Counterterrorism Advisory Board Act of 2017 This bill amends the Homeland Security Act of 2002 to establish in the Department of Homeland Security (DHS), for a four-year period, a Counterterrorism Advisory Board, which shall: (1) be composed of senior representatives of DHS operational components and headquarters elements, and (2) coordinate DHS intelligence activities and policy and information related to DHS's counterterrorism mission and functions. The board's charter shall: (1) direct it to focus on the current threat environment and the importance of aligning DHS counterterrorism activities under the Secretary's guidance, and (2) be reviewed and updated every four years. The DHS Under Secretary for Intelligence and Analysis shall serve as the chair of the board and shall report to the congressional homeland security committees on the board's status and activities.