Active Directory L3 Support Engineer

Apptoza Inc.; Toronto; On-site; CAD 110,000 - 150,000; Full time

Job summary

Apptoza Inc. is seeking an experienced Active Directory Engineer to strengthen and modernize directory services across production and disaster recovery environments in Toronto.

You will manage domain controller expansion, enhance authentication controls, and harden Group Policy and network configurations to reduce attack paths. You will lead efforts to replace legacy DCs, implement Zero Trust-aligned identity services, and maintain health of replication, DNS, and policy processing across

Qualifications

• Hands-on experience administering Active Directory Domain Services in multi-domain environments.
• Strong knowledge of domain controllers, replication, DNS, Group Policy, and AD authentication.
• Experience with security controls such as EPA, LDAP signing, channel binding,Kerberos hardening.

Responsibilities

• Deploy and configure additional domain controllers across primary and disaster recovery sites to improve availability.
• Replace legacy Windows Server 2016 domain controllers and support modernization with minimal service disruption.
• Implement production and development network segmentation to align identity services with Zero Trust principles.
• Maintain AD health across replication, authentication, DNS integration, and Group Policy processing.

Skills

Active Directory

Domain Controllers

PowerShell

Group Policy

AD Security

Kerberos

LDAP signing

NTLM

Tools

AD CS

ADWS

DNS

Windows Server

PowerShell

Job description

This role is responsible for strengthening and modernizing Active Directory services across production and disaster recovery environments. The engineer will manage domain controller expansion and replacement, improve authentication and directory security controls, remediate privileged-access weaknesses, and harden Group Policy and network configurations to reduce attack paths and support resilient enterprise identity services.

Key Responsibilities

Deploy and configure additional domain controllers across primary and disaster recovery sites, including DC01 and DC02, to improve availability, resilience, and site-level recovery readiness.

Replace legacy Windows Server 2016 domain controllers and support platform modernization activities with minimal service disruption.

Implement production and development network segmentation to reduce lateral movement risk and align identity services with Zero Trust principles.

Maintain Active Directory health across replication, authentication, DNS integration, and Group Policy processing.

Security Hardening and Access Control

Enable Extended Protection for Authentication (EPA) and require SSL/TLS for privileged HTTP‑based services such as AD CS and ADWS to reduce credential relay and man‑in‑the‑middle exposure.

Enforce SMB signing to help prevent tampering and NTLM relay over SMB sessions.

Disable NTLMv1 and strengthen LDAP protections by enforcing LDAP signing and channel binding / LDAPS for directory communications.

Implement Kerberos armoring, restrict unconstrained delegation, tighten delegation permissions on privileged accounts, and address unknown delegation entries.

Remediate excessive privilege findings, including AdminCount issues, GPO‑deployed file exposure, missing protective ACLs, and privileged accounts not enrolled in Protected Users.

Remove insecure legacy access patterns such as Pre‑Windows 2000 compatible group usage and administrator logon allowances through Group Policy.

Enforce stronger password and privileged account controls, including a 12‑character minimum complexity baseline, password expiration where appropriate, and smartcard password rotation requirements.

Identify and remediate risky account configurations such as PASSWD_NOTREQD, password never expires, admin accounts with email usage, and missing delegation restrictions.

Group Policy, Logging, and Compliance

Harden Group Policy baselines by enforcing event audit logging, PowerShell logging, supported encryption types, remote desktop best‑practice settings, and secure administrator sign‑in controls.

Review and remediate LDAP signing and channel binding gaps, privileged HTTP service protection gaps, and other domain‑level weak configurations identified through assessments.

Document remediation plans, implementation standards, and operational procedures to support audit readiness and ongoing compliance.

Partner with infrastructure, cybersecurity, and application teams to validate compatibility, sequence change windows, and reduce operational risk during security enforcement activities.

Required Technical Skills

Hands‑on experience administering Active Directory Domain Services in multi‑domain or multi‑site enterprise environments.

Strong knowledge of domain controllers, replication, DNS, Group Policy, authentication flows, and disaster recovery design for AD.

Practical experience implementing Microsoft security controls such as EPA, LDAP signing, channel binding, Kerberos hardening, SMB signing, and privileged account protections.

Experience with Active Directory Certificate Services, Active Directory Web Services, Windows Server hardening, and identity‑related remediation programs.

Ability to analyze and remediate privilege escalation paths, insecure account settings, and policy‑based configuration weaknesses.

Proficiency with PowerShell for audit, remediation, automation, and operational reporting.

Experience planning and executing infrastructure upgrades, domain controller replacement, and controlled production changes.