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Welcome back.

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Let's continue with the coding of our backdoor.

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Now before we even get into coding all of the different functions that we want our backdoor to have.

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Let us first write them down how we're going to do that.

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Well we're going to add a help option as a command that when the user of our server types help the backdoor

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we'll send all of its available features that it can do.

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Let me show you what they mean.

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If we go to our server program and to our target communication you remember here we compared the command

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with the quit.

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And in case the command was indeed quit then we break out of this loop and exit the program.

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Let's do the same with the help comment.

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So we're going to add an else if statement and we're going to compare the command with the help string

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in case the user of the server inputs help.

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Then we want to print in colored all of the different features and options that the door can execute.

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We're going to use three single open quotes and three single closed quotes and in between we're going

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to write all of the options that we want our backdoor to have.

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So let's start with the new line character.

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So everything gets printed out correctly.

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The first option is the quit command of course the command that we already coded as we can see right

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here.

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Quit.

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We're going to add we're going to tab it couple of times.

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Let's add a small arrow.

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And here it will tell.

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But this command does in our case it will quit session

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with the target.

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Simple as that.

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The next command can be the clear command and let's tab it all the way to here.

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And this command can clear the screen.

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So we're going to do the same thing as for example typing clear inside of our terminal.

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It gets rid of all of the previous commands that ran.

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And it gives you a clear and better look of your terminal.

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OK.

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So we're going to code that as well.

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The next command that we want to add would be DCD and then direct rename.

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So we want to change the directories.

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Let's specify between these star signs directory name indicating that it can be any name you want.

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Let's set these two arrows and type what this command does.

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It changes the rectory on target system.

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Let's not forget to add the upload and download functions to our back door.

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So upload and then file name between these two star signs groups.

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We did not want to open this.

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So let's say what this does.

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We need to add this arrow and type upload file to the target machine.

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That's slower days so we can see this better.

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The next thing is to download the file for download file name

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and let's type right here download file from Target.

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Machine

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the next three commands will be something that we are going to steal from the Metropolitan.

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If you ever use an interpreter which you most likely did you know that there is an option to start the

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key logger to stop the key logger and to print all of the keystrokes that were inputted while the key

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logger was running.

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So let's steal those three options.

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And by steal I mean we are going to code them ourselves but we are going to base off of the maternity

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key logger so key log underscore start

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we'll start the key logger so start the key logger right here key log underscore dump

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print keystrokes that the target input it and keep log underscore stop

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stop and let's set a fun option stop and self-destruct.

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Key logger file.

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That sounds interesting and you will see how we're going to code that later on.

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As you remember I said that the key logger that we created was not its final form.

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So we're going to upgrade it and use it inside of our backdoor.

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And there is one last option that we want to add which is persistence.

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We want to add the program

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and the file name and now we need to tap all of this a little bit further so everything can fit.

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Okay so let's add the last description of our command create persistence in registry which simply means

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the tower program or our backdoor will automatically get started once the target restarts their machine.

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So they do not have to double click on our program and execute it multiple times.

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They can only do it first time and then we can run the persistence and then the program will hide itself

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inside of their machine and it will automatically start every time they restart their machine.

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Okay.

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So these are all the functions that we want to code inside of our backdoor for now and we only added

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the help option which will print what will be available to do with our backdoor.

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So let's see whether this will work.

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But before we actually test this to see whether this health option works we need to go to our backdoor

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and add it here as well.

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We need to type the line else if command equals equals to help.

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We simply just want to pass because we're not executing anything.

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We cannot leave it to do this as we can freely let the help comment execute because we are not.

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As we don't care about any output of the health command since it will get printed out by our server

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therefore we're simply just going to pass in case the backdoor receives the help command and then it

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will return to the beginning of the while True loop and it will try to receive the second command.

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So let's see whether all of this works of course here we need to add the term color dot colored and

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now all should be good for some reason this is still red underlined.

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So let's see what's wrong with this.

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Well let's just run it and see what the error is because I cannot really seem to find it at the moment

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so let's just run it by country server that be why.

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And it says invalid syntax in this line.

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Else if comment oh yeah we're missing one equal so else if equals equals to help.

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And now let's run the program.

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Everything should work fine now listening for the incoming connections and if we run the back door let's

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first of all test the regular commands that we can run as such.

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Who am I.

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And it seems to Hank.

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Let's check out the back door.

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Command is not defined.

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And if we go to our backdoor command is indeed not defined because we did misspell once again.

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So now it should work.

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Finally let's give it one less try Python 3 server the UI.

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Now let's go right here with Python 3 back door where my command works.

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Alice works nets that bash and R for example what would give us an output so everything works.

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What happens once we specify help

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been a sage help not found that that is because we still let it go through these lines of code and we're

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going to fix this in just a second.

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We get everything else printed out so let's go with the quick command and quick command works as well.

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Now let's fix this.

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And in order to fix this we need to add this to the else statement.

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So in any other case we're going to try to execute this if it is not quit and if it is not help we will

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executed.

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Let's test it once again just so we can make sure that this time it will not try to execute the help

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command.

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Let's run the backdoor run to help command and everything seems to work correctly but this time we get

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another letter which doesn't really allow us to continue executing the commands.

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You can see it simply just hangs after it prints this.

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Well let's see why we get that error so it should be a problem with our server I believe and that is

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also the same problem that we had before is as soon as it prints this it will go to the line where we

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try to receive the result.

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But remember in our back door we are not really executing anything and we are not really sending anything

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because this is now in the else statement.

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Therefore this is also trying to receive and this is also trying to receive resulting in our two programs

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hanging.

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So we need to add an L statement right here.

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So else tab this in tab this in as well.

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And let's give it one less try start our server then go to this terminal navigate to the back door project

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start our backdoor if I type held command we get the output of the help command everything gets printed

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out and we also get to execute the next command if we want.

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Let's try to quit command and everything works correctly.

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We do not get any error and all of these three options for now work.

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The only thing is we don't really print this in green and that is because we forgot to add right here

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green and now everything will work correctly.

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Okay so now that we added the help option the quit option.

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The next thing that we're going to do is we're going to add the clear option in the next video.

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So thank you for watching this tutorial and I will see you in the next lecture by.