A former FBI cyber investigator, speaking on condition of anonymity, said the breach is "really bad for our undercover agents" and described being in a group chat with current agents worried that their personal information could soon be freely available online to criminals and hostile nation-state hackers. Staff fear they could be targeted, or that criminals could use the data to create highly convincing phishing attempts, scams, or demands for bribes.
Some agents are also concerned about the risk of physical attacks from cyber criminals they have investigated. "One of the things we are discussing in the group chat is 'violence-as-a-service' attacks from young online gangs," the former worker told the BBC. "They could use this information to harass an FBI agent who has worked on their cases."
ShinyHunters, believed to be an English-speaking gang, has in the past been linked to swatting incidents and even petrol bomb attacks against law enforcement officers and rivals. The group claims it breached FBI systems on Monday and later posted details of the attack on its darknet site.
On Wednesday, the FBI acknowledged the breach, stating it was "aggressively investigating" how it occurred. The agency has not responded to further requests for comment.