When a situation is not risky, there is little need to manage or measure the risk involved.  This applies equally to lending money to friends, reading utility meters, and until a few years ago, handling credit card transactions.  With the growing risk to financial transactions there is a need to improve the ways acquiring banks, processors, gateways, and even merchants manage and measure their risk.

In fact, prior to the PCI DSS the metrics involved in measuring the risk in an acquiring bank’s merchant portfolio were rather basic.  You look at the number of transactions per month and categorize the merchants into business categories.  One would say that online gambling would be riskier than grocery stores.  The logic seemed flawless, at least for the environment at the time.

Unfortunately the environment changed and hackers turned from fame and glory seekers to those wanting large financial payoffs from their prowess.  They began attacking merchants and even banks by finding the low-hanging-fruit never imagined by the industry.  The hackers began targeting:

  • POS systems directly connected to the Internet with weak remote access methods
  • Weak or insecure wireless located at physical stores
  • Insecurities in partner and vendor connections to companies
  • Insecure web application software

The hackers identified, by brute force, holes in the security of an industry that were never imagined by those creating the metric for managing their risk.  When the compromises reached a tipping point, the industry began to shift the focus to security.  The banks and card brands formed the PCI Security Standards Council (PCI SSC or Council) in 2006 and invited merchants, POS vendors, and other industry experts to participate (as Participating Organizations.)

In order to realize the importance of this change you have to first understand that people do things based on incentives, and for most companies security is not something they are very willing spend money on.  This can be seen in the ever increasing number of data breaches that occur every day.  Anyone who has had teenagers can tell you that in order to “encourage” a person to do the right thing you need to properly incent them.  Regulatory compliance has been the thing that has incented companies to place an importance on information security for the last 10 years, and PCI DSS compliance has been the leading force for the last three years.

This might pass over as just another regulatory issue like GLBA or SOX if not for the fact that it’s not specific to a business vertical.  The payments industry is sometimes called a “horizontal” because it cuts across so many areas such as banking an finance, travel and entertainment, health care, power and energy, etc.  In fact PCI DSS is the first globally enforced, industry regulated, cross-industry compliance program.  It’s goal is simple: prevent the electronic and paper theft of payment card data.

But why?  Don’t you like it when we ask why?  The reason was not to do this because it’s the right thing.  We all like to say we are acting “green” by composting when really it’s just a way of reducing the cost of our garbage bill.  We want to prevent the loss of this data because someone is paying for the fraud: other merchants, acquiring banks, and many more.

So, we begin to understand that acquiring banks use the binary aspect of PCI DSS compliance as a measuring stick to determine the risk within their merchant portfolio.  Sure there are still the number of transactions, type of business, and size of the organization, but now there is the check box of security.  What does this really mean in practical terms?

Well, of all the PCI DSS requirements, the most important by all accounts is 3.2 which mandates that sensitive authentication data should not be retained post-authorization.  The other requirements for security act to protect this data from being intercepted in the first place.  The end result is that hackers should never have any access to this sensitive authentication data.

OK, so the standard exists to protect the super secret data so banks can measure how risky their merchants are to them.  This acts much like the credit rating agencies such as Moody’s and Standard & Poors.  The question is, “Are the current  metrics sufficient for measuring risk in a merchant portfolio?”

I would argue that, much like the credit rating that says “AAA”, the PCI DSS is only one part of the holistic approach merchant banks should take to measuring risk within their portfolio.  Think back to the collateralized debt obligation (CDO) market that just exploded.  People were packaging mortgages together into one security that people could then trade against.  The problem is understanding the impact that all those thousands of mortgages and the people behind them will have on the value of that one security.

In a similar way, banks need to look at PCI DSS as just one factor in analyzing the risk to their portfolio.  I’d argue that to keep the model working one should look to the Verizon Data Breach report and analyze attack vectors to determine what areas should be measured.

If we look at the data breach landscape we see the following numbers:

  • 74% resulted from external sources
  • 20% were caused by insiders
  • 32% implicated business partners
  • 39% involved multiple parties

The metrics companies and banks should use for measuring risk should include:

  • Third Parties and the data they share (all three types)
  • Deployment of a wireless network (proximity to acceptance channels such as POS)
  • Number and size of business processes (POS network, databases, applications)
  • Connected business units (call center, data warehouse, or physically insecure locations)

Individual merchants need to prioritize attack vectors.  If we know that more hacking events occur due to weak passwords or default passwords we should focus on eliminating things like “<blank>” or “password” or “<vendor name>” rather than focusing on achieving 7 character, alpha-numeric ones (which for the record are no better than 5 character ones in theory.)

I argue that we need more focus on attack vector trending threat models for regulatory compliance before we focus on the broad spectrum of security best practices.