Senior Security Engineer

CoStar Group•Arlington, VA

1d•Hybrid

About The Position

CoStar Group is expanding its enterprise Data Loss Prevention (DLP) program and is seeking a Senior DLP Engineer. This role involves designing, scaling, and operationalizing Microsoft Purview-based protections across endpoints and Microsoft 365 workloads. The Senior DLP Engineer will collaborate with Security Operations, Governance, Risk & Compliance (GRC), Legal/Privacy, and various business units. Key responsibilities include owning the technical strategy, architecture, deployment, and ongoing operations of Microsoft Purview, developing sustainable detection and prevention capabilities for data exfiltration and misuse, integrating DLP with enterprise workflows such as incident response, exception management, and change control, and providing clear metrics and executive reporting. The position offers a hybrid work model and can be based in Arlington, VA or Richmond, VA.

Requirements

Bachelor’s Degree required from an accredited, not for profit university or college.
A track record of commitment to prior employers.
6+ years in information security with 3–5+ years focused on enterprise DLP.
Hands‑on expertise deploying and operating Microsoft Purview Information Protection & DLP at 5k+ user scale, including Endpoint DLP and M365 workloads.
Practical experience with sensitivity labels, automatic and manual labeling, Sensitive Information Types, Exact Data Match (EDM), and trainable classifiers.
Proficiency with Kusto Query Language (KQL), PowerShell, and API/automation for policy management and reporting.
Experience integrating DLP with SIEM/SOAR, SOC runbooks, and incident/alert handling processes.
Strong stakeholder skills: partnering with Legal/Privacy, HR, Compliance, and business units; clear documentation and change management.
Working knowledge of data governance and regulatory drivers (e.g., SOX ITGC, PCI, HIPAA, GDPR/CCPA) as they relate to DLP and monitoring.

Nice To Haves

Track record accelerating a Microsoft Purview rollout from pilot to enterprise adoption, with measurable risk reduction.
Experience with Defender for Cloud Apps integration, Defender XDR signal correlation, and Endpoint platform integrations (Intune, Windows, Mac).
Knowledge of Microsoft Information Protection (MIP) SDK, Power Automate, or Graph APIs to extend labeling and DLP workflows.
Certifications: SC‑400 (Microsoft Information Protection Administrator), SC‑200 (Security Operations Analyst), SC‑100 (Cybersecurity Architect), or IAPP (CIPM/CIPP).

Responsibilities

Own the enterprise DLP architecture and roadmap using Microsoft Purview across Exchange Online, SharePoint Online, OneDrive, Teams, Power BI, and Endpoint DLP on managed devices.
Design and implement data classification and labeling at scale (sensitivity labels, automatic/manual labeling, protection actions) aligned to the organization’s data taxonomy.
Build, test, and tune DLP policies for high‑risk exfiltration vectors (email, cloud storage, chat, web uploads, endpoints: removable media, print, clipboard, Bluetooth, RDP, browser downloads).
Stand up and mature advanced classifiers and detections (Sensitive Information Types, Exact Data Match schemas, trainable classifiers) with continuous improvement cycles.
Integrate DLP with incident management and SOC workflows (alert triage, case management, evidence capture, automation) and with SIEM (e.g., Microsoft Sentinel) using KQL analytics.
Partner with Identity, Endpoint, and Collaboration teams to enforce device/user trust prerequisites, and with Compliance/Legal on retention, eDiscovery, and privacy-by-design.
Create enablement content: policy tips, just‑in‑time guidance, and training for end users and privileged administrators to reduce friction and false positives.
Establish exception and change management processes, including time‑bound exceptions with compensating controls and periodic recertification.
Publish dashboards and KPIs to leadership (coverage, alert volumes, true‑positive rates, MTTR, prevented exfiltration, policy drift).
Mentor junior engineers and act as the primary subject‑matter expert for Microsoft Purview DLP.

Benefits

Generous compensation and performance-based incentives.
Internal training.
Tuition reimbursement.
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.
On-site fitness center and/or reimbursed fitness center membership costs (location dependent), with yoga studio, Pelotons, 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.