1984: GUNMAN Project found typewriter implants in U.S. Embassy in Moscow.
For a detailed accounting of this story, visit the link below to read the NSA CCH publication written by NSA historian Sharon A. Maneki, called “Learning from the Enemy: The GUNMAN Project.” This historical monograph details how the Soviets for eight years were able to steal American secrets from inside the U.S. embassy in Moscow and the U.S. consulate in Leningrad (now St. Petersburg).
...beginning in 1976, the KGB successfully installed sophisticated miniaturized electronic eavesdropping equipment and burst transmitters inside 16 IBM Selectric typewriters used by the staffs of the Moscow embassy and Leningrad consulate, which copied everything being typed on the machines, then periodically broadcast their take to KGB engineers manning listening posts just outside.
The KGB bugs were discovered eight years later in 1984 by a NSA operation codenamed Project GUNMAN, which was the brainchild of the NSA deputy director for communications security, Walter J. Deeley. Shortly after President Ronald Reagan approved the project in February 1984, NSA secretly sent a team of electronic eavesdropping and communications security specialists to Moscow to look for the Soviet bugs.
Over the span of just 100 days, the NSA team replaced every piece of communications and encryption equipment, teletype machines, computers, printers, copiers, and typewriters then being used at the U.S. embassy in Moscow and the consulate in Leningrad, and replaced them with new “clean” equipment covertly brought in from the U.S. The old equipment was shipped back to NSA headquarters at Fort George G. Maryland, where every item was visually inspected an x-rayed by NSA specialists.
The first bugged IBM Selectric typewriter was discovered during a routine x-ray inspection at Ft. Meade on July 23/24, 1984. By the time the operation was completed, NSA technicians had found bugs inside 16 IBM Selectric typewriters, all of which had been shipped to Moscow and Leningrad between October 1976 and January 1984.
In the end, NSA concluded that the Soviets eavesdropping operation had most likely compromised every document typed on these 16 electric typewriters over the span of eight years from 1976 to 1984.