The vulnerability of MasterCard Tokenisation Service (MDES) and Visa Tokenisation Service (VTS) lies in the absence of critical fields in the ARQC cryptographic algorithm (such as 9F15 MCC), which allows a malicious actor to disclose protected information.

The vulnerability of MasterCard Tokenisation Service MDES and Visa Tokenisation Service VTS lies in the possibility of arbitrary modification of the “Amount” field in the Authorisation Request ISO 8583 packet. Exploiting this vulnerability could allow a malicious actor to disclose protected...