Make USB drive write protected

I carry my USB flash drive that contains a lot of portable tools with me all the time but I am afraid of one thing, which is a computer virus such as JambanMu or MaxTrox that is able to infect USB flash drives and bind itself to the executable files in there. So far there are only ways to disable writing to USB flash drive on your computer by editing the registry but if you plug it into a public computer which has virus, your USB flash drive will be writable and can be infected by virus. So is having a pendrive with a built-in write protect switch the only way to prevent the drive from virus infection?

Few days ago I found out about PenProtector which claims to protect all removable disks from additions of new files. PenProtector prevents the writing on pendrive of viruses, trojans, dialers and any other type of executable that would use the removable disk to replicate it self. PenProtector cost €3,90 and I bought a copy to see what it really does. From my observation, PenProtector creates a “block” file to fill up the remaining free space on the USB flash drive. When there is no space left on the removable drive, virus won’t be able to copy itself to to drive or infect any executable files.

PenProtector

Honestly, it is not worth buying PenProtector because there are a few FREE ways to write protect a USB flash drive by creating a fake dummy file to fill up the removable disks free space.

First, you have to know how much free space is left on the USB drive. Plug in the drive, go to My Computer, right click on the drive letter and select Properties. Take note of the “Free space” that is in bytes. My USB drive has 1,300,594,688 free space, so I will need to create a dummy file that has the exact file size.

Removable Drive Free Space
The best and easiest way is to use fsutil, a command line tool included in Windows. Open up command prompt from Start Menu > Accessories and type the following command:

    fsutil file createnew F:\IamDummy 1300594688

fsutil file createnew

You will see that your USB flash drive’s LED is blinking meaning the file is being created. Now my pen drive has 0 free space and virus won’t be able to get in. You can change 1300594688 to the size that you want in bytes. F: is the letter of my USB flash drive and IamDummy is the file name. When you want to copy files into the USB removable drive, simply delete the dummy file. When you’re done, create the dummy file again using the fsutil command.

Write Protect USB Removable Drive

If you’re looking for a graphical tool to create dummy fake files, here are a few that I found. Some are slower, and some with NTFS restriction, so you might want to test it out to see which you prefer to use.

1. NOD32 Dummy File Creator

NOD32 Dummy File Creator
NOD32 Dummy File Creator Utility is meant to create dummy files in a specified folder to immunize a system against particular worms. Same concept as DiskHeal which creates autorun.inf file so the virus won’t have the chance to overwrite it. Supports setting file attributes (hidden, system, archive, read-only) to the dummy file on both NTFS and FAT drives.

2. DonationCoder’s Dummy File Creator (DFC)

Dummy File Creator
This tool is able to create dummy files of any arbitrary size filled with a specify hex byte value.

3. Nikko Dummy File Creator

Nikko Dummy File Creator
A simple program which creates files of any size with ease. This program also has a built-in random function, so users can choose to create either compressible or non-compressible files. Can create multiple fake files from batch list file.

Here is another example why you’d want to use these fake dummy file creators. To earn 1 point in RapidShare, we will need to upload a 5MB file for people to download. Let’s say you have a 3MB file and short of 2MB. Instead of searching for it on your hard drive or on the Internet, you can just create one yourself. You can also fool your friends by messing up their hard drive space, test drive transfer speed by moving dummy files, prevent data recovery by filling the free spaces and etc… I’m sure there are more.