Senior Security Engineer, x15ventures  

6 months fixed term contract 

Location: Sydney 

Hybrid working - 50 / 50 office

 

Who we are 

We’re a venture-scaler powered by CommBank. That means we build, buy, and invest in startups that could benefit the bank’s 15 million customers and beyond. 

Because of what we do, we’re really neither corporate, nor startup – instead we’re happily navigating the space between both worlds. We're close enough to benefit from the bank’s strategy, scale, and stability, but separate enough that we have the autonomy to try new things. 

 

What it’s like to work here 

We’re a community of galvanisers, thinkers, and doers. We have a big, bold vision, which so far no-one has nailed (including us). That excites, rather than deters, us.   

We never lose sight of the impact we can have on people’s lives, and the role that each of us plays in shaping the bank of the future. We don’t take ourselves too seriously and make time to connect to celebrate and grow our people. 

At x15, we’re guided by three values: Care, courage, and commitment. And what does that mean? We’re aware, attuned, and always act to help our people and our customers. We’re more than just job titles and we don’t hide the human stuff. We lead with grit and grace and do what's right – even if it's hard. And, whatever happens, we always find a way. 

 

Where do you fit? 

As a Senior Security Engineer, you’ll be a key technical contributor helping to strengthen cyber, fraud and scams security across our ventures.
You’ll work closely with venture teams, shape practical security solutions, and lead hands-on work ranging from threat hunting and detection tuning to building automation into SOC playbooks and uplifting security practices across the portfolio.

You’ll make a major impact on how we detect, respond and assure security across multiple ventures; while helping us scale a modern, lightweight and startup-friendly security function.

In this role you will 

• Security Assurance – Help build and maintain lightweight, effective security assurance programs aligned to NIST CSF and ACSC Essential 8.
• SOC & Threat Hunting – Perform threat hunting, support purple team exercises, and work hands-on with Microsoft Sentinel and the Defender Suite.
• Automation First – Implement automated playbooks, streamline repetitive SOC workflows, and improve detection and response efficiency.
• Architecture & Consultation – Partner with engineers and product teams to embed secure design patterns and provide actionable, pragmatic security advice.
• Mentorship – Share knowledge, support junior engineers, and help uplift security capability across teams.
• Reliability Mindset – Apply reliability-focused thinking to improve the resilience and observability of security tooling and systems.
• Continuous improvement – Support maturity uplift across ventures by contributing to threat models, security assessments and cross-venture improvement initiatives.

We are interested to hear from people who have  

• Strong experience in cyber security with exposure to fraud and scams prevention.
• Hands-on expertise with Microsoft Sentinel and the Defender XDR suite, including practical threat-hunting work.
• Solid SOC foundations: incident response, detection engineering and threat hunting.
• Experience informally mentoring peers or helping uplift team capability.
• A passion for automation-driven security operations (SOAR, scripted playbooks, automated remediation).
• Familiarity with NIST frameworks, Essential 8 maturity and modern threat-assessment approaches.
• A purple-team mindset — able to think like an attacker and respond like a defender.
• Strong communication skills, with the ability to translate security concerns for product teams, risk partners and executives.  

Desired skills: 

• Familiarity with applying SRE-style practices to security systems.
• Experience contributing to assurance activities (audits, control testing, RCSA).
• Experience in cloud-native, zero-trust environments (Azure, AWS, SaaS-heavy).
• Background in startup or scale-up environments balancing pragmatism with control uplift.

Why Join Us? 

•  Enjoy a flexible and dynamic startup environment 
• We nurture a safe space for our people to show up as they are! 
• Competitive salary and bonus structure 
• Opportunities for professional growth and development 
• Access to the best in class benefits that CommBank offers. 

We look forward to hearing from you! 

Advertising End Date: 11/12/2025