DataSpii (pronounced data-spy) is a leak that directly compromised the private data of as many as 4 million Chrome and Firefox users via at least eight browser extensions. The eight browser extensions included Hover Zoom, SpeakIt!, SuperZoom, SaveFrom.net Helper, FairShare Unlock, PanelMeasurement, Branded Surveys, and Panel Community Surveys. The private data included personally identifiable information (PII), corporate information (CI), and government information (GI). DataSpii impacted the Pentagon, Zoom, Bank of America, Sony, Kaiser Permanente, Apple, Facebook, Microsoft, Amazon, Symantec, FireEye, Trend Micro, Boeing, SpaceX, and Palo Alto Networks. Highly sensitive information (e.g., private network topology) associated with these corporations and agencies was intercepted and sent t