Network Security Engineer

Network Security Engineer

About Millennium
Millennium is a global, diversified alternative investment firm, founded in 1989. Defined by evolution, innovation and focus, Millennium's mission is to deliver results for our investors. Our people are empowered with both independence and support: the autonomy to pursue ideas with conviction and the backing of a global network committed to collaboration, disciplined risk management and continuous learning. With opportunities to deepen expertise and accelerate development, talent at Millennium is equipped to adapt, evolve and build lasting impact over time. Discover how transformative growth accelerates impact.

Meet the Team
Technology is core to the health and growth of our business. The firm's active, multi-manager business model demands flexible, scalable technology and advanced proprietary systems, including the development of the next generation of analytical and trading capabilities. Millennium's Information Security team protects the firm's people, data, and technology across a complex, fast-moving global trading environment, partnering closely with technology, trading, and business stakeholders to embed security into every aspect of our global operations. As the firm accelerates its use of artificial intelligence, the team is equally focused on applying AI in innovative, entrepreneurial ways to strengthen our own defenses. Within that organization, the Network Security team designs and defends the network infrastructure connecting Millennium's global offices, data centers, and cloud environments, spanning perimeter controls such as firewalls, IDS/IPS, NDR, NAC, proxies, email security, and DNS security, as well as the detection and automation stack behind them, including the security data lake, logging pipelines, and SOAR automations. This is a growing organization that combines deep technical expertise with pragmatic risk management to keep pace with the speed and scale of the firm's business.

What You'll Do
• Design, implement, and maintain network security controls, including firewalls, segmentation, secure remote access, intrusion detection and prevention, network detection and response, and network access control, and support secure network architecture for new offices, data centers, and cloud connectivity.
• Build and maintain the logging pipelines and security data lake that power detection across the environment.
• Develop, implement, and maintain security policies, procedures, and standards across network security, email security, DNS security, and the security data lake.
• Strengthen perimeter security through automation, improved monitoring, vulnerability identification, and actionable alerting and reporting.
• Monitor, manage, and analyze security logs, alerts, and events across multiple systems to identify threats, vulnerabilities, and suspicious activity, and tune network infrastructure to reduce risk while minimizing business disruption.
• Apply AI to the team's own work, accelerating investigation, automation, detection engineering, and reporting, and help secure the firm's use of AI models, tools, and frameworks.
• Provide security engineering and consulting support to Security Operations and the wider Information Security organization, and partner with stakeholders across Technology, Trading, Legal, Internal Audit, and Compliance to support and enforce security policies and controls.
• Conduct system audits and vulnerability assessments, manage remediation efforts and findings from audits, penetration tests, and process reviews, participate in incident response for network-related events, and use threat intelligence to sharpen detection, defense, and response.

What You Bring
• 5+ years of hands-on network security experience, ideally within financial services, hedge funds or other buy-side firms, or another highly regulated industry.
• Hands-on experience administering enterprise network security infrastructure, including firewalls, VPN, proxies, intrusion detection and prevention, network detection and response, and network access control, with a practical understanding of proxy engineering concepts.
• Proven experience as a security engineer with hands-on expertise in logging pipelines, data lakes, or SIEM platforms such as Splunk, ELK, Sentinel, or S3/Athena, plus SOAR automation; experience with breach and attack simulation tooling is a plus.
• Hands-on AI experience, both using AI tooling in day-to-day security work and securing the use, deployment, and governance of AI models, tools, and frameworks.
• Strong command of core networking and infrastructure concepts, including TCP/IP, routing, switching, segmentation, DNS, Wi-Fi, and virtualization, along with email and DNS security controls and packet capture and network analysis tools such as tcpdump, Wireshark, or ngrep.
• Experience securing hybrid on-premises and cloud network architectures, with working knowledge of AWS, GCP, or Azure and proficiency across Windows, Linux, macOS, and container environments such as Docker and Kubernetes.
• Scripting or development skills in Python, PowerShell, Bash, or similar languages, with the ability to troubleshoot complex network and security issues under time pressure, operate independently in a fast-paced, high-stakes environment, and communicate clearly with both deeply technical teams and senior executive stakeholders.
• Bachelor's degree or higher in Computer Science, Computer Engineering, Cybersecurity/Information Security, or a related field, or commensurate work experience; certifications such as CISSP, GCIA, CISM, CCNP Security, Palo Alto PCNSE, or Fortinet NSE are valued.