With rising cyberattack frequency and range, Quantum Computing companies, institutions and research groups may become targets of nation state actors, cybercriminals and hacktivists for sabotage, espionage and fiscal motivations as the Quantum computing race intensifies. Quantum applications have expanded into commercial, classical information systems and services approaching the necessity to protect their networks, software, hardware and data from digital attacks. We proceed to outline threat vectors for quantum computing systems and the respective defensive measures, mitigations and best practices to defend against the rapidly evolving threat landscape. We subsequently propose recommendations on how to proactively reduce the cyberattack surface through threat intelligence and by ensuring security by design of quantum software and hardware components.