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# How to build a WinRAR Binder

Written by: CthulhuBunny & DIzzIE, with inspirational tunes by Macabre [c]opyleft 2003

## WinRAR Binder What?

The methods discussed herein will allow you to bind any file (or any number of files you want) to a WinRAR auto-executable file. The file will then be sent to a target user with the promise of a dummy payload. Along with the dummy payload, the desired secondary content (a rogue ftpd for instance) will also be installed in the background without the target user's knowledge.

Because WinRAR only allows you to specify one pre-designated install directory, what we will do is pack the dummy file (the file you said you are sending the user, a funny program for example) in its own autoexec, and then place the payload (a trojan for instance) and the dummy autoexec into another autoexec together. When the target runs this autoexec, both the payload and the dummy autoexec will be installed to the desired directory, however the autoexec will be directed to run on setup, thus the dummy file gets extracted to the directory specified in the dummy autoexec, and the target is told to look in that directory. Meanwhile the payload has been silently installed to the desired directory, for instance the startup folder, ready to run next time the target restarts her machine. Thus the target user will get his dummy file, while the payload gets safely dropped into place.

## WinRAR Binder How?

1) The first thing that is needed is a WinRAR client. Grab one at http://www.download.com or http://www.rarlab.com and a crack or serial at http://astalavista.box.sk

2) Open WinRAR and proceed to the location of the dummy file (dummy.txt for this example).

3) Click the Add button.

4) In Archiving Settings in the General Tab, select the "Create SFX Archive" checkbox.

5) Rename the archive name to whatever you want (dummy.exe in this example).

6) Select the Advanced Tab, and Click "SFX Options".

7) Under the General tab, "In Path To Extract" type the directory location you want the dummy file extracted to, C:\dummy\, or perhaps the Desktop (C:\Documents and Settings\All Users.WINDOWS\Desktop on Windows XP Pro)

8) The "Absolute Path" radio button should become selected by default when you do step 7, if not, make sure it is selected.

9) Under the Modes tab, in the Silent mode area, select the "Hide All" option.

10) Still under the Modes tab, in the Overwrite mode area, select the "Overwrite all files" button.

11) Click OK to exit out of the Advanced SFX Options menu.

12) Click OK to exit out of the RAR configuration menu.

13) You now have your dummy file in its own auto-executable RAR. Test it to make sure it works (just double click and check the specified install folder to make sure it unpacks there). Now it's time to make the main auto-executable that will contain both the dummy autoexec just made as well as the payload.

14) Move the payload file and the recently made dummy autoexec into the same directory (not necessary but saves the trouble of going through directories in the next step).

15) Open WinRAR again and proceed to the location of the payload file (malice.txt in this example) and the recently made auto-executable.

16) Select both dummy.exe and malice.txt (Click on one file, then hold down the Ctrl key and click on the other one, while holding down Ctrl to select both files).

17) Click the Add button.

18) In Archiving Settings in the General Tab, select the "Create SFX Archive" checkbox.

19) Rename the archive name to whatever you want (bindertest.exe in this example).

20) Select the Advanced Tab, and Click "SFX Options".

21) Under the General tab, In Path To Extract type the directory location you want the payload file extracted to (this is where the dummy autoexec will be extracted as well, but that is unimportant), C:\WINDOWS\system32 for example, or perhaps C:\Documents and Settings\All Users.WINDOWS\Start Menu\Programs\Startup (On Windows XP Pro) to make it start every time Windows starts. You will want to place the payload into the startup folder if you want the payload to run.

22) The "Absolute Path" radio button should become selected by default when you do step 22, if not, make sure it is selected.

23) In the setup program area still under the General Tab put in the name of the dummy auto-executable in "run after extraction" (dummy.exe).

24) Under the Modes tab, in the Silent mode area, select the "Hide All" option.

25) Still under the Modes tab, in the Overwrite mode area, select the "Overwrite all files" button.

26) If you want to get rid of the standard WinRAR auto-executable box icon, select the Text and icon tab and in the Customize SFX icon area, select another common icon. (optional)

27) Click OK to exit out of the Advanced SFX Options menu.

28) Click OK to exit out of the RAR configuration menu.

29) You now have your binded WinRAR auto-executable file. Use at will :)

To recap, what this will do when the target double clicks the exe is install both the payload and the dummy autoexecutable into the specified directory, will run the dummy autoexec file which will install the dummy file to a different directory. The payload file will be dumped into the startup directory, and will start next time the user reboots Windows (if you chose to place it in the startup folder). Tell the target what directory to find the dummy file in.

Drawbacks:
1) The target might notice the file size difference between the auto-executable you sent her, and the dummy file.
2) This might in turn lead the target to drag the auto-executable onto a WinRAR icon. This will open the autoexec in WinRAR and will allow him to see all of your dirty little SFX commands.

A proof of concept demonstration file is available here: http://dizzy.ws/bindertest.exe. This will install a dummy.txt (this text) into C:\dummy\ and a malice.txt into the startup folder (directory structures modeled on Windows XP Pro, you may need to modify the folder path for other operating systems).

Thus a sample scenario would g something like this: Here, I'm sending you ***** (dummy file name), it'll install into ***** (dummy file install path). The target runs the exe and gets his dummy file. Meanwhile the payload gets dumped into the startup directory, ready to start operation as soon as Windows is restarted.

Enjoy!

Get in touch: xcon0@yahoo.com

Copyright 2005, EuroHacker Magazine