CIOs at financial institutions have a lot to think about every day. But one of the biggest areas of risk takes place when data is copied from one system to another. A single simple activity (such as depositing a check or making a mortgage payment) can require 10 or more separate systems. By the end of a transaction, there could be more than a dozen copies of the same data. Stopping the practice of copying data can be accomplished in a few weeks at less than 1% of the cost.”]
Source: https://www.darkreading.com/attacks-breaches/banking-on-data-security-in-a-time-of-insecurity