The specialists from the Global Research and Analysis Team of Kaspersky Lab, of late undertook a forensic study into cyber-criminal attacks which took into account ATMs across the globe.

The experts found out in their investigation that a piece of malware infects these machines which enable the hackers to take away cash from the machines through direct transaction.

The company's expert further discovered that these attackers operate during the night-time on Sundays and Mondays only.

The attackers function by entering the ATM and inserting a bootable CD for setting up the malware, Tyupkin named by Kaspersky Lab. They gain full control over the machine post rebooting the system after the installation.

They operate by keying in an arrangement of digits on the ATM's keyboard instead of inserting the card into the card slot. After this, they call the operator to get further directions, and key in another combination of digits.

The correct entry of the numbers lets the attackers in on how much cash is held by the ATM in each cash cassette, which gives the hacker the option to empty which cassette, with the result that the machine begins to give out cash in big numbers, forty notes in one go from the selected cassette, post which the hackers run off.

The malware Tyupkin has till now been identified in ATM machines in Europe, Asia and Latin America.