Lead Detection & Response Platform Engineer

Lead Detection & Response Platform Engineer Job Description 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, 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. In this role, you will own and engineer the platform that CoStar Security uses to triage alerts and respond to incidents. That platform covers the SIEM, XDR, SOAR and case-management tools, and the integrations, automation and content that connect them. You will define how alerts are triaged, investigated and escalated, and then build those processes into the platform so they run the same way every time. You will also explain security concepts and decisions clearly to technical and non-technical audiences across the CoStar Enterprise. This is not a tool administration role, and it is not a software engineering role. You will set the standards for triage and incident response, measure how well the platform supports them, and improve both the process and the platform based on that data. You will mentor analysts and engineers so they can design and automate their own work. You will also coordinate incident response across the business. The successful candidate understands security operations well enough to define how the work should be done, and has the engineering skills to make the platform do it. This position can be located in Arlington or Richmond, VA and is in office Monday through Thursday and work from home on Friday. Responsibilities

• Own the alert triage process: define how alerts are classified, enriched, prioritized, investigated, escalated and closed, and write these as standards that analysts can follow and that can be audited.
• Build those processes into automation: SOAR playbooks, enrichment pipelines and case-management workflows that remove repetitive analyst work and make handling consistent.
• Run the detection and response stack (SIEM, XDR, SOAR, case management) as a platform, keeping its configuration, content and integrations under version control with peer review, testing and automated deployment.
• Measure triage and response performance (alert volume, true and false positive rates, time to triage and contain, and automation coverage) and use the data to decide what to tune, automate or retire.
• Work with detection engineering and threat intelligence so every new detection ships with triage guidance, enrichment and response actions, and lessons from triage feed back into tuning.
• Evaluate AI- and LLM-assisted triage, enrichment and case summaries, and adopt them only where they measurably cut analyst effort, with human review and defined guardrails.
• Coordinate incident response across business units: lead significant incidents, coordinate technical, business and legal stakeholders, and follow post-incident corrective actions through to completion.
• Maintain the Incident Response Plan and run quarterly tabletop exercises, turning the findings into updated playbooks and automation.
• Mentor and develop analysts and engineers in process design, investigation methods and automation; review their playbooks, queries and code so the team can build its own automation rather than depend on one person.
• Connect identity, endpoint, cloud, email and network telemetry and tools through APIs, and close the data-quality and coverage gaps that slow triage down.
• Use MITRE ATT&CK to map detection and response coverage and set threat hunting priorities.
• Take part in a 24x7 on-call rotation.

Basic Qualifications

• Bachelor’s Degree required from an accredited, not for profit, in person, university or college.
• A track record of commitment to prior employers
• One or more security certifications (e.g., GIAC GCIH, GCDA, CISSP, CISM, ECIH)
• 8+ years in IT, including 5+ years in cybersecurity and at least 3 years in security operations, detection engineering or incident response
• Has designed and run alert triage or incident response processes for an enterprise security operations team
• Has built and maintained production security automation in a SOAR or workflow platform: playbooks, API integrations and enrichment
• Proficient in Python or PowerShell, and in working with REST APIs and JSON
• Proficient in at least one SIEM query language (e.g., KQL, SPL)
• Has managed security content or configuration with Git and a change-control process
• Has investigated across identity (Active Directory / Entra ID), endpoint, cloud and email telemetry

Preferred Qualifications and Skills

• Microsoft security stack: Sentinel, Defender XDR, Logic Apps, Entra ID
• Detection-as-code or CI/CD pipelines for SIEM content; infrastructure as code (Terraform, Bicep/ARM)
• Investigating in Azure and AWS, including cloud security posture tools
• Has used LLMs in security workflows and can explain their limits and failure modes
• Has defined security operations metrics and reported them to leadership
• Working knowledge of NIST SP 800-61, MITRE ATT&CK and a SOC maturity model (e.g., SOC-CMM)
• A record of mentoring staff or building internal training
• Clear technical writing: runbooks, standards and post-incident reports

What’s in it for You When you join CoStar Group, you’ll experience a collaborative and innovative culture working alongside the best and brightest to empower our people and customers to succeed. We offer you generous compensation and performance-based incentives. CoStar Group also invests in your professional and academic growth with internal training, and tuition reimbursement. Our benefits package includes (but is not limited to):

• 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)
• Access to CoStar Group’s Employee Resource Groups
• Complimentary gourmet coffee, tea, hot chocolate, fresh fruit, and other healthy snacks

The final salary or hourly rate offered for this role will fall within the range set forth below based on a variety of factors, including but not limited to, geographic location, skills, and competencies. Base Compensation: $155,000 – $245,000 Annually 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-AR CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing