When you think of North Korea, the first thing that springs to mind is probably not a well-featured tablet PC. But that's just what researchers at the Chaos Communication Congress hacking festival revealed on Tuesday.
Called Woolim, this tablet is designed to limit the distribution of contraband media, track its users, and generally act as a propaganda platform for the Democratic People's Republic of Korea (DPRK).
“It's pretty locked down,” researcher Florian Grunow told in an interview on Tuesday. Grunow presented the research along with co-researchers Niklaus Schiess and Manuel Lubetzki. Woolim is a small, white Android device that looks like a fairly standard tablet. The hardware itself is made by Chinese manufacturer Hoozo, but the North Korean government has removed some components such as those for Wi-Fi and Bluetooth, and put its own bespoke software on top.
After the researchers presented work covering RedStar OS, North Korea’s Linux-based operating system, a South Korean NGO offered the tablet to the group. Woolim is just one of several tablets designed for North Korea, but Woolim appears to be the most recent, likely dating from 2015.
The tablet has PDFs on how to use it; various propaganda texts for users to read as well as the capability to play local TV and connect to the country’s own internet, and it also comes with a slew of educational apps, such as French, Russian, and Chinese dictionaries. There's even an app for kids which teaches them how to type with a keyboard, and video games such as Angry Birds that have been lightly customized.
But don't try to push Woolim much further than that: it won't let you. The tablet only allows specific files to be used or played: users cannot just load whatever they want onto the device. “This goes for all of the files; it even goes for HTML files and for text files,” Grunow said. When a user tries to open a file, the tablet will check the file's cryptographic signature; unless it was a file generated by the tablet itself—such as a photograph the user took—or a file sanctioned by the government, it simply won't open. Grunow demonstrated this by trying to open a third-party .APK file on the device, with no success.
“For a normal user in DPRK I would say it's nearly impossible to get around the signature algorithm,” Grunow said. Woolim also constantly keeps tabs on what its users are up to. Whenever a user opens an app, the tablet takes a screenshot. These screenshots are then available for viewing in another app, but they can’t be deleted.
“This is the clear message: we see what you're doing right here,” Grunow said. It's not totally clear who in North Korea would have access to this sort of tablet, however. Grunow said that the hardware itself would cost around 160-200 Euros from the Chinese manufacturer, so presumably it might be a bit more expensive in North Korea itself. “The target audience is definitely someone with money, so it's not the normal working class I would suppose,” he added.