DHS Interagency Counterterrorism Task Force Act of 2017 (Sec. 2) This bill amends the Homeland Security Act of 2002 to authorize the Department of Homeland Security (DHS) to assign DHS personnel to participate in overseas interagency counterterrorism task forces to: (1) facilitate the sharing of counterterrorism information; and (2) combat the threat of terrorism and associated risks to the United States stemming from overseas sources of conflict or terrorism, as determined by DHS. (Sec. 3) DHS shall report, by 18 months after this bill's enactment and annually thereafter for 3 years, on activities carried out pursuant to this bill.