Researchers Eyal Itkin and Itay Cohen said in a detailed technical blog post that their research indicated the exploits — which they attributed to the Equation Group, a term coined by security outfit Kaspersky in 2015 as an alias for the NSA — had reached the hands of an alleged Chinese group which then repurposed them to attack American targets.

The first instance of this happening was reported by Symantec in May 2019, with its research showing that a group, which it named Buckeye, had been in possession of, and utilising, the NSA exploits in question.

Symantec said one possibility for the leak it found, was that Buckeye "may have engineered its own version of the tools from artefacts found in captured network traffic, possibly from observing an Equation Group attack".

Itkin and Cohen listed their main findings as under:

• "The caught-in-the-wild exploit of CVE-2017-0005, a 0-Day attributed by Microsoft to the Chinese APT31 (Zirconium), is in fact a replica of an Equation Group exploit code-named 'EpMe';
• "APT31 had access to EpMe’s files, both their 32-bit and 64-bit versions, more than two years before the Shadow Brokers' leak;
• "The exploit was replicated by the APT during 2014 to form 'Jian', and used since at least 2015, until finally caught and patched in March 2017;
• "The APT31 exploit was reported to Microsoft by Lockheed Martin’s Computer Incident Response Team, hinting at a possible attack against an American target;
• "The framework containing the EpMe exploit is dated to 2013, and contains four Windows Privilege Escalation exploits overall, two of which were 0-Days at the time of the framework’s development.
• "One of the 0-Days in the framework, code-named 'EpMo', was never publicly discussed, and was patched by Microsoft with no apparent CVE-ID in May 2017. This was seemingly in response to the Shadow Brokers leak."

Timeline of the events detailing the story of EpMe / Jian / CVE-2017-0005.

The Brokers announced they were in possession of hacking tools in 2016 and sought interested parties to negotiate a sale. When nobody engaged with them, they dumped the exploits on the Web in 2017.

One of these exploits, known as EternalBlue, was used to craft the Windows ransomware known as WannaCry which wreaked havoc in many countries in May the same year.

The identity of the Brokers has never been revealed, with the NSA telling iTWire as recently as September last year that it had no information to offer as to who was behind the group.