The second line of defense is responsible for challenging the risk decision making of the first line of defense, which is the business process owners and managers. The second line of defense also provides oversight, guidance, and support to the first line of defense in implementing andmaintaining effective risk management practices. The second line of defense includes functions such as risk management, compliance, quality assurance, and internal audit. References = Risk and Information Systems Control Study Manual, Chapter 1: IT Risk Identification, Section 1.2: IT Risk Management Roles and Responsibilities, Page 14.