Kaspersky Lab cyber security company reported that overall, hackers stole up to $1bn from banks all over the world in one of the largest banking breaches, which lasted since at least the end of 2013 and infiltrated over a hundred banks in 30 countries.

Security experts explained that after obtaining access to banks’ computers via phishing schemes and other methods, cyber criminals could lurk for a few months to get acquainted with the banks’ systems. They took screenshots and even made video of employees while those were using their computers.

After the intruders became familiar with the operations of the financial institutions, they used that knowledge to steal funds without raising suspicions: they programmed ATMs to dispense cash at specific times or set up fake accounts and transferred money into them.

According to Kaspersky Lab, the hackers were stealing no more than $10 million and then targeted another bank. This is why fraud was not detected earlier. Besides, the attacks were quite unusual, since they targeted banks as financial institutions rather than their clients or their account data. In other words, hackers are looking for financial gain. Security experts describe them as flexible, aggressive and using any tool to achieve their goal.

The list of targets includes banks from the US, Germany, Russia, China and Ukraine. However, the chances are that the attackers have already expanded throughout Asia, the Middle East, Africa and Europe. Kaspersky specialists revealed that in one case, a bank lost $7.3 million from ATM fraud,another bank lost $10m after the attackers managed to exploit its online banking platform. In the meantime, the report of the security company did not reveal the list of targeted banks, as Kaspersky Lab continues to cooperate with law enforcement agencies to investigate the attacks that are still ongoing.

According to the Financial Services Information Sharing and Analysis Center, a non-commercial agency that alerts banks about hacking activity, it received a briefing about the report of Kaspersky Lab in January. Although the agency couldn’t comment on individual actions its members have taken, it still issued an official statement to say that the banks are trying to prevent and detect such kinds of attacks and minimize their impact. In addition, the agency pointed out that the news that Russian banks were the primary victims of the hackers might be a significant change in targeting strategy by Russian-speaking cyber criminals.

The United States is currently very alert to the cyber security issues, following numerous data breaches of mass retailers (like Target and Home Depot) and a member of the entertainment industry (Sony Pictures) and even a health insurer (Anthem). Now the administration calls to replace the existing state laws with a national standard that would give companies one month to notify their clients if their personal data has been compromised during the cyber attack.