Senior Identity Security Engineer (Arlington, VA or San Diego, CA)

Senior Identity Security Engineer (Arlington, VA or San Diego, CA)
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Job Description
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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. 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'll harden controls to empower 8000 employees to seamlessly and securely connect to company resources through a zero trust, FIDO2 compliant framework. You will assess, identify and mitigate risks across a large technical infrastructure and corporate environment. This position will work with Security, Systems, DevOps, Network, and Development teams to drive and shape the way our employees and engineers access our systems. This is an identity security engineering role rather than an IAM administration role: the candidate must have hands-on experience finding and eliminating identity attack paths, detecting identity-based attacks, and continuously validating the security of modern IAM platforms. Ideal candidates will have a thorough understanding of adversary in the middle attacks, token theft, social engineering attacks, and offensive privilege escalation techniques across Active Directory and Entra ID and have experience implementing or operating controls to prevent and detect such attacks.
This position can be in either Arlington, VA or San Diego, CA and is in office Monday through Thursday and work from home on Friday.
Responsibilities
Design, implement, and continuously improve identity security controls across various platforms
Harden Tier 0 identity infrastructure, including domain controllers, AD CS, Entra Connect, and privileged roles, in line with Microsoft’s Enterprise Access Model
Develop and maintain conditional access policies that enforce appropriate authentication strength, device compliance, etc including for privileged roles, sensitive applications, and workload identities
Analyze logs to scope and guide rollouts of new security initiatives
Support an org-wide, multi-platform phish-resistant authentication rollout
Engineer controls around AI and workload identities (service principals, managed identities, OAuth app registrations)
Research, prototype, and operationalize AI-assisted tooling and agentic workflows to improve team efficiency, including automating repetitive analysis and building internal tools that surface identity risk
Document projects, standards, and runbooks
Communicate frequently and effectively with both technical and non-technical stakeholders
Drive attack path management across Active Directory and Entra ID using commercial and open-source tools such as BloodHound (Enterprise or Community Edition) and AzureHound, prioritizing and remediating the paths that lead to Tier 0
Engineer, tune, and validate identity threat detections across Microsoft Defender for Identity, Entra ID Protection, and Okta, and partner with the SOC on identity-based incident response
Continuously validate identity configuration and catch drift with automated security testing, such as Maester for Entra ID and Microsoft 365
Stay current with the greater identity threat landscape as well as the identity defense offerings from major IDP vendors
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
Thorough understanding of AitM attacks (e.g., Evilginx) and token theft, and how to neutralize them through phish-resistant authentication, token protection, and strong identity security hygiene
4+ years of hands-on security engineering experience, including implementation of new controls to address threats
Strong analytical and problem-solving skills with a data-driven approach to decision-making
Hands-on experience securing and hardening industry-standard IDPs (Okta, PingID, Microsoft Entra ID, Active Directory)
Knowledge of authentication and authorization protocols such as SAML, OAuth, OIDC, Kerberos
Working knowledge of how attackers abuse identity systems, such as Kerberoasting, DCSync, AD CS (ESC) abuse, illicit OAuth consent grants, and privilege escalation through Entra roles and app permissions, and the controls that prevent and detect each
Firm understanding of PKI, the FIDO2 framework, passkeys, Windows Hello for Business, and Platform SSO, Okta FastPass, Okta Device Trust
Solid understanding of role-based access control, least privilege, just-in-time access, and other identity security paradigms
Experience analyzing identity telemetry (Entra sign-in and audit logs, domain controller events, MDI alerts) in a SIEM, writing hunting and detection queries (e.g., KQL), and creating related dashboards
Ability to read and author basic scripts in at least one common language (Python, PowerShell, Bash)
Preferred Qualifications and Skills
Hands-on experience with one or more of the following, with examples of identity risks you found and remediated by using them: Microsoft Defender for Identity (MDI), SpecterOps BloodHound and AzureHound, or Maester
Hands-on experience with Microsoft Intune, Jamf, JumpCloud, or other MDM platforms
Experience with offensive identity tooling such as SharpHound, Responder, Rubeus, Certipy, or ROADtools, used to validate defensive controls
Record of automating operational tasks
Familiarity with CI/CD infrastructure
Experience configuring risk-based conditional access or authentication policies
Experience with workload identity governance
Strong written and verbal communications skills, with a demonstrated ability to communicate complex topics with both engineering peers and non-technical audiences
Experience with AI/ML-assisted security tooling, including building or deploying LLM-based agents
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: $133,000 – $203,000 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.
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CoStar Group is an Equal Employment Opportunity Employer; we maintain a drug-free workplace and perform pre-employment substance abuse testing