A line of ATMs stands inside a Perekrestok supermarket in Moscow. A report to be delivered Monday says that a hacking ring has stolen up to $1 billion total from more than 100 banks worldwide. (Andrey Rudakov/Bloomberg)

A hacking ring has stolen up to $1 billion from banks around the world in one of the biggest banking breaches known, a cybersecurity firm said in a report scheduled to be delivered Monday.

The hackers have been active since at least the end of 2013 and infiltrated more than 100 banks in 30 countries, according to Russian security company Kaspersky Lab.

After gaining access to banks’ computers through phishing schemes and other methods, they lurk for months to learn the banks’ systems, taking screen shots and even video of employees using their computers, the company said.

Once the hackers become familiar with the banks’ operations, they use that knowledge to steal money without raising suspicions, programming ATMs to dispense money at specific times or setting up fake accounts and transferring money into them, Kaspersky said. The report is set to be presented Monday at a security conference in Cancun, Mexico. It was first reported by the New York Times.

The hackers seem to limit their theft to about $10 million before moving on to another bank, part of the reason why the fraud was not detected earlier, Kaspersky principal security researcher Vicente Diaz said in a telephone interview with the Associated Press.

The attacks are unusual because they target the banks rather than customers and their account information, Diaz said.

The goal seems to be financial gain rather than espionage, he said.

“In this case they are not interested in information. They’re only interested in the money,” he said. “They’re flexible and quite aggressive and use any tool they find useful for doing whatever they want to do.”

Most of the targets have been in Russia, the United States, Germany, China and Ukraine, although the attackers may be expanding throughout Asia, the Middle East, Africa and Europe, Kaspersky said. In one case, a bank lost $7.3 million through ATM fraud. In another case, a financial institution lost $10 million by the attackers exploiting its online banking platform.

Kaspersky did not identify the banks and is still working with law enforcement agencies to investigate the attacks, which the company says are ongoing.

Associated Press