The FBI is warning banks about a global fraud scheme called an ATM cash-out.
The attacks will see the cyber criminals target a bank or payment card processor, using cloned cards at cash machines across the world to fraudulently withdraw millions of dollars in a matter of hours.
It is believed that the attacks are linked with a major security breach at a card issuer, with the attackers using malware to access custoemr card information and obtain network access.
That's according to Krebs on Security, who says FBI intelligence indicates that cyber criminals across the world are preparing to carry out the highly choreographed cash-out imminently.
Historic compromises have included small-to-medium size financial institutions
"The FBI has obtained unspecified reporting indicating cyber criminals are planning to conduct a global Automated Teller Machine (ATM) cash-out scheme in the coming days, likely associated with an unknown card issuer breach and commonly referred to as an ‘unlimited operation'," reads a confidential alert sent out by the FBI, shared privately with US banks last Friday.
It continues: "Historic compromises have included small-to-medium size financial institutions, likely due to less robust implementation of cyber security controls, budgets, or third-party vendor vulnerabilities," the alert says. "The FBI expects the ubiquity of this activity to continue or possibly increase in the near future."
Just before executing ATM cashouts, the organised cyber crime gangs will remove many of the fraud controls of the banks using phishing techniques, such as removing the maximum ATM withdrawal amount, or any limits on the number of customer transactions per day, maximising how much they can steal.
The FBI expects the ubiquity of this activity to continue or possibly increase in the near future
The crooks could also have the capability to alter account balances and security measures to make an unlimited amount of money available at the time of the transactions.
"The cyber criminals typically create fraudulent copies of legitimate cards by sending stolen card data to co-conspirators who imprint the data on reusable magnetic strip cards, such as gift cards purchased at retail stores," the FBI warned. "At a pre-determined time, the co-conspirators withdraw account funds from ATMs using these cards."
Almost all of the ATM cashout operations launched so far have been done so on weekends, Krebs said, often just after financial institutions begin closing for business on Saturday.
In preparation for the forthcoming attacks, the FBI is now urging banks to review how they handle security, such as implementing two-factor authentication using a physical or digital token when possible for local administrators and business critical roles, said Krebs.
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