WEBVTT - This file was automatically generated by VIMEO 1 00:00:08.700 --> 00:00:11.100 Hello everyone. Welcome back. Let's take a 2 00:00:11.100 --> 00:00:14.000 look at the next set of protocols to 3 00:00:14.500 --> 00:00:17.500 postpone that we'll be taking a look at is the element. So 4 00:00:17.500 --> 00:00:20.700 this protocol is used to connect games in your Contours 5 00:00:20.800 --> 00:00:24.200 on the remote server. So this provides bi-directional 6 00:00:23.200 --> 00:00:26.500 interactive session. So typically 7 00:00:26.500 --> 00:00:29.600 tell it can also be useful to login, code alert server using 8 00:00:29.800 --> 00:00:30.800 the user credentials. 9 00:00:31.900 --> 00:00:34.500 So one of the reasons is protocol wide 10 00:00:34.500 --> 00:00:37.500 like this because it is easily deployed and 11 00:00:37.500 --> 00:00:40.100 available on all major operating systems. So, 12 00:00:40.100 --> 00:00:43.500 in such a way, a ready-made tool kit is available in 13 00:00:43.500 --> 00:00:46.200 order to connect to any open ports for 14 00:00:46.200 --> 00:00:49.200 the major drawback of this protocol is that data is sent in 15 00:00:49.200 --> 00:00:52.400 plain text. So this creates an attack Vector for 16 00:00:52.400 --> 00:00:56.300 any attacker to sniff the data that is being transmitted. This 17 00:00:56.300 --> 00:00:58.400 take a simple example of how government works. 18 00:01:03.200 --> 00:01:07.100 I have a Windows command prompt open as a victim and 19 00:01:06.100 --> 00:01:09.500 we'll be trying to connect on to Linux 20 00:01:09.500 --> 00:01:12.500 system running telnet server for 21 00:01:12.500 --> 00:01:15.100 that. I'll just go ahead and start the sniffing. 22 00:01:26.400 --> 00:01:29.600 Now, in order to start the talent connection go 23 00:01:29.600 --> 00:01:31.000 to type in the command tent. 24 00:01:32.800 --> 00:01:36.100 Followed by port number and 25 00:01:35.400 --> 00:01:37.900 type address of the server. 26 00:01:42.500 --> 00:01:46.100 As you see, I am prompted to login session. 27 00:01:50.200 --> 00:01:52.400 Once I log in, I can perform the basic. 28 00:01:53.500 --> 00:01:56.900 Comments at the root cancer type in. So 29 00:01:56.900 --> 00:01:58.900 let's go ahead and snip the traffic. 30 00:02:04.900 --> 00:02:07.300 so, when I sort of typed in PC 31 00:02:07.300 --> 00:02:07.800 that 32 00:02:09.500 --> 00:02:12.100 We have a connection established between the client and the 33 00:02:12.100 --> 00:02:15.100 server that was intercepted and just going to 34 00:02:15.100 --> 00:02:17.900 go ahead and follow this extreme. 35 00:02:19.600 --> 00:02:22.200 So as we can see, we have all 36 00:02:22.200 --> 00:02:25.200 the data in plain text. That is being transmitted. So 37 00:02:25.200 --> 00:02:28.200 in this particular example, I have intentionally put in a weak 38 00:02:28.200 --> 00:02:31.800 password. So the username being rude and password 39 00:02:31.800 --> 00:02:34.300 being a Schwinn which was any plain text. So this sort 40 00:02:34.300 --> 00:02:37.400 of with limitations on the protocol Itself by 41 00:02:37.400 --> 00:02:40.500 the ties, being Penn Central, Plain text 42 00:02:40.900 --> 00:02:43.400 for a Coke cans. New releases information. 43 00:02:44.600 --> 00:02:48.000 Now, let's take a look at the next protocol known as DNS. So 44 00:02:47.300 --> 00:02:50.700 DNS o stands for domain name, so, 45 00:02:52.200 --> 00:02:55.700 So, typically, this protocol is used to map diaper dressed 46 00:02:55.800 --> 00:02:58.200 and the domain host leaves. So 47 00:02:58.200 --> 00:03:01.700 typically as an end user, we cannot remember all 48 00:03:01.700 --> 00:03:04.700 the IP addresses on which different applications run 49 00:03:04.700 --> 00:03:07.200 on. So, rather than that, we 50 00:03:07.200 --> 00:03:10.700 use human readable form such as domain names such as w 51 00:03:10.700 --> 00:03:13.400 dot facebook.com, which can be easily remembered by us 52 00:03:13.700 --> 00:03:16.800 and we can use that in order to access the server. But 53 00:03:16.800 --> 00:03:19.100 ideally, this server is going to resolve the 54 00:03:19.100 --> 00:03:21.600 domain name with IP address. Such that the 55 00:03:21.800 --> 00:03:22.800 To can be established. 56 00:03:24.300 --> 00:03:27.700 So, technically this particular informations are 57 00:03:27.800 --> 00:03:30.600 stored in the hosts file that is available on 58 00:03:30.600 --> 00:03:34.000 different organ systems, which will have the basic mapping 59 00:03:33.400 --> 00:03:36.800 in case. The DNS information 60 00:03:36.100 --> 00:03:39.100 is not available in the 61 00:03:39.100 --> 00:03:42.300 host file. Then we have for DNS servers that are configured on 62 00:03:42.300 --> 00:03:45.400 a router. So with again lead to the mapping. 63 00:03:47.200 --> 00:03:50.400 So technically one of the drawback is that these DNS queries do 64 00:03:50.400 --> 00:03:53.700 not actually track from where information is being requested. 65 00:03:53.900 --> 00:03:56.200 One last protocol that I like 66 00:03:56.200 --> 00:04:00.000 to talk about is as IP address, but this is the 67 00:03:59.400 --> 00:04:02.300 actual IP address that we sort of 68 00:04:02.300 --> 00:04:05.200 use in order to access remote machines, all the 69 00:04:05.200 --> 00:04:08.100 local machine. So that means a 70 00:04:08.100 --> 00:04:11.600 three device. Over the network, has to have an IP address, 71 00:04:11.100 --> 00:04:14.800 either in the local network, or over the internet in 72 00:04:14.800 --> 00:04:17.600 order to establish connection without this. None 73 00:04:17.600 --> 00:04:19.500 of the networking would be possible as of correct. 74 00:04:20.300 --> 00:04:24.700 So one of the drawback of this protocol would be that it can be spoofed. So 75 00:04:24.700 --> 00:04:27.200 technically an attacker can actually, masquerade is 76 00:04:27.200 --> 00:04:31.000 own IP address behaving as another known victim 77 00:04:30.200 --> 00:04:33.300 within the same infrastructure and carry any 78 00:04:33.300 --> 00:04:34.400 specific payload. 79 00:04:35.900 --> 00:04:37.600 That's it for this video. Thank you.