Hackers tried to get absentee ballots in Miami-Dade primary MIAMI, March 19 (UPI) -- Computer hackers requested 2,500 absentee ballots for last year's Florida primary from the Miami-Dade Elections Department, officials say. The request is the first documented case of a cyberattack involving a U.S. election, NBC News reported. But experts say the goal of the attackers is unclear, especially because the number of ballots requested would not have made a difference in the outcome of the primary. The hackers could simply have been testing the system to see what they could do or to try to cause trouble with the voting rather than hoping to influence specific races, NBC said. Elections officials quickly realized the absentee ballot requests were phony. A state investigation was closed in January without any suspects being named, although a later report in The Miami Herald said the requests were later traced to three ISP addresses in the United States, although they had been routed through overseas servers. Experts say that computer attacks on elections remain a risk. "In this case the attack was not as sophisticated as it could have been, and it was easy for elections officials to spot and turn back," J. Alex Halderman, an expert on electronic voting security at the University of Michigan, told NBC. An attack somewhat more sophisticated than the one in Florida, completely within the norm for computer fraud these days, would likely be able to circumvent the checks.