Sr. Security Engineer

Overview

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. By equipping the brightest minds with the best resources available, we provide an invaluable edge in real estate.

Responsibilities

• Network & Cloud Security : Provide engineering expertise to ensure enterprise network changes are designed and implemented securely (on‑prem and cloud). Audit existing network designs and infrastructure configurations and recommend improvements to security posture. Evaluate firewall change requests across on‑premise and cloud environments. Design, enforce, and audit policies for Next Generation Firewalls (NGFW), load balancers, routers, switches, and wireless infrastructure. Manage Secure Service Edge (SSE) platform.
• SaaS Security : Partner with application owners and third‑party risk teams to review SaaS security architecture and control effectiveness. Operate and tune SaaS security tooling (e.g., CASB/SSE capabilities) to detect risky behavior, misconfigurations, and data exfiltration paths. Define and enforce SaaS security standards for logging, identity integration, and least‑privilege access. Support SaaS incident investigation and remediation efforts in coordination with legal, privacy, and compliance teams. Develop reusable SaaS security review patterns and documentation for engineering and procurement teams.
• AI & Emerging Technology Security : Assess security risks associated with AI platforms, copilots, and agent‑based systems, including model access controls, prompt/data leakage risks, and tool/plugin abuse. Partner with engineering teams to design security controls for AI‑assisted workflows and developer tools. Contribute to governance models for AI usage, including enforcement of network, identity, and data security boundaries. Monitor AI‑related telemetry and logs to identify anomalous behavior, data exposure, or misuse patterns. Support threat modeling and risk assessments for AI integrations with enterprise systems and SaaS platforms. Stay current on AI security threats, abuse patterns, and control frameworks, translating them into actionable enterprise safeguards.

Basic Qualifications

• Bachelor’s Degree is required from an accredited, not for profit, in‑person university or college.
• 5+ years of experience in Information Security or Security Engineering.
• One or more industry‑recognized certifications (e.g., CISSP, SANS/GIAC, CCNA, equivalent).
• Strong experience securing AWS networking (NACLs, Security Groups, ALB/NLB, Transit Gateway, Network Firewall).
• Hands‑on experience with NGFWs, WAFs, load balancers, and enterprise network segmentation.
• Strong scripting or automation skills (Python, PowerShell, or similar).
• Deep understanding of subnetting, routing, and network isolation principles.
• Experience with SaaS security platforms, CASB, or SSE tooling.

Preferred Qualifications and Skills

• Familiarity with identity‑driven security models (SSO, OAuth, API tokens, service principals).
• Working knowledge of Azure DevOps, Terraform, or infrastructure‑as‑code workflows.
• Experience operating in large, complex enterprise environments.
• Ability to produce high‑quality technical documentation and security standards.
• Strong communication and collaboration skills across technical and non‑technical teams.
• Exposure to AI systems, model‑assisted tooling, or developer copilots in an enterprise context.

What’s in it for You

• Comprehensive healthcare coverage: Medical / Vision / Dental / Prescription Drug
• Life, legal, and supplementary insurance
• Virtual and in‑person mental health counseling services for individuals and family
• Commuter and parking benefits
• 401(K) retirement plan with matching contributions
• Employee stock purchase plan
• Paid time off
• Tuition reimbursement
• On‑site fitness center and/or reimbursed fitness center membership costs (location dependent), with yoga studio, Peloton, personal training, group exercise classes
• Access to CoStar Group’s Diversity, Equity, & Inclusion Employee Resource Groups
• Complimentary gourmet coffee, tea, hot chocolate, fresh fruit, and other healthy snacks

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

We welcome all qualified candidates who are currently eligible to work full‑time in the United States to apply. However, please note that CoStar Group is not able to provide visa sponsorship for this position. #LI-KW1

CoStar is committed to creating a diverse environment and is proud to be an equal opportunity workplace and affirmative action employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status.

CoStar is also committed to compliance with all fair employment practices regarding citizenship and immigration status. If you are a qualified individual with a disability or a disabled veteran, you may request a reasonable accommodation if you are unable or limited in your ability to use or access as a result of your disability. You can request reasonable accommodations by calling or by sending an email to