And it's only a partial fix at that. Last week, a couple of hackers released the code for malware that exploits a serious security flaw found in every single USB device, in hopes someone will come up with a fix. They've now released a partial solution themselves, and it involves coating your USB stick in epoxy.

In case you haven't been following the whole saga, Wired first reported a couple months ago that all USB devices have a fundamental security flaw in which the firmware, controls the device's basic functions, can be altered in ways that are virtually undetectable.

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The security researchers who found the flaw, Karsten Nohl and Jakob Lell, also wrote a piece of malware called BadUSB that exploits it. With BadUSB installed on a USB drive, a hacker can stick it into a USB port and "completely take over a PC, invisibly alter files installed from the memory stick, or even redirect the user's internet traffic." Last week, two other security researchers, Adam Caudill and Brandon Wilson, also reversed-engineered the flaw and posted the malware code on Github.

Caudill and Wilson now have now also released an incomplete fix. Their patch code, posted on Github, disables "boot mode," a mode that allows firmware to be reprogrammed. But this patch only works the latest version of USB code, so devices with older versions are out of luck.

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And then there's the epoxy. The firmware on a USB can still be reprogrammed with "pin shorting" as long as hackers have physical access to the device. Wired explains it this way:

That method involves plugging the drive into a computer while placing a piece of conductive metal across two or three of the pins that connect the controller chip to the USB stick's circuit board ...That finicky method acts as a sort of "hard reset" that allows the firmware to be reprogrammed.

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So if you coat the insides of a USB drive with epoxy, Caudill and Wilson, suggest, then it can't be opened up for pin shorting.

Ultimately, these "fixes" are only stop-gap measures. The real heart of the problem is that firmware can be altered without any visible traces, which a security researcher tells Wired is technically possible to fix. Until then, it's probably easier to be very, very wary of your USB devices—especially ones from strangers—than to subject them to a sticky craft project. [Wired]

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