Russian Hackers Blamed for Attack on JPMorgan

Russian hackers attacked the U.S. financial system in mid-August, infiltrating and stealing data from JPMorgan Chase & Co. and at least one other bank, an incident the FBI is investigating as a possible retaliation for government-sponsored sanctions, according to two people familiar with the probe. The attack resulted in the loss of gigabytes of sensitive data, said the people, who asked not to be identified because the probe is still preliminary.