Sunday, November 07, 2010
Anu
Most of you may be curious to know about how to make a Trojan or Virus on your own. Here is an answer for your curiosity. In this post I’ll show you how to make a Trojan on your own usingC programming language. This Trojan when executed will eat up the harddisk space on the root drive (The drive on which Windows is installed,usually C: Drive) of the computer on which it is run. Also this Trojanworks pretty quickly and is capable of eating up approximately 1 GB ofhard disk space for every minute it is run. So, I’ll call this as SpaceEater Trojan. Since this Trojan is written using a high levelprogramming language it is often undetected by antivirus. The Trojan isavailable for download along with the source code at the end of thispost. Let’s see how this Trojan works…
Before I move to explain the features of this Trojan you need to know what exactly is a Trojan horseand how it works. As most of us think a Trojan or a Trojan horse is nota virus. In simple words a Trojan horse is a program that appears toperform a desirable function but in fact performs undisclosed maliciousfunctions that allow unauthorized access to the host machine or createa damage to the computer.
Now lets move to the working of our Trojan
TheTrojan horse which I have made appears itself as an antivirus programthat scans the computer and removes the threats. But in reality it doesnothing but occupy the hard disk space on the root drive by justfilling it up with a huge junk file. The rate at which it fills up thehard disk space it too high. As a result the the disk gets filled up to100% with in minutes of running this Trojan. Once the disk space isfull, the Trojan reports that the scan is complete. The victim will notbe able to clean up the hard disk space using any cleanup program. Thisis because the Trojan intelligently creates a huge file in the WindowsSystem32 folder with the .dll extension. Since the junk file has the .dll extentionit is often ignored by disk cleanup softwares. So for the victim, thereis now way to recover the hard disk space unless reformatting his drive.
The algorithm of the Trojan is as follows
1. Search for the root drive
2. Navigate to WindowsSystem32 on the root drive
3. Create the file named “spceshot.dll”
4. Start dumping the junk data onto the above file and keep increasing it’s size until the drive is full
5. Once the drive is full, stop the process.
You can download the Trojan along with it’s source code HERE.
How to compile, test and remove the damage?
Compilation:You can use Borland C++ compiler (or equivalent) to compile the Trojan.
Testing:
To test the Trojan, just run the SpaceEater.exefile on your computer. It’ll generate a warning message at thebeginning. Once you accept it, the Trojan runs and eats up hard diskspace.
NOTE: To remove the warning message you’ve to edit the source code and then re-compile it.
How to remove the Damage and free up the space?
To remove the damage and free up the space, just type the following in the “run” dialog box.
%systemroot%system32Now search for the file “spceshot.dll“. Just delete it and you’re done. No need to re-format the hard disk.
Thanks
