North Korea's computer operating system revealed by researchers

North Korea has been developing its own operating system for more than a decade. Photograph: Reuters

North Korea's homegrown computer operating system mirrors its political one – marked by a high degree of paranoia and invasive snooping on users, according to two German researchers.

Their investigation, the deepest yet into the country's Red Star OS, illustrates the challenges Pyongyang faces in trying to embrace the benefits of computing and the internet while keeping a tight grip on ideas and culture.

The operating system is not just the pale copy of western ones that many have assumed, said Florian Grunow and Niklaus Schiess of the German IT security company ERNW, who downloaded the software from a website outside North Korea ^[1] and explored the code in detail.

"[The late leader] Kim Jong-il said North Korea should develop a system of their own. This is what they've done," Gunrow told the Chaos Communication congress in Hamburg on Sunday.

North Korea, whose rudimentary intranet system does not connect to the world wide web, but allows access to state media and some officially approved sites, has been developing its own operating system for more than a decade.

This latest version, written around 2013, is based on a version of Linux called Fedora and has eschewed the previous version's Windows XP feel for Apple's OSX – perhaps a nod to the country's leader Kim Jong-un who, like his father, has been photographed near Macs.

But under the bonnet there's a lot that is unique, including its own version of encrypting files. "This is a full blown operation system where they control most of the code," Grunow said.

The researchers say this suggests North Korea wants to avoid any code that might be compromised by intelligence agencies.

"Maybe this is a bit fear-driven," Grunow said. "They may want to be independent of other operating systems because they fear back doors," which might allow others to spy on them.

Grunow and Schiess said they had no way of knowing how many computers were running the software.

Private computer use is on the rise in North Korea, but visitors to the country say most machines still use Windows XP, now nearly 15 years old.

The Red Star operating system makes it very hard for anyone to tamper with it. If a user makes any changes to core functions, like trying to disable its antivirus checker or firewall, the computer will display an error message or reboot itself.

Red Star also addresses a more pressing concern - cracking down on the growing underground exchange of foreign movies, music and writing.

Illegal media is usually passed person-to-person in North Korea using USB sticks and microSD cards, making it hard for the government to track where they come from.

Red Star tackles this by tagging, or watermarking, every document or media file on a computer or on any USB stick connected to it. That means that all files can be traced.

"It's definitely privacy invading. It's not transparent to the user," Grunow said. "It's done stealthily and touches files you haven't even opened."

Nat Kretchun, an authority on the spread of foreign media in North Korea, said such efforts reflected Pyongyang's realisation that it needs "new ways to update their surveillance and security procedures to respond to new types of technology and new sources of information".

There is no sign in the operating system of the kinds of cyber-attack capability North Korea has been accused of, the researchers say.

"It really looks like they've just tried to build an operating system for them, and give the user a basic set of applications," Grunow said. That includes a Korean word processor, a calendar and an app for composing and transcribing music.

North Korea is not the only country to try to develop a bespoke operating system. Cuba has National Nova, and China, Russia and others have also tried to build their own.