Defending American Security from Kremlin Aggression Act of 2018 This bill imposes limits on any U.S. withdrawal from the North Atlantic Treaty Organization (NATO), amends provisions related to cybercrimes, and imposes sanctions on Russian individuals involved in various activities. No funds may be used to withdraw the United States from NATO unless the Senate passes a resolution consenting to the withdrawal. The bill also authorizes expedited transfers of excess defense articles to NATO member countries. This bill establishes in the Department of State the Office of Cyberspace and the Digital Economy, to serve as the lead policy body on issues including international cybersecurity and Internet freedom. Offenses relating to the manufacture, distribution, and possession of communication-intercepting devices shall be unlawful under federal anti-money laundering laws. It shall also be a crime to intentionally traffic in the means to access protected computers, including computers that are part of a voting system. Property related to such crimes, including proceeds gained from the crime, shall be subject to criminal and civil forfeiture. The President shall impose sanctions (1) on Russian individuals and entities that facilitate or benefit from Russian President Vladimir Putin's corruption, and (2) on those that knowingly engage in significant financial transactions with individuals that support or facilitate Russian malicious cyber activities. The bill also imposes sanctions for supporting various other Russia-related activities, including Russian interference in democratic processes. The bill establishes requirements for reporting on a wide variety of matters concerning Russian economic, military, and political activities.