1 00:00:00,450 --> 00:00:03,670 How do we communicate with our website? 2 00:00:04,320 --> 00:00:10,200 Most of you probably know this already, but I will mention it in this video just so we can get a quick 3 00:00:10,200 --> 00:00:10,890 refresher. 4 00:00:11,460 --> 00:00:17,310 We explained all of these attacks in the previous video, but it's important we know the basics behind 5 00:00:17,310 --> 00:00:20,430 communication between a client and a website. 6 00:00:21,400 --> 00:00:29,770 So we send requests and receive pages back with the help of HTTP requests and HTP responses. 7 00:00:30,800 --> 00:00:37,490 HTTP request is something that we send to the website once we want to get a certain Web page from that 8 00:00:37,490 --> 00:00:44,720 website and HTP response is a response from the website telling us that either it found the page that 9 00:00:44,720 --> 00:00:47,030 we were looking for or it didn't. 10 00:00:47,780 --> 00:00:53,390 HTP response also contains an HTML code of the Web page that we requested. 11 00:00:53,930 --> 00:01:00,860 Now this would be a basic explanation of the process, but let us also take a look at how an HTP request 12 00:01:00,860 --> 00:01:03,530 and an HTP response look like. 13 00:01:04,040 --> 00:01:12,250 So if we take a look at this image right here in the red letters, we can see HTP request to some Web 14 00:01:12,260 --> 00:01:17,360 page while in deep blue letters we see and HTTP response. 15 00:01:18,330 --> 00:01:25,860 Let us focus first on HTTP request, so some of the known fields from the request would be fonts you 16 00:01:25,860 --> 00:01:33,000 see in the image we got hosts and that field defines the website domain that you are searching for. 17 00:01:33,870 --> 00:01:39,810 Sometimes this field can also have a port number due to Web servers, sometimes hosting more than one 18 00:01:39,810 --> 00:01:40,320 website. 19 00:01:41,040 --> 00:01:47,250 Besides that, we also got the user agent field and this field is used by server to identify the client 20 00:01:47,460 --> 00:01:49,650 that is connecting to the server. 21 00:01:50,340 --> 00:01:56,490 By identifying I mean, it would usually identify the Web browser that the client is using. 22 00:01:57,590 --> 00:02:04,130 HTP request can also have cookies, which we can see here in this picture, but what cookies are our 23 00:02:04,130 --> 00:02:10,450 values exchange between a client and the server that are used for holding data and information about 24 00:02:10,460 --> 00:02:12,470 a certain session that the user has? 25 00:02:13,570 --> 00:02:20,890 Sometimes and HTP request can also have authorisation parameter, which is used to check for the identity 26 00:02:21,460 --> 00:02:25,440 with this parameter, usernames and passwords are sent to the website. 27 00:02:25,960 --> 00:02:31,700 On the other hand, we got and HTP response, which also has some special fields of its own. 28 00:02:32,380 --> 00:02:35,290 First thing we see is the status code. 29 00:02:36,170 --> 00:02:42,860 Now, a field called status quo doesn't exist, but the value will be stored in the first line of the 30 00:02:42,860 --> 00:02:47,370 response most of you encountered at some point and fall for error. 31 00:02:47,510 --> 00:02:53,270 Once you try to search for a certain Web page and fall for in this case is a status code. 32 00:02:53,990 --> 00:03:00,410 In this picture we can see a status code of two hundred, which indicates that the page exists and therefore 33 00:03:00,410 --> 00:03:01,860 loaded it successfully. 34 00:03:02,570 --> 00:03:10,190 Besides this, we got set cookie field and this field, if defined, will establish values of cookies 35 00:03:10,400 --> 00:03:11,180 to the client. 36 00:03:12,040 --> 00:03:17,610 This value server can use later to identify the client and to also store clients data. 37 00:03:18,600 --> 00:03:24,930 We also got field called cash control, and this field is used if the content of the response should 38 00:03:24,930 --> 00:03:28,380 get stored inside the browser of the client or not. 39 00:03:29,300 --> 00:03:35,090 And we also got content that will tell us the size of the response in Bite's. 40 00:03:36,310 --> 00:03:43,510 Below all of these fields, we can see HTML tags opening and down there is the Web page that we requested 41 00:03:43,510 --> 00:03:44,660 from this website. 42 00:03:45,340 --> 00:03:51,640 It sends us the Web page code that will then get rendered inside of our browser and it will show us 43 00:03:51,640 --> 00:03:52,270 the Web page. 44 00:03:52,720 --> 00:03:54,110 Simple as that. 45 00:03:54,850 --> 00:03:55,240 Great. 46 00:03:55,450 --> 00:03:57,840 Now, that will refresh our memory about this. 47 00:03:58,240 --> 00:04:00,730 Let us finally start attacking websites. 48 00:04:01,300 --> 00:04:02,230 See you in the next video.