Our client is a pioneering sovereign defence technology provider, supporting Australia's national security through cutting-edge engineering and cyber solutions. Known for its technical excellence, collaborative environment, and mission-led purpose, the organisation is expanding its Cyber Security capability during a period of rapid growth and investment in digital transformation. With significant investment in cloud transformation and infrastructure modernisation, they offer a unique opportunity to contribute to projects of national significance. The Opportunity This is a rare opportunity to join a dedicated Cyber Security team in a permanent, Canberra-based role where your work directly protects systems of national importance. You'll be contributing directly to secure-by-design infrastructure, next-generation threat detection capabilities, and streamlined response automation. You will play a critical role in cyber defence, threat detection, response, and incident resolution across complex, classified environments. The Role As the Cyber Security Assurance Specialist, you’ll oversee the compliance and technical security posture of high-assurance classified systems. You'll also coordinate with external agencies and security authorities to ensure accreditation and monitoring frameworks are upheld. Your key responsibilities include: Act as the ISSO for assigned classified ICT systems Lead system security compliance, monitoring and documentation Drive accreditation activities aligned to DISP, ISM, DSPF, and NIST Manage risk assessments, vulnerability analysis, and audit readiness Support hardware/software security configuration and change control Task and oversee sysadmins/security admins for assigned systems Provide cyber assurance advice to senior management and projects Act as Deputy ISSM as required The Ideal Person You're a seasoned cyber security or system assurance professional with over 5 years’ experience in secure government environments, holding a Positive Vetting (PV) clearance and bringing deep expertise in frameworks like ISM, DISP, DSPF or NIST, along with strong skills in compliance, accreditation, risk management, and the ability to influence and communicate effectively across technical and non-technical teams. A passion for national security and a collaborative approach to problem solving will set you up for success in this role. You must be an Australian citizen, and an active Positive Vetting security clearance is must have for this role. Salary / Rate $140k - $158k 14% Super 6 weeks of annual leave Free parking How to Apply To apply online, please click on the appropriate link. Alternatively, for a confidential discussion, please contact Prajjwal or Antony on 02 6108 4878 quoting ref no. 20874 HorizonOne is committed to building a diverse and inclusive workforce and we encourage applications from people of all cultures, capabilities and backgrounds.