A spate of distributed denial of service (DDoS) attacks have been providing cover for the theft of millions of dollars at three US banks, according to Gartner.
The method was used as cover for fraudulent wire transfers at the institutions.
Gartner Avivah Litan said DDoS attacks are being used much more frequently as criminals are finding it easy to divert the attention of bank security staff by using them.
In a blog post, Ms Litan explained the how the hackers implement the attack saying it involves the takeover of the payment switch via a privileged user account that has access to it.
By using this method the criminals "can simply control the master payment switch and move as much money from as many accounts as they can get away with until their actions are noticed."
He advised banks to implement a slow down to the money transfer system while under a DDoS attack.
By Claire Archer