Cyber crime is gaining more and more momentum as a source of threats for final users. Credit card, banking and financial frauds are continuously reported in the news and often studied in the literature: recent studies have uncovered a whole infrastructure of services that are available to cyber criminals to deploy their attacks. Cyber crime activities are supported by infrastructures and services originating from an underground economy. Exploitation tools, automated redirection of user connections to arbitrary domains, and trading of new malware or vulnerabilities are only examples. These infrastructures and services must be sustained and provided by an underlying economy.