The Security Standards Council (SSC) of PCI reminded us today that a scope statement still requires validation. A scope should be reduced only after a thorough assessment of controls.

Secure treatment of data (e.g. hashing) could reduce the number of systems that are kept within scope but this needs to be assessed and verified. Another example is an entity that claims it has no wireless. This claim must be tested and they must have a regular process and control capability (wireless scanner) to manage risk going forward. Assessors will look for supporting documentation before they can allow scope to change. When scope is done properly it generates confidence on exactly where to look based on tests and evidence.

This is not to say that it is easy. A major retail executive once told me his company had no need for antivirus on their point of sale devices. Why? He believed his systems had no viruses, therefore he saw no need for antivirus. I had to convince him that he should be taking the opposite approach. Use of antivirus would confirm the lack of viruses. An absence of empirical data, let alone awareness of helpdesk and incident reports, did not register with this executive. This is a fine case of why risk is something that can not always be left to intuition alone or to market forces. Many actors operate with trust or hope rather than a complete or reasonable data set. A month after installing antivirus the executive was extremely thankful — he soon found a clear path to reduce point of sale outages and thus his operating costs were significantly reduced.

The steps to take after hearing “no” and “out of scope” are illustrated nicely in the SSC Wireless Guidelines decision tree:

The PCI SSC just released a document on how to detect and prevent skimming.

Skimming, as the word implies, is capturing data as it passes through a device. That means devices are usually modified so they will copy and record data to unauthorized storage or they will send it out over an unauthorized network connection.

The guide includes many images of skimming devices as well as an easy risk assessment form to help outline potential areas of vulnerability such as physical location, hours of operation, personnel and technology. In a nutshell the advice is the usual “watch for anything suspicious”. This means anything that accepts cards should have a known safe appearance (wires, stickers) as well as a clean/safe space around it. Staff should be trained such that any changes to the appearance or items introduced into the safe space should raise suspicion and be reported.

If you see Tetris running on Chip and PIN terminal, for example, you should not assume all is well with security.

Criminals will try anything to get access to the card data. Have you seen those charity boxes that often sit on a counter near a register? These have been known to be used to place hidden cameras next to a device to record PIN information. Here is another example from the guide: