Root access gained on Chromecast – and it’s not running Chrome OS after all

Chromecast setup

While Google’s new Chromecast dongle has only been out for a few days, in true fashion it has already been hacked, with a somewhat startling discovery made in the process. The folks at GTV Hacker are behind the exploit and explain it like this:

Our Chromecast exploit package will modify the system to spawn a root shell on port 23. This will allow researchers to better investigate the environment as well as give developers a chance to build and test software on their Chromecasts. … Lucky for us, Google was kind enough to GPL the bootloader source code for the device. So we can identify the exact flaw that allows us to boot the unsigned kernel. By holding down the single button, while powering the device, the Chromecast boots into USB boot mode. USB boot mode looks for a signed image at 0×1000 on the USB drive. When found, the image is passed to the internal crypto hardware to be verified, but after this process the return code is never checked! Therefore, we can execute any code at will.

Theoretically, Google could release a patch at any time to fix this exploit, but for the time being, it remains relatively easy to crack open. For most everyday users, this doesn’t really mean much yet – but the door is now wide open for developers to poke around and create awesome new apps that can take full advantage of all of Chromecast’s clever functionality.

Perhaps even more interesting, though, is the discovery that Chromecast isn’t really running a stripped down version of Chrome OS after all, even though that’s how it was described in the unveiling last week. Instead, GTV Hacker claims that  “it’s actually a modified Google TV release, but with all of the Bionic / Dalvik stripped out and replaced with a single binary for Chromecast.” Most of the code from Google TV was reused, and while you won’t be able to install any Android apps, the bootloader and kernel is all borrowed directly from Google TV. The folks at GTV Hacker say that they aren’t ruling out the possibility that this might one day become a Google TV stick, as well.

This news makes Chromecast all the more exciting, and I can’t wait for mine to arrive on Tuesday (if Amazon’s shipping estimate is correct). You can expect a full unboxing and hands on review shortly after.

[GTV Hacker via Engadget]
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John F

John was the editor-in-chief at Pocketables. His articles generally focus on all things Google, including Chrome and Android, although his love of new gadgets and technology doesn't stop there. His current arsenal includes the Nexus 6 by Motorola, the 2013 Nexus 7 by ASUS, the Nexus 9 by HTC, the LG G Watch, and the Chromebook Pixel, among others.

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