Hacking an ATM with a Samsung Galaxy 4 Smartphone

Hackers hit ATM systems forcing them to dispense the cash stored in their money cases relying on certain commands sent through a smartphone.

Cybercriminals can hack ATM systems and force it to dispense the cash using a smartphone, in the specific case a Samsung Galaxy 4 phone.

The model of smartphone is not important, the mobile devices are used only to send commands to the ATM remotely once the attacker has physically connected it to the machine.

Poorly protected ATMs result more exposed to this type of attacker, hackers compromise their case in order to connect the mobile device.

Security expert Brian Krebs has published an interesting post titled “Thieves Jackpot ATMs With ‘Black Box’ Attack” to describe this kind of attacks belonging to “a new class of skimming scams aimed at draining ATM cash deposits”.

The “black box” ATM attack described by Brian Krebs relied on a smartphone and a USB-based circuit board.

“At issue is a form of ATM fraud known as a “black box” attack. In a black box assault, the crooks gain physical access to the top of the cash machine. From there, the attackers are able to disconnect the ATM’s cash dispenser from the “core” (the computer and brains of the device), and then connect their own computer that can be used to issue commands forcing the dispenser to spit out cash.” states Krebs.

Resuming, the criminal crews isolate the cash dispenser from the ATM PC and connected it a PC they control using the smartphone. Krebs reported that the “black box attacks,” have been conducted against ATMs made by the NCR vendor.

“NCR says the crooks then attached a smart phone (a virgin, out-of-the-box Samsung Galaxy 4), which they used as a conduit through which to send commands to the cash dispenser remotely. According to Harrow, the mobile phone was set up to relay commands through a dynamic IP service.” said Krebs.

In one case, the attacker used a circuit board with USB connection to hook it to the ATM controller in order to trick the computer into believing it was still connected to the cash dispenser. Krebs highlighted that anyway the supplementary circuit was unnecessary for the “black box” ATM attack.

“They plugged into the controller a USB-based circuit board that NCR believes was designed to fool the ATM’s core into thinking it was still connected to the cash dispenser.” states the post.

It’s not the first time that NCR ATMs have been targeted by hackers, in the past we discussed another attack technique that relies on a malware injected through a CD-ROM inserted the ATM core.

In October 2014, criminal gangs in Eastern Europe conducted several attacks against ATM machines, not only tampering them with card skimmers which steal debit card data, but also using malware.

The malicious code used by cyber criminals allows hackers to steal cash from the ATM without using cloned credit cards. The Interpol conducted a joint operation with experts at Kaspersky Lab, which allowed them to detect the Tyupkin malware on nearly 50 machines. As explained in a blog post on SecureList, Tyupkin submissions to Virus Total were mainly from Russia (20), but other samples (4) were reported also from the United States, India and China.

At the moment, researchers at NCR was informed only about two black box attacks, for this reason the company issued a firmware update to its machine that improve the encryption for the communication between the cash dispenser and the core system. The update also includes a feature that block the possibility to roll-back the version of the firmware, the downgrade could be exploited by hackers to make the ATM vulnerable again.

“The company also recently shipped a software update for its ATMs that strengthen the encryption used to manage communications between the cash dispenser and the ATM core. More importantly, the update changes the system so that the encryption key exchange between those two components is only done when the dispenser receives a specific authentication sequence.”

The experts at NCR confirmed that this kind of attack is very easy to organize and are very cheap.

“All things considered, this is a pretty cheap attack,” said Charlie Harrow, solutions manager for global security at NCR. “If you know the right commands to send, it’s relatively simple to do. That’s why better authentication needs to be there,”

Another modification included in the update refers to blocking the possibility to roll-back the version of the firmware so that the machine becomes vulnerable again.

[adrotate banner=”9″]

Pierluigi Paganini

(Security Affairs –  ATM, cybercrime)