1 00:00:16,040 --> 00:00:22,190 In the last video we discussed about the past two attacks in this video, we are going to discuss about 2 00:00:22,190 --> 00:00:29,570 the two attacks and the attack attempts to alter system resources or affect their operations. 3 00:00:30,650 --> 00:00:36,950 An attack involves some modification of datastream or creation of false statements, types of attacks, 4 00:00:36,950 --> 00:00:41,360 a masquerade repudiation, ripply and denial of service. 5 00:00:43,070 --> 00:00:49,880 The first attack is muscular, muscular attack takes place within one entity, pretends to be a different 6 00:00:49,880 --> 00:00:50,270 entity. 7 00:00:51,080 --> 00:00:55,550 Consider the same three characters, Bob Ellis and Judy here. 8 00:00:55,880 --> 00:00:57,500 Bob since Mr. to Alice. 9 00:00:58,040 --> 00:00:58,730 Hey, Alice. 10 00:00:59,030 --> 00:00:59,780 It's me, Bob. 11 00:01:00,030 --> 00:01:00,770 How are you? 12 00:01:01,490 --> 00:01:04,100 Alice replies, Hey, Bob, I'm fine. 13 00:01:04,250 --> 00:01:04,830 What's up? 14 00:01:05,030 --> 00:01:12,140 But in this case, the Trudy, who is the interceptor, impersonates Bob and sends a message to Alice. 15 00:01:12,680 --> 00:01:14,960 How about Robert at 5:00 p.m.? 16 00:01:15,470 --> 00:01:20,810 This message is not sent through, Bob, but this message is sent to Trudy. 17 00:01:21,170 --> 00:01:22,430 Who is the intruder? 18 00:01:23,510 --> 00:01:26,090 Alice replies, Okay, Bob then. 19 00:01:26,690 --> 00:01:30,940 And this creates a confusion which lets Alice into trouble. 20 00:01:31,460 --> 00:01:33,260 This is called as the masquerade attack. 21 00:01:34,370 --> 00:01:41,320 Next is the replay, and it involves the best capture of a message and subsequent transmission to produce 22 00:01:41,330 --> 00:01:42,500 an opposite effect. 23 00:01:43,430 --> 00:01:47,570 Consider the scenario, Bob Ellis and Judy here. 24 00:01:47,840 --> 00:01:49,890 Bob, since Mesoscale is here. 25 00:01:50,410 --> 00:01:53,590 Let's meet today at six p.m. a little place. 26 00:01:53,780 --> 00:01:54,400 Hey, Bob. 27 00:01:54,470 --> 00:01:54,730 OK. 28 00:01:55,610 --> 00:02:00,080 But now Trudy impersonates Bob and sends the message. 29 00:02:00,440 --> 00:02:06,500 Here is let's meet today at six p.m. Alissa gets confused and again, replace Bob. 30 00:02:06,800 --> 00:02:09,520 I already told you, OK, I will come. 31 00:02:10,040 --> 00:02:11,510 But this creates confusion. 32 00:02:12,080 --> 00:02:14,440 Rather, this is a very simple case of replanning. 33 00:02:14,960 --> 00:02:19,900 Now, for the same example, let us consider the scenario of bank here. 34 00:02:20,210 --> 00:02:25,200 Bob and Trudy are good friends and Alice is an employee working in a bank. 35 00:02:26,180 --> 00:02:32,540 Bob asks Alice here, Alice, please send ten thousand dollar to Judy on my behalf. 36 00:02:33,380 --> 00:02:35,270 Alice sends the money to Trudy. 37 00:02:36,510 --> 00:02:43,890 Judy is mischievous and again replays the same message like, hey, Alice, please send Trudy ten thousand 38 00:02:43,890 --> 00:02:47,880 dollars or else things like is the message from Bob again. 39 00:02:48,270 --> 00:02:53,490 And Alice says, Bob, I've only sent and again sends the money to Trudy. 40 00:02:54,060 --> 00:02:55,620 This is a replay attack. 41 00:02:56,910 --> 00:02:59,290 Next is the denial of service attack. 42 00:02:59,910 --> 00:03:02,790 It prevents normal use of communication facilities. 43 00:03:03,390 --> 00:03:10,200 This attack may have a specific target, for example, and indeed all messages directed to a particular 44 00:03:10,200 --> 00:03:10,920 destination. 45 00:03:11,610 --> 00:03:18,090 Another form of service denial is the descriptions of an entire network with a very disabling the network 46 00:03:18,300 --> 00:03:21,840 or overloading it by messages which degrade performance. 47 00:03:23,010 --> 00:03:27,700 Let us consider the scenario of Alice and truly here to this intercept. 48 00:03:28,950 --> 00:03:30,580 Bob is sending mixed signals. 49 00:03:30,840 --> 00:03:31,560 Hello Alice. 50 00:03:31,680 --> 00:03:32,420 How are you? 51 00:03:32,820 --> 00:03:35,940 There truly is blocking the messages sent by Alice. 52 00:03:37,730 --> 00:03:40,220 That send a message like, I'm fine, Bob, what's up? 53 00:03:40,400 --> 00:03:45,710 But Bob is not receiving this message while I incents Alice, are you? 54 00:03:46,670 --> 00:03:49,230 Therefore, this is an example of denial of service attack. 55 00:03:49,550 --> 00:03:56,030 This can be very handy in case of browsers like if you're trying to access some website, but the website 56 00:03:56,030 --> 00:04:00,020 is not replying to and you're just sitting idle waiting for the reply from Lipsett. 57 00:04:00,590 --> 00:04:03,770 The website may have undergone the denial of service attack. 58 00:04:06,300 --> 00:04:10,290 Now, we have discussed all types of passive and active attacks. 59 00:04:10,860 --> 00:04:17,490 Let's go through the motives and goals in the attack, like to cause business loss information, to 60 00:04:17,490 --> 00:04:25,440 create fear, to demean someone demanding ransom revenge, illegal access to organization, leaked confidential 61 00:04:25,440 --> 00:04:27,900 information and promoting political beliefs. 62 00:04:30,680 --> 00:04:33,630 Let us have a quick recap of what we learned in this lecture. 63 00:04:34,130 --> 00:04:41,000 We learn different types of attacks like masquerade modification, replay denial of service. 64 00:04:41,570 --> 00:04:45,920 In the next lecture, we will learn about the world's top security organizations.