34C3: Hacking the Nintendo Switch

There’s a natural order to the world of game console hacking: every time a manufacturer releases a new game console they work in security measures that prevent the end user from running anything but commercially released games, and in turn every hacker worth his or her salt tries to break through. The end goal, despite what the manufacturers may have you believe, is not to run “bootleg” games, but rather to enable what is colloquially referred to as “homebrew”. That is to say, enabling the novel concept of actually running software of your choice on the hardware you paid for.

At 34C3, noted console hackers [Plutoo], [Derrek], and [Naehrwert] have demonstrated unsigned code running on Nintendo’s latest and greatest (Note: the presentation is currently 404 Page Not Found on the CCC site, see embedded YouTube mirror below); and while they are keeping the actual exploit to themselves for now, they’ve promised that a platform for launching homebrew is coming shortly for those who are on firmware version 3.0.0. From the sound of it, after 9 months on the market, Switch owners will finally have complete access to the hardware they purchased.

The key to running the team’s own code was through a WebKit exploit that was already months old by the time the Switch was released. Loading up an arbitrary webpage was the tricky part, as the Switch generally uses its web browser for accessing official sources (like the online game store). But hidden away in the help menus of Tetris, the developers helpfully put a link to their website which the Switch will dutifully open if you select it. From there it’s just a matter of network redirection to get the Switch loading a webpage from your computer rather than the Internet.

It’s easier to ask for forgiveness than permission.

But as the more security-minded of our readers may have guessed already, that just gets you into the browser’s sandbox. The team now had to figure out a way to break out and get full control of the hardware. Through a series of clever hacks the team was able to learn more about the Switch’s internal layout and operating system, slowly working their way up the ladder.

A particularly interesting hack was used to get around a part of the Switch’s OS that is designed to check which services code is allowed to access. It turns out that if code doesn’t provide this function with its own process ID (PID), the system defaults to PID 0 because the variable is not initialized. In other words, if you don’t ask the operating system which functions you have access to, you will get access to them all. This is a classic programming mistake, and a developer at Nintendo HQ is likely getting a very stern talking to right about now.

But not everything was so easy. When trying to get access to the boot loader, the team sniffed the eMMC bus and timed the commands to determine when it was checking the encryption keys. They were then able to assemble a “glitcher” which fiddled with the CPU’s power using FPGA controlled MOFSETs during this critical time in an attempt to confuse the system.

The rabbit hole is pretty deep on this one, so we’d recommend you set aside an hour to watch the entire presentation to see the long road it took to go from a browser bug to running their first complete demo. It’s as much a testament to the skill of  [Plutoo], [Derrek], and [Naehrwert] as it is the lengths at which Nintendo went to keep people out.

We’ve seen other attempts at reverse engineering Nintendo’s hardware, but by the looks of it, the Switch has put up a much harder fight than previous console generations. Makes you wonder what tricks Nintendo will have up their sleeves for the next generation.