Two of the biggest ATM manufacturers, Diebold Nixdorf and NCR, have released software updates to address bugs that could have been exploited for “deposit forgery” attacks.
Deposit forgery attacks happen when fraudsters can tamper with an ATM’s software to modify the amount and value of currency being deposited on a payment card.
Such attacks are usually followed by quick cash withdrawals, either during weekends or via transactions at other banks, with the fraudsters trying to capitalize on the nonexistent funds before banks detect any errors in account balances.
Diebold Nixdorf ProCash 2100xe USB ATM does not adequately secure communications between CCDM and host. Diebold Nixdorf ProCash 2100xe USB ATMs running Wincor Probase version 1.1.30 do not encrypt, authenticate, or verify the integrity of messages between the CCDM and the host computer. An attacker with physical access to internal ATM components can intercept and modify messages, such as the amount and value of currency being deposited, and send modified messages to the host computer.
A bug in NCR SelfServ ATMs running APTRA XFS software has been patched. NCR SelfServ ATM BNA contains multiple vulnerabilities.
NCR SelfServ automated teller machines (ATMs) running APTRA XFS 04.02.01 and 05.01.00 do not encrypt, authenticate, or verify the integrity of messages between the BNA and the host computer. These are vulnerable to physical attacks on the communications bus between the host computer and the bunch note accepter (BNA). NCR ATM SelfServ devices running these versions contain vulnerabilities that can be exploited by an attacker with physical access to the internal components of the ATM, specifically the BNA and the host computer.
NCR SelfServ ATMs running APTRA XFS 04.02.01 and 05.01.00 implement 512-bit RSA certificates to validate BNA software updates. Keys of this strength can be broken by an attacker in a sufficiently short period of time, thereby enabling the attacker to sign arbitrary files and CAB archives used to update BNA software, as well as bypass application whitelisting, resulting in the ability to execute arbitrary code.
NCR SelfServ ATMs running APTRA XFS 05.01.00 do not properly validate softare updates for the BNA. An attacker with physical access to internal ATM components can restart the host computer. During boot, the update process looks for CAB archives on removable media and executes a specific file without first validating the signature of the CAB archive. This allows an attacker to execute abitrary code with SYSTEM privileges.