WEBVTT 00:01.440 --> 00:07.440 Before we proceed further with actually writing Schenkel, let us try to understand the process that 00:07.440 --> 00:08.440 we are going to follow. 00:09.600 --> 00:12.780 We will write the functionality in a high level language. 00:12.780 --> 00:20.130 Like see, for instance, you want to write RiverCity official code before writing the actual shell 00:20.130 --> 00:21.150 code itself. 00:21.390 --> 00:24.840 It's a good idea to write the code in C language. 00:25.050 --> 00:32.760 And then we use estrus against the compiler C program because Astreus output will tell you what this 00:32.760 --> 00:38.550 calls are used in that C program so that we can use the same system in our assembly code. 00:39.420 --> 00:45.720 Once we identify the is being used to get the actual functionality that we want, we will have to know 00:45.720 --> 00:49.080 what arguments are needed for those Ciscos. 00:50.310 --> 00:56.190 In addition to the arguments to the discounts, we will also have to identify the fiscal numbers that 00:56.190 --> 00:58.200 are needed to invoke the fiscal. 00:59.240 --> 01:06.170 Every school will have a number using which we can invoke this school after all of this. 01:06.380 --> 01:12.560 We will ride our assembly code using the knowledge we have gained so far in the assembly code. 01:12.740 --> 01:20.270 We are going to use the schools and their associated arguments, and then they will also have to remember 01:20.270 --> 01:24.860 to avoid null bikes, null bikes usually break shall code. 01:25.220 --> 01:32.390 For instance, if you pass shall code with no right to steer S.P.I function, it will stop copying the 01:32.630 --> 01:36.180 code onto the stack as soon as an element is found. 01:36.980 --> 01:43.030 This is because Astar S.P.I thinks that it's the end of the string when are null by despond. 01:43.610 --> 01:45.500 Now we are avoiding null bytes. 01:45.500 --> 01:50.870 At a minimum, the vulnerable program may have more bad characters, but we are not going to deal with 01:50.870 --> 01:51.880 that at the moment. 01:52.340 --> 01:59.780 Let's only worry about null bytes and let's try to avoid them while writing our code and the last and 01:59.780 --> 02:06.980 final step, we will extract the usable cell code from the alpha binary that is produced from the assembly 02:06.980 --> 02:07.330 code. 02:08.060 --> 02:08.660 That's it. 02:08.720 --> 02:14.450 These are the seven steps that we will try to follow wherever we can while writing shall code in this 02:14.450 --> 02:14.900 module. 02:15.780 --> 02:23.460 Just to reiterate, we will write the C program, we will stress it, we will get the details of what 02:23.460 --> 02:29.760 this calls are used, and we will use the man pages of those calls to know the arguments. 02:29.910 --> 02:32.850 And then finally, we will write the assembly code. 02:33.900 --> 02:40.380 We will try to avoid nail bites and finally extract the shell code from the alpha binary, so that's 02:40.380 --> 02:41.100 the process. 02:41.340 --> 02:44.200 We are going to write Exit Chilcote in the next video. 02:44.580 --> 02:45.240 See you there.