How to FUD your trojan/server with a HEX editing & File splitting method

Our FUDDING tool requirements and download links.

First of course an AV what I am going to be using is AVAST the free edition.

DOWNLOAD HERE

File splitter to split our servers to find out where the virus signature is to modify it.

DOWNLOAD HERE 

Best hex editor I have found and its free of charge.

DOWNLOAD HERE

Now lets begin.

Now go grab the server you want to edit mine is going to be a Spyrex keylogger server.

Before we begin turn AV off.

You result may vary on AV your using. 

Now place you server in a folder I recommend naming it A trust me on this. Now my server name is test.exe.

Okay now once you have placed the server in a file lets scan it.

And.......

OMG it got caught 

Ok now where to start open The File Splitter and Calc.exe to split the  file.

In
the file splitter browse to the server you want to split and choose
Custom size. Now it tells me that this server is exactly 53,495 bytes
and I want to split it into 4 pieces. So I go to Calc and divide it by 4
now place the number you got after dividing it and place it in the
splitter custom size box like I have at the bottom. Now click on Split.

Now you should get the files in the same directory like I have below.

Now scan each of them to figure out witch file we have to split again.


 Now once you have figured it out make a new folder named the part
number that was detected now I got part 3 so I'm gonna make a new folder
named 3 . 

Now I
hope you didn't close file splitter if so reopen it and browse to
test.exe.3 to split and change the output folder to 3 like I have in the
picture below. We are also going to split this file into 4 pieces again
so open up Calc and divide by 4.

I made a drawing on this if your confused 

Now you should have this inside folder named 3.

Now

scan each file again to figure out witch file we need to split but also
be aware of how small the file is getting. Once you figure out witch
file needs splitting make a new folder with the parts name. I got part
test.exe.3.3 so I am going to make a new folder and name it 3.

Now

once you made new folder named 3 open up file splitter and browse to
the file that got detected mine was test.exe.3.3 and pick the output
directory to the folder we just made witch was the folder named 3.

Now

browse to the new folder and scan the new files we split. As you can
see test.exe.3.3.4 was detected so I'm gonna make a new folder and name
it 4.

Now in file splitter pick the file that got detected witch was test.exe.3.3.4 and choose the new folder we made named 4.

 Now lets scan the new files and see witch got detected ocne we find it open it up with the HEX editor and see if its still to big to figure out what we need to change.

Ok so it's test.3.3.4.1 that we need to edit do open it up with your favorite hex editor or use the one I provided earlier. Once you open it it will look something like this.

Now

the virus signature is in here don't get scared its not that hard now
my method of figuring it is looking for something that stands out or
guesssing. All you really have to do is change a letter from capital to a
lower case one now what worked for me was changing D to a lower case
from the word DLLHOOKSTRUCT.

Now save it exit and scan it it should be undectable.

  

Congratz now its FUD now all you need to do it compile it and scan it one more time and run it to test.

Now compiling I will show you one example and you can figure out the rest by your own.

Now you see the splitter icon inside your folder click on it and it will recompile the file.

Now

once you made that file copy it and go back one directory and past it 

then it will ask you to replace it click yes and keep doing this till 

you go back to first directory. And your done.

Source:-http://enc0de.blogspot.com