Border Enforcement Security Task Force Reauthorization Act of 2017 (Sec. 2) This bill amends the Homeland Security Act of 2002 to require the Department of Homeland Security (DHS), before establishing a Border Enforcement Security Task Force (BEST) unit, to apply risk-based criteria that takes into consideration specified factors, including: whether the area in which the BEST unit would be established is significantly impacted by threats posed by transnational criminal organizations; the extent to which the unit would advance DHS's homeland and border security strategic priorities and related objectives; and whether departmental Joint Task Force operations would be enhanced, improved, or otherwise assisted by the unit. A BEST unit with a port security nexus must be composed of at least one member of: (1) the Coast Guard Investigative Service, and (2) the geographically responsible Coast Guard Sector Intelligence Office. The bill modifies the DHS annual reporting requirement on the BEST program to require:: a description of the effectiveness of BEST in disrupting and dismantling transnational criminal organizations and reducing child exploitation; an assessment of how BEST enhances information-sharing; a description of how BEST advances DHS's homeland and border security strategic priorities and effectiveness of BEST in achieving related objectives; an assessment of BEST's joint operational efforts with departmental Joint Task Force operations; an assessment of whether additional authorities are needed to accomplish the BEST mission; an assessment of whether additional Memos of Understanding are needed to address intelligence and coordination gaps; and an assessment of whether funding has an impact on the overall mission of BEST operations to assist in advancing DHS's homeland and border security priorities and related objectives. (Sec. 3) The bill expresses the sense of Congress that providing personnel danger pay to U.S Immigration and Customs Enforcement (ICE) agents who are assigned to dangerous overseas posts will: (1) help modernize ICE's overseas workforce compensation system, and (2) place ICE on equal footing with the law enforcement agencies of the Department of Justice. The Department of State may not deny a request by the Drug Enforcement Administration, the Federal Bureau of Investigation, or ICE to authorize a danger pay allowance for any employee of such agencies. ICE must submit a report to the congressional foreign affairs and homeland security committees that specifies the overseas posts that have been designated as locations at which ICE agents will receive a danger pay allowance and the justification for each such designation.