The case involved more than 2,500 “phantom requests” for absentee ballots, apparently sent to the Miami-Dade County elections website using a computer program, according to a grand jury report on problems in the Aug. 14 primary election. It is not clear whether the bogus requests were an attempt to influence a specific race, test the system or simply interfere with the voting. Because of the enormous number of requests – and the fact that most were sent from a small number of computer IP addresses in Ireland, England, India and other overseas locations – software used by the county flagged them and elections workers rejected them.

Computer experts say the case exposes the danger of putting states’ voting systems online – whether that’s allowing voters to register or actually vote.

“It’s the first documented attack I know of on an online U.S. election-related system that’s not (involving) a mock election,” said David Jefferson, a computer scientist at Lawrence Livermore National Laboratory who is on the board of directors of the Verified Voting Foundation and the California Voter Foundation.