Chinese hackers used a Windows-hacking tool created by the Equation Group, a security industry name for the highly sophisticated hackers widely understood to be a part of the NSA. The Chinese hackers then used that tool, which Check Point has named “Jian” or “double-edged sword,” from 2015 until March 2017, when Microsoft patched the vulnerability it attacked. Only in early 2017 did Lockheed Martin discover China’s use of the hacking technique, which Lockheed Martin has largely US customers, speculates that it may have been used against American entities.