Schedule

Schedule

Sunday, January 25

1422212400 The Tech Guy
1422226800 This Week in Tech

Monday, January 26

1422295200 Tech News Today
1422298800 Triangulation
1422304200 iPad Today
1422316800 Tech News 2Night

Tuesday, January 27

1422381600 Tech News Today
1422385200 MacBreak Weekly
1422392400 Security Now
1422399600 Before You Buy
1422403200 Tech News 2Night
1422406800 All About Android
1422415800 Padre's Corner

Wednesday, January 28

1422462600 FLOSS Weekly
1422468000 Tech News Today
1422471600 Windows Weekly
1422478800 This Week in Google
1422489600 Tech News 2Night
1422491400 Android App Arena
1422496800 Ham Nation

Thursday, January 29

1422554400 Tech News Today
1422558000 Know How...
1422561600 Marketing Mavericks
1422567000 Coding 101
1422570600 Home Theater Geeks
1422576000 Tech News 2Night
1422577800 The Giz Wiz

Friday, January 30

1422640800 Tech News Today
1422644400 This Week in Law
1422662400 Tech News 2Night

Saturday, January 31

1422730800 The Tech Guy

Sunday, February 1

1422817200 The Tech Guy
1422831600 This Week in Tech

Monday, February 2

1422900000 Tech News Today
1422903600 Triangulation
1422909000 iPad Today
1422921600 Tech News 2Night

Tuesday, February 3

1422986400 Tech News Today
1422990000 MacBreak Weekly
1422997200 Security Now
1423004400 Before You Buy
1423008000 Tech News 2Night
1423011600 All About Android
1423020600 Padre's Corner

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Bad USB, I Am Groot, and Defcon

August 14 2014

A USB hack that will make you drop your packets, Patrick Djelahanty shows how he built the "Baby Groot" out of common parts, see soundwaves, lock picking, and Defcon wrap up.

"Bad USB"
* German Researchers Karsten Knoll and Jacob Lell discovered an exploit in the way USB works
* ALL USB devices use some form of controller. They're small computers that interface the USB serial communications protocol with whatever device we want to connect via USB.
-- That controller is actually a small computer... and the computer runs an operating system that is determined by firmware.

What's the Exploit?
* The way that USB was created, that firmware is updateable. It's updateable because the creators of the USB standard wanted manufacturers to be able to reprogram the firmware if a flaw was ever discovered in that firmware.
* HOWEVER, that also means that a malicious user (hacker) could reprogram the firmware to make the device act in a way that the manufacturers had not intended.

What does that all mean?
* This means that a USB flash drive could be reprogramed to act like a keyboard
-- So after you plug it in, it issues a series of keystrokes that (for example) open Internet Explorer, navigate to a page that contains malware, then close the browser... all in a matter of seconds
* Or a USB flash drive could be reprogrammed to act like a network adapter
-- All the traffic you send and receive from your network would pass through this new network adapter, which would forward the packet stream to another computer before sending your trafic to the proper destinations.

Worse still... since your computer has USB devices INTEGRATED into the system (Keyboard, Mouse, Webcamera, Card Reader) a compromised USB device could be used to compromise the USB devices in your computer, which would then compromise any USB device that connects to your computer.

Ok... so why not just run an anti-virus? Or copy over new firmware? Or just make USB firmware non-programmable?

Let's take that one at a time: Anti-Virus
* Your system cannot see past the controller of a USB device.
-- The way USB devices work, the system can query the controller, and the controller will tell the system the status of the USB device.
-- If the controller is compromised, then you cannot trust it to report the correct status
** In other words, the only way an Anti-Virus would work would be if the malware infecting the USB device was programmed to tell the system that it was compromising the controller... an unlikely scenario.

Copying New Firmware:
* As with the Anti-Virus question, the system cannot see past the controller.
* When you update firmware on a USB device, the new firmware is loaded into memory, then the controller is responsible for overwriting its old firmware and reporting back to the system with the new firmware status.
* If I was writing BadUSB malware, the first thing I would to would be to disable that process: Allow the controller to copy the new firmware to memory, then strip off the revision number of the new firmware and report THAT to the system.
-- The system thinks it has new firmware, but the malware is still there.

Making USB devices unprogrammable:
* This is the most likely solution, but there are two MAJOR problems
1. It doesn't fix the BILLIONS of USB devices that are already in the wild.
2. If a manufacturer ever discovers a problem with their firmware (say, an exploit) there is no way to patch it.

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