As with the first one, the responsibility for this one that started in December was claimed by a group of hackers that goes under the name of "Izz ad-Din al-Qassam Cyber Fighters", and is allegedly a way to revenge themselves on the U.S. for the release of a movie trailer in which the Muslim prophet Muhammad was mocked and ridiculed.
But, as unnamed U.S. government officials claimed for the NYT on Tuesday, the real instigator of the attacks is Iran.
Without offering any proof, they say that the scope, the sophistication and the targets of the attacks all point to a state-sponsored effort, and that they consider this to be retaliation for the economic sanctions the U.S. has imposed on the country and the cyber attacks they directed against Iran's nuclear facilities.
The Iranian government has, of course, denied being involved.
In the meantime, researchers at various security firms have been investigating the attacks and have come to the conclusion that the attackers used data centers and clouds, and even their own private clouds around the world to send out encrypted requests to the banks' sites.
According to Incapsula, they also hired a number of botnets to increase the pressure on the targeted sites.
"As we continued to monitor the incoming DoS commands we saw that the attacks were precisely timed, limited for periods that varied from 7 minutes to an hour. The botnet C&C was commanding it to work in 'shifts”', maximizing its efficiency and ordering it to renew the attack just as the target would start to recover, explained Incapsula's Ronen Atias.
"During some of these 'shifts' the backdoor was instructed to change target and attack unrelated commercial and e-commerce sites. This all led us to believe that we were monitoring the activities of a botnet for hire."