When we think of insider cybersecurity threats to a business or government agency, we conjure images of spies working on behalf of a foreign government. But many insider threats are accidental, explains Bob Anderson, a principal in the Chertoff Group's global Strategic Advisory Services. Anderson, who has been involved in investigating and arresting some of the most famous spies in U.S. history during his career with the FBI, breaks down the different categories of corporate threat — from the busy employee who inadvertently clicks on malware to those with more insidious aims. He offers insights on what makes a good insider threat program, why gaining employee trust is so difficult, and why corporate boards need to proactively examine their IT infrastructure and cybersecurity practices and procedures.