Senior Systems Security Engineer

Job Description

About CoStar Group

CoStar Group (NASDAQ: CSGP) is a leading global provider of commercial and residential real estate information, analytics, and online marketplaces. Included in the S&P 500 Index and the NASDAQ 100, CoStar Group is on a mission to digitize the world's real estate, empowering all people to discover properties, insights and connections that improve their businesses and lives. 

We have been living and breathing the world of real estate information and online marketplaces for over 35 years, giving us the perspective to create truly unique and valuable offerings to our customers. We've continually refined, transformed, and perfected our approach to our business, creating a language that has become standard in our industry, for our customers, and even our competitors. We continue that effort today and are always working to improve and drive innovation. This is how we deliver for our customers, our employees, and investors. By equipping the brightest minds with the best resources available, we provide an invaluable edge in real estate.

About Domain

Domain is a leading property technology and services marketplace that is home to one of the largest portfolios of property brands in Australia, including the Domain, Allhomes and Commercial Real Estate (CRE) platforms. In 2025, Domain became part of CoStar Group (NASDAQ: CSGP), a global leader in commercial real estate information, analytics, online marketplaces and 3D digital twin technology. Together, Domain and CoStar Group is dedicated to digitising the world's real estate, empowering all people to discover properties, insights, and connections that improve their businesses and lives.

Senior Systems Security Engineer reporting to Head of Networks and Security Operations. This is a pivotal role where you will be responsible for the design, development, and implementation of automation solutions across our critical platforms. Specifically networking, identity, and endpoint protection. You will play a crucial role in hardening defensive capabilities across the entire business, ensuring our infrastructure is robust, resilient, and ready for future scale.

What you'll be doing

• Play a lead role in Domain's Zero Trust initiative through design workshops and the implementation of essential tools and integrations.

• Designing and implementing automation for network, identity, and endpoint protection security controls across all Domain assets (facilities, physical, and cloud).

• Implementing automation solutions for the configuration management of on-premise and cloud firewall appliances.

• Managing endpoint protection agents and their integrations with SASE and identity providers.

• Providing expert consultative assistance to Product and Tech teams on networking design, ensuring alignment with security guidelines and principles.

• Managing user access control within our network environments.

• Troubleshooting and supporting network security infrastructure across on-premise, cloud, and hybrid environments, including SASE/SSE frameworks, secure remote access gateways, and firewalls. Troubleshooting and supporting network security infrastructure across on-premise, cloud, and hybrid infrastructure.

What success looks like

• A cohesive and consistent user experience across all platforms, networks, and identity access 

• Continual improvement of security hardening and identity access management

• A strong connection between network and systems security that provides excellent end user experience 

Experience & Technical Knowledge

• Tertiary qualifications in Computer Science, Software Engineering, Cybersecurity, or a related field.

• Solid understanding of identity and access management (IAM) principles.

• Deep understanding of network security principles and various firewall technologies.

Preferred Qualifications and Skills 

• Relevant security or vendor certifications (e.g., Palo Alto).

• Proficiency in configuration management automation tools and practices (e.g., Terraform, Ansible, CI/CD pipelines, Python).

• Expertise in scripting languages (Python, Bash, PowerShell).

• Strong knowledge of network protocols (TCP/IP, DNS, DHCP, VXLAN, VPN, BGP, OSPF).

Why join us?

We're the kind of place you can make a real impact, with a workplace culture where you can be you. It's a fun, safe space where you'll always feel you belong. Perks of the role include:

• Hybrid working; 

• First-rate parental leave;

• Continuous opportunities to leap, learn and grow in a team that values creativity and innovation;

We don't just talk, we do. Every day we solve property problems for Australians and beyond. We encourage our people to see the possibilities, and turn them into realities. 

What's next?

We'll give your application the thoughtful attention it deserves and get back to you as soon as possible. If there's a match, one of our recruitment consultants will reach out so keep your phone handy We're genuinely excited about the chance to work together and make a meaningful impact.

Equity, Diversity and Inclusion at Domain

Domain is enthusiastically and unapologetically committed to fostering an equitable, inclusive work culture which reflects our customers and communities. We are proactively looking for candidates from all lived experiences, including people with disability, and people of all ages, ethnicities, cultures (including Aboriginal and Torres Strait Islander Peoples), faiths, sexual orientations, and gender identities (including trans and non-binary people).

We are committed to providing an equitable recruitment process for people with disability. If you require adjustments during the process we're here to support. If you wish to receive this job advertisement in an accessible format, or have a confidential chat about workplace adjustments, please contact our Equity, Diversity and Inclusion team at or leave a message on and we will get back to you. 

CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing