NARA describes itself as "the nation's record keeper."
NARA personnel discovered that the drive was missing on March 24 and reported the incident to senior NARA officials in April 2 after a search for the drive failed. It subsequently notified US-CERT, the White House Counsel's Office, staff of NARA's House and Senate oversight committees, and a representative of former President Clinton.
The agency is preparing to issue a breach notification to individuals who may be affected.
In a statement, NARA said that it "takes very seriously the loss of an external hard drive that contained copies of electronic storage tapes from the Executive Office of the President of the Clinton Administration." The agency said that it has reviewed its internal information controls and improved its security processes.
The agency's inspector general is conducting an investigation to determine who should be notified and whether additional action is warranted. NARA is offering a $50,000 reward for information that leads to the return of the hard drive.
The drive holds an unknown amount of personal information about White House staff and visitors, including names and Social Security numbers. It contains snapshots of the hard drives of departing administration officials, information that had been stored on 113 4-mm tape cartridges.
The original tapes and a backup hard drive remains in NARA's possession.
A NARA spokesperson did not immediately respond with information about individuals believed to be affected.
Attend a Webcast on protecting your company and customer data. It happens May 20. Find out more and register.