Black Hat: How to make and deploy malicious USB keys

Spread them around public places and about half of them will get plugged into victim’s computers

USB keys were famously used as part of the Stuxnet attack on the Iranian nuclear program and for good reason: it’s got a high rate of effectiveness, according to a researcher at Black Hat 2016.

Of 297 keys spread around the University of Illinois Urbana Champaign 45% were not only plugged into victims’ computers but the victims then clicked on links in files that connected them to more malware, says Elie Burstzein, a Google researcher who presented the results.

+More on Network World: Black Hat: 9 free security tools for defense & attacking | Follow all the stories from Black Hat 2016 +

That rate was pretty constant regardless of where the keys were dropped and what they looked like, he says. Keys were left in parking lots, common rooms, hallways, lecture halls and on lawns. Some had no labels but others did that said confidential and exam answers. Some had metal door keys attached on a ring and some had door keys plus a tab with an address and phone number.

More than half of those that were opened were opened within the first 10 hours.

Twenty-one percent of those who plugged in the devices then took a survey to say why they did. Sixty-eight percent said they wanted to return the drives and 18% said they were just curious and the rest had various other reasons.

What were they curious about? Pictures were consistently popular at 33% to 45% depending on the type of key that was picked up. Resumes were about as popular as photos with a spike in interest to 53% for those keys that were unlabeled. Other documents not so much.

Burstzein says building the keys was not trivial. The team he worked with had to figure out how to make a device small enough to fit into a key case, create a mold for the case, pour the resin, figure out how to unmold it so it had a smooth look and trim it to appear professional. It took weeks to perfect the techniques. Each one cost about $40.

The team also spent a lot of time writing code for the keys that could figure out what operating system was running on the machine they were plugged into. One test was a shell script that tried to lock the scroll lock key. If it worked, it was a Windows machine.

It was difficult to test the timing between commands and know they were successfully executed so they used caps-lock toggling as an indicator. When a command was successful, it would toggle the switch as a feedback bit, he says.

The code used reverse shell to get thorough the firewalls, scripting language and obfuscation to avoid antivirus detection, used a payload that delivered a maximum 62.5 keystrokes per second and used metasploit to act as a command and control server.

Preventing USB key attacks isn’t easy. The best methods are to educate users not to plug them in, block their use altogether on machines or restricting use.

He’s posted a how-to on building the keys and the code to load on them.

Join the PC World newsletter!

Error: Please check your email address.

Tags black hat

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Tim Greene

Network World
Show Comments

Cool Tech

Crucial Ballistix Elite 32GB Kit (4 x 8GB) DDR4-3000 UDIMM

Learn more >

Gadgets & Things

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >

Family Friendly

Lexar® JumpDrive® S57 USB 3.0 flash drive 

Learn more >

Stocking Stuffer

Plox Star Wars Death Star Levitating Bluetooth Speaker

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

GGG Evaluation Team

Kathy Cassidy

STYLISTIC Q702

First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni

STYLISTIC Q572

For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell

LIFEBOOK UH574

The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi

STYLISTIC Q702

The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott

STYLISTIC Q702

My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?