Security Experts:

Connect with us

Hi, what are you looking for?

SecurityWeekSecurityWeek

Fraud & Identity Theft

Flaws in ATM Dispenser Controllers Allowed Hackers to Steal Cash

ATM hacking exploits cash dispenser controller vulnerabilities

ATM hacking exploits cash dispenser controller vulnerabilities

Researchers have disclosed the details of two serious vulnerabilities affecting ATM currency dispensers made by NCR. The flaws have been patched, but they could have been exploited to install outdated firmware and get ATMs to dispense cash.

Positive Technologies experts Vladimir Kononovich and Alexey Stennikov have conducted a successful black box attack against the NCR S1 and S2 cash dispenser controllers. In these types of attacks, the attacker only sees inputs and outputs, without having any knowledge of the system’s internal workings.

The method, which the researchers described as a “logical attack,” requires physical access to the targeted device. In this particular case, an attacker could have leveraged the poor physical security of the targeted dispenser controller to connect to it, install vulnerable firmware, and issue commands that would instruct the machine to dispense cash.

The experts disclosed their findings this week at the Black Hat security conference in Las Vegas.

Two different security holes have been found that allow an attacker to roll back the firmware to an older, vulnerable version.

One of them is CVE-2017-17668, which affects the S1 controller, and the other is CVE-2018-5717, which affects the S2 controller.

The flaws are similar and they are both related to insufficient protection of the memory write mechanism. They can be exploited by an unauthenticated attacker to execute arbitrary code, bypass the firmware anti-rollback mechanism, and install firmware containing known vulnerabilities, according to Positive Technologies.

“Our research indicated that not all requests from the ATM computer to the dispenser were encrypted. Instead, encryption was applied only to requests deemed critical by the manufacturer, such as dispensing cash. But some of the so-called non-critical requests can be just as dangerous,” said Alexey Stennikov, Head of Hardware Security Analysis at Positive Technologies.

The researchers notified NCR of their findings and the vendor released critical firmware updates in February that should provide better protection against black box attacks. The update should address the firmware rollback vulnerability and it adds an extra layer of protection for physical authentication mechanisms.

“The physical authentication mechanism used to authorize encrypted communications to the dispenser has been strengthened to add protection against an attacker using endoscope technology in an attempt to manipulate dispenser electronics from outside the safe. Additionally, further authentication mechanisms have been added as configuration options,” NCR said in its advisory.

Related: New Strain of ATM Jackpotting Malware Discovered

Related: Massachusetts Man Pleads Guilty to ATM Hacking

Written By

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Click to comment

Expert Insights

Related Content

Identity & Access

Hackers rarely hack in anymore. They log in using stolen, weak, default, or otherwise compromised credentials. That’s why it’s so critical to break the...

Cloud Security

VMware vRealize Log Insight vulnerability allows an unauthenticated attacker to take full control of a target system.

Mobile & Wireless

Technical details published for an Arm Mali GPU flaw leading to arbitrary kernel code execution and root on Pixel 6.

Mobile & Wireless

Apple rolled out iOS 16.3 and macOS Ventura 13.2 to cover serious security vulnerabilities.

Mobile & Wireless

Apple’s iOS 12.5.7 update patches CVE-2022-42856, an actively exploited vulnerability, in old iPhones and iPads.

Vulnerabilities

Security researchers have observed an uptick in attacks targeting CVE-2021-35394, an RCE vulnerability in Realtek Jungle SDK.

Vulnerabilities

Google has awarded more than $25,000 to the researchers who reported the vulnerabilities patched with the release of the latest Chrome update.

Mobile & Wireless

Two vulnerabilities in Samsung’s Galaxy Store that could be exploited to install applications or execute JavaScript code by launching a web page.