security is due to not sending a response that is 62 00:06:16,670 --> 00:06:26,150 encrypted using an and password the authentication does not use any L.N. hashes at all other steps in 63 00:06:26,150 --> 00:06:31,440 the procedure are quite similar although there is more randomness. 64 00:06:31,460 --> 00:06:35,480 The second version of TLM supports mut. authentication to a degree 65 00:06:41,960 --> 00:06:46,280 although authenticating to Windows networks using the L-M protocol is feasible. 66 00:06:46,280 --> 00:06:52,020 You shouldn't normally fall back on this under any circumstances. 67 00:06:52,040 --> 00:06:59,390 The second method is an TLM which also shouldn't be the preferred authentication. 68 00:06:59,420 --> 00:07:07,090 Even the oldest versions of Windows use today support the second version of NCM and TLM version 2 does 69 00:07:07,090 --> 00:07:14,590 provide some security during one of the next case studies will show you that the security is very basic 70 00:07:18,810 --> 00:07:21,990 a better way to ensure authentication security is using Kerberos. 71 00:07:21,990 --> 00:07:24,990 Version 5 instead of anti-oil and version 2. 72 00:07:27,190 --> 00:07:33,390 You could ask what makes the L.M. and the TLM protocols so on secure and why they're still used. 73 00:07:36,830 --> 00:07:42,050 The answer to the first question will be answered later will deal with the latter now. 74 00:07:43,100 --> 00:07:49,580 To authenticate using Kerberos you need to be able to reach a key distribution center a domain controller 75 00:07:51,470 --> 00:07:58,360 This functionality is supported only in the active directory domains or user may want to log on to a 76 00:07:58,360 --> 00:08:02,740 computer that is not connected to a network. 77 00:08:02,800 --> 00:08:08,590 If not for A.I.M. version 2 windows Logans would not be possible if a system can't reach any domain 78 00:08:08,590 --> 00:08:11,930 controller. 79 00:08:11,940 --> 00:08:14,640 The price for absolute security would be too high. 80 00:08:15,820 --> 00:08:20,970 So anti-law version 2 is and will continue to be implemented in Windows for some time.