The FBI is probing a computer-security breach targeting Citigroup that resulted in the theft of tens of millions of dollars by hackers who seem to be linked to a Russian cyber gang, according to government officials.
The attack took aim at Citigroup's Citibank subsidiary, which includes its North American retail bank and other businesses, the Wall Street Journal reported. It couldn't be learned whether the thieves gained access to Citibank's systems directly or through third parties, the paper said.
The FBI and the National Security Agency, along with the Department of Homeland Security and Citigroup, swapped information to counter the attack, according to a person familiar with the case. Press offices of the federal agencies declined to comment.
The cyber attack on Citibank was believed to have taken place last summer but U.S. investigators suspect the attack could have taken place a year earlier, the paper said.