The group is responsible for the release of the National Security Agency's (NSA) hacking exploits which highlighted a Windows vulnerability used by hackers in the recent WannaCry global ransomware attack. This includes a cohort of zero-day vulnerabilities in some of the well-known web browsers, network routers, phone handsets and Microsoft's latest operating system - Windows 10.
In a blog post written in its trademark broken English, the group said it has more so-called Ops Disks, which it says were also stolen from the NSA. However, given the group's track record of leaking legitimate information that many believe to be sourced from the NSA, it is likely that at some point, this data will become public, one way or another. But either way, it's a noteworthy statement from the group - alternately berating tech countries and tech companies for not buying its data, and directly attacking Microsoft.
Shadow Brokers' new claim that it possesses information on the nuclear programmes of state governments is extremely worrisome, said Mr Joseph Lorenzo Hall, chief technologist for Washington think-tank Centre for Democracy and Technology.
He has been in custody since his arrest and is facing espionage charges.
As a quick refresher, a hacking group known as the Shadow Brokers released a treasure trove of NSA exploits and hacking tools just a few weeks ago. NSA whistleblower Edward Snowden and others confirmed the leak was authentic.
Trying to capitalize on the success of the WannaCry ransomware, which used ETERNALBLUE for a self-spreading SMB worm, The Shadow Brokers are now announcing the "TheShadowBrokers Data Dump of the Month" service, a monthly subscription plan.More news: Melee erupts at Tennessee high school graduation - in church
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In December, Shadow Brokers cancelled its auction and offered to sell the exploits.
The ransomware Attack was because of the existing Windows XP systems throughout the world which had been announced unsupported by Microsoft after 2014.
National security journalist Marcy Wheeler has suggested that Shadow Brokers' recent claims of a new Windows 10 exploit might be a deliberate attempt to inflame tensions between Microsoft and the U.S. government.
A spokeswoman for Microsoft said it was now once again preparing a response.
Two months before the WannaCrypt exploit hit the wild Microsoft released a patch, suggesting some cooperation between NSA and the software company. The US government has not commented directly on the matter. "Unwitting HUMINT [Human Intelligence]", the group claimed in its blog. "Witting HUMINT. Russian, China, Iran, Israel intelligence all doing same at global tech companies".
The hacker group came to public attention past year when it attempted to auction off a set of older cyber-spying tools, which it said was stolen from the US National Security Agency.