A group of cyber criminals is using a piece of malware to steal millions in cash from ATMs around the world — without having to use a credit or debit card. Security firm Kaspersky Lab discovered the hack, which is enabled by entering a series of digits on the keypad, and currently affecting ATMs from a major manufacturer running Microsoft Windows 32-bit.
So far, Interpol has alerted countries in Europe, Latin America and Asia, and is now carrying out a widespread investigation into the recent string of hacks. While no details relating to the group behind the attacks, Kaspersky Lab has reason to believe that they have already stolen millions of dollars using the Backdoor.MSIL.Tyupkin malware.
“Over the last few years, we have observed a major upswing in ATM attacks using skimming devices and malicious software,” said Vicente Diaz, Kaspersky Lab Principal Security Researcher. “Now we are seeing the natural evolution of this threat with cybercriminals moving up the chain and targeting financial institutions directly. This is done by infecting ATMs themselves or launching direct Advanced Persistent Threat (APT)-style attacks against banks. The Tyupkin malware is an example of the attackers taking advantage of weaknesses in the ATM infrastructure.”
According to the researchers, the fact that many ATMs run on operating systems with known security vulnerabilities and the absence of security solutions is another problem that needs to be addressed immediately.
“Offenders are constantly identifying new ways to evolve their methodologies to commit crimes, and it is essential that we keep law enforcement in our member countries involved and informed about current trends and modus operandi,” explained Sanjay Virmani, Interpol Digital Crime Centre Director.
How the Tyupkin attack works
- First, the criminals need to gain physical access to the ATMs, allowing them to insert a bootable CD that installs the malware.
- Once the system is rebooted, the ATM is under the control of the gang.
- The malware then runs in the background on an infinite loop awaiting a command.
- The malware will accept commands only at specific times, on Sunday and Monday nights, making it harder to detect.
- To activate the malware, a unique combination key based on random numbers is generated, to avoid the possibility of a member of the public accidentally entering a code.
- The criminal carrying out the theft on the ground then receives a phone call from another member of the gang, who relays a session key based on the number shown on the ATM’s screen. This helps prevent members of the gang going at it alone.
- When the session key is entered correctly, the ATM displays details of how much money is available in every cash cassette, allowing the attacker with physical access to select which cassette to steal from.
- After this, the ATM dispenses 40 banknotes at a time from the chosen cassette.
How to mitigate the attacks
The defense mechanism proposed here is extremely straightforward, and goes by the unimaginative yet highly descriptive name of “Secure Boot.” Though simple, given that it is hardware-based, it is incredibly strong.
“And, that is the lesson, Boldt adds. “One would think that financial institutions should know by now that they need to harden the targets with hardware, and not leave themselves and their customers exposed.”