D- Providers

Yes, home users are arguably the most vulnerable simply because they are usually not well protected. Adopting a 'path of least resistance' model, intruders will often zero-in on home users - often exploiting their 'always on' broadband connections and typical home use programs such as chat, Internet games and P2P files sharing applications. ControlScan’s scanning service allows home users and network administrators alike to identify and fix any security vulnerabilities on their desktop or laptop computers.
Any company that stores, processes, or transmits cardholder data on behalf of another entity is defined to be a Service Provider by the Payment Card Industry (PCI) guidelines.
Just check the list regularly updated sites:
  • MasterCard: Click on "Service Providers" then "Compliant Service Providers" then "Compliant Service Provider List"
  • Visa: Click on "List of Service Providers" in "Procedures and guidelines"
You can also ask the provider's Certificate of Compliance.
It is every provider who, for one reason or another, stores, processes or transmits cards data. Such providers can be : resellers, payment processing providers (PSP), hosts websites, call centers, cards manufacturer, etc..
Source : GIE-CB