U.S. federal agencies refuse to testify about OPM hack

Officials from the U.S. government's personnel agency unexpectedly refused on Tuesday to attend a closed-door congressional briefing on their handling of a massive computer breach that affected more than 22 million federal workers. The breach last year at the Office of Personnel Management (OPM) underscored Washington's online vulnerabilities amid threats from perpetrators ranging from foreign governments to terrorist groups and various amorphous hacktivist collectives. OPM, the Department of Ho