Last year's massive hack of the US Office of Personnel Management's security clearance system affected 21.5 million people, including 1.8 million people who didn't apply for a background investigation, officials said Thursday, making it official the breach was the worst in US government history.
The new figure includes most, if not all, of the 4.2 million people the agency previously said were exposed in a separate breach of personnel files. The much larger number resulted from the hack in June or July of last year on the system used to conduct background checks on contractors and other private sector employees, as well as federal workers. Some 1.1 million of the stolen records included applicants' fingerprints. Background checks for people applying with the Central Intelligence Agency weren't affected because that agency conducts its own security clearance investigations.
"If you underwent a background investigation through OPM in 2000 or afterwards (which occurs through the submission of forms SF-86, SF-85, or SF-85P for either a new investigation or a reinvestigation), it is highly likely that you are impacted by the incident involving background investigations," OPM officials warned in an update published Thursday. "If you underwent a background investigation prior to 2000, you still may be impacted, but it is less likely."