The FBI alerts urged banks to notify customers if they notice any wire transfers destined for Raohe, Fuyuan, Jixi City, Xunke, Tongjiang or Dongning.
Avivah Litan, an analyst at Gartner, said banks need to do more to protect themselves from such attacks, especially since they are in a better position to tackle the problem.
"These attacks are using the same techniques that have been used for a couple of years against business bank accounts and more recently against enterprise systems and security companies," Litan said. "The attacks keep coming, because most banks have yet to build up sufficient defenses.
There has been speculation that the Federal Financial Institutions Examination Council (FFIEC), a standards-setting body for the financial services industry, could soon require banks to implement stronger forms of user authentication, but no action has been taken.
A Gartner survey conducted in February found that many banks continue to rely on "crude" security measures, such as cookies and secret questions, to protect online accounts, Litan said.
"Nearly two-thirds of the surveyed banks manage their fraud detection and customer authentication projects by committee, which means [security is] always someone else's responsibility. It should come as no surprise, then, that the attacks are succeeding."
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