Department of Homeland Security Data Framework Act of 2018 This bill directs the Department of Homeland Security (DHS) to (1) develop a data framework to integrate existing DHS datasets and systems for access by authorized personnel in a manner consistent with relevant legal authorities and privacy, civil rights, and civil liberties policies and protections; (2) ensure that all information of a DHS office or component that falls within the scope of the information sharing environment, and any information or intelligence relevant to priority mission needs and capability requirements of the homeland security enterprise, is included; and (3) ensure that the framework is accessible to DHS employees who have an appropriate security clearance, who are assigned to perform a function that requires access, and who are trained in applicable standards for safeguarding and using such information. DHS shall (1) issue guidance for DHS employees authorized to access and contribute to the framework that enforces a duty to share between DHS offices and components for mission needs, and (2) promulgate data standards and instruct DHS components to make available information through the framework in a machine-readable format. DHS may exclude information that could jeopardize the protection of sources, methods, or activities or compromise a criminal or national security investigation. DHS shall incorporate into such framework systems capabilities for auditing and ensuring the security of information. Such capabilities shall include mechanisms for identifying insider threats and security risks and safeguards for privacy, civil rights, and civil liberties.