Do you remember the days of sneakernet? That was a long time ago when people would move files between machines with a floppy disk as there was no network infrastructure. These days its quite simple to transfer a file over the network but for some reason, the use of USB flash drives seems to have brought new light to the term sneakernet. With how small they are and sometimes can fit nicely onto your keychain, USB flash drives have found their way back to being mainstream for moving files around. Part of this is due to the mobility of laptops. When in a desktop environment, files are usually moved on the network no problem but as people get together with laptops, it is much quicker to transfer files with a USB drive.
There are a couple big concerns with this process that needs to be addressed. To start, you never know what is on that drive. Most operating systems will have an automount and then an autoplay function to make it easy for you to open it up. While this is a nice feature, it also lets in potential dangers. An attacker may decide to have software setup on the flash drive that loads when inserted and then installs some sort of backdoor or phone home software. There is even campfire stories of hackers installing malicious software onto cheap USB drives and then purposely leaving them around the city for people to plug into their computers. So what is to prevent this, disabling autorun would be a good start. Making sure your anti-virus software is up-to-date would also be good with on-load scanning.
The above paragraph is really the background that I want to give for this part though. What about those files that YOU put on the drive. Say you work from home sometimes and your internet service provider connection is really slow, so you decide that you will put your work onto a USB drive and offload it onto your desktop in the office the next day. Sounds like a simple plan but what about that USB drive in transit? Wouldn’t it be quite easy for it to slip out of your bag or fall out of the door of your car? I could describe quite a few scenarios here but I hope you get the point. Someone is most likely going to pick up that USB drive and plug it into their computer. If that USB drive is not encrypted in some way, then you have opened up all your secret files to the public.
There are also a lot of cool ways to protect those files. The easiest way would be to simply add a password to the file if the software allows you to. This would still allow someone to see the files and possibly brute force their way into it. Another option is encryption software such as bitlocker or truecrypt. These can encrypt the entire USB drive so when someone plugs it in, the operating system just thinks it needs formatted as it cannot read the drive properly. One of my favorite ‘cool’ ways of USB drive protection is my fingerprint reading USB flash drive. When you first plug it in, the user is presented with a small accessible filesystem. It also mounts a fake cd drive with fingerprint reading portable software. After my fingerprint is authenticated, it unmounts the public filesystem and then mounts my private filesystem. Neat eh?
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