Best Practices for Securing an Active Directory AccountActive Directory (AD) is the backbone of identity and access management in many organizations. A compromised AD account can lead to unauthorized access, lateral movement, and full domain compromise. This article outlines practical, prioritized best practices to secure Active Directory accounts — from user hygiene to privileged account management, monitoring, and incident response.
1. Understand account types and attack surfaces
AD contains several account types, each with different risk profiles:
- User accounts — everyday employees, contractors, service accounts used by applications.
- Privileged accounts — Domain Admins, Enterprise Admins, schema admins, and other high‑privilege groups.
- Service accounts — managed, group Managed Service Accounts (gMSA), and traditional service accounts used by applications and services.
- Computer accounts — AD objects representing devices; attackers can abuse these for persistence.
Map these accounts and their privileges to understand what an attacker would target.
2. Enforce strong authentication
- Use Multi‑Factor Authentication (MFA) for all privileged access and, where feasible, for user accounts — especially remote access and administrative portals.
- Enforce strong password policies: minimum length, complexity, and password history. Prefer long passphrases over complex short passwords.
- Implement Azure AD Password Protection or on‑premises banned password lists to block common or predictable passwords.
- Use smartcards or certificate‑based authentication for highly privileged accounts where practical.
3. Harden privileged accounts and reduce standing privileges
- Apply the principle of least privilege: grant only the rights necessary for each role.
- Remove users from privileged groups and provide temporary elevated access via Just‑In‑Time (JIT) solutions (e.g., Microsoft PAM/JIT, third‑party vaults).
- Separate admin accounts from daily use accounts: require dedicated admin logon accounts that are not used for email or web browsing.
- Implement tiered administration (Tier 0, 1, 2) to isolate high‑impact systems and administrative paths.
- Use Privileged Access Workstations (PAWs) for sensitive administrative tasks.
4. Secure and manage service accounts
- Prefer Managed Service Accounts (MSA/gMSA) for services — they remove the need for manual password management.
- Where traditional service accounts are necessary, enforce strong, unique passwords and schedule regular rotation.
- Restrict service account delegation and logon restrictions (e.g., limit which hosts an account can log on to) via logonWorkstation and service configuration.
- Avoid granting service accounts unnecessary domain‑wide privileges.
5. Implement robust monitoring and logging
- Enable and centralize Windows event logging (Security, Sysmon where applicable) and forward logs to a SIEM for correlation and alerting.
- Monitor for high‑risk events: multiple failed authentications, unusual logon times, logons from new or foreign workstations, token theft indicators (e.g., Pass the Ticket patterns), and changes to privileged groups.
- Audit changes to sensitive AD objects: group membership changes, modifications to schema, domain controllers, and password policy changes.
- Retain logs for a sufficient period to support investigations (commonly 1 year for security‑relevant logs, adjusted to regulatory needs).
6. Protect domain controllers
- Harden domain controllers: minimal software, dedicated networks, and strict firewall rules limiting management traffic.
- Disable unnecessary services and block Internet access from domain controllers.
- Ensure regular patching and use secure boot, HVCI, and other platform protections where supported.
- Limit which accounts can log on locally or via RDP to domain controllers; use dedicated admin workstations instead.
7. Implement effective group policy and delegation controls
- Use Group Policy Objects (GPOs) to enforce security baseline settings (account lockout, local admin configurations, audit policies, SMB restrictions).
- Restrict who can create and link GPOs; audit GPO changes.
- Minimize use of domain local and built‑in privileged groups; create well‑scoped groups with carefully controlled membership.
- Regularly review delegated permissions (ACLs) on AD objects — remove stale or overly broad permissions.
8. Protect Kerberos and credential material
- Configure Kerberos policy settings to reduce ticket lifetimes for sensitive accounts.
- Enable AES encryption types and disable weak ciphers where possible.
- Use Windows Defender Credential Guard on endpoints to protect NTLM/LSA secrets and Kerberos tickets from extraction.
- Monitor for suspicious ticket activity and abnormal Service Principal Name (SPN) modifications used for Kerberoasting.
9. Secure remote access and external authentication paths
- Require VPNs or secure gateways with MFA for remote access to sensitive systems.
- Disable legacy protocols (NTLM, SMBv1, insecure LDAP) and prefer LDAPS or LDAP over TLS for directory replication and queries.
- Review and secure federation trusts, B2B/B2C integrations, and any external identity providers.
10. Regularly review, clean up, and harden the environment
- Perform periodic account reviews to disable or remove inactive accounts, orphaned service accounts, and stale privileged memberships.
- Enforce cleanup of disabled accounts older than policy thresholds; keep a documented approval process for account reactivation.
- Implement automated lifecycle processes (provisioning/deprovisioning) tied to HR systems to reduce orphaned access.
11. Use automation and secure secrets management
- Store credentials and secrets in a centralized vault (e.g., Azure Key Vault, HashiCorp Vault) with controlled access and audit trails.
- Automate account provisioning and deprovisioning with role‑based access control (RBAC) to reduce human error.
- Integrate PAM/vault solutions for issuance of temporary credentials and rotation of service account secrets.
12. Plan for incident detection and response
- Maintain an AD‑aware incident response plan that includes steps for containment, credential resets, forensic evidence preservation, and domain recovery.
- Practice tabletop exercises and runbooks for common breach scenarios (compromised admin, DC compromise, Kerberos abuse).
- Prestage clean admin accounts and recovery accounts stored offline to recover AD when domain controllers are compromised.
13. Education, policy, and governance
- Train administrators on AD attack techniques (Pass‑the‑Hash, Pass‑the‑Ticket, DCSync, Golden Ticket) and defense techniques.
- Document and enforce account management policies: password rules, privileged access workflows, acceptable use, and monitoring expectations.
- Conduct regular security assessments and penetration tests that include AD attack paths.
14. Leverage modern identity platforms and Zero Trust principles
- Move toward a Zero Trust model: verify explicitly, use least privilege, and assume breach.
- Where possible, integrate with cloud identity platforms (Azure AD) for conditional access, strong MFA, and risk‑based sign‑in detection — while maintaining secure hybrid configurations.
- Employ adaptive access policies that consider device health, user risk, location, and sign‑in context.
Conclusion
Securing Active Directory accounts requires layered controls: strong authentication, minimized standing privileges, diligent monitoring, hardened infrastructure, automation of secret management, and practiced response plans. Prioritize protections for privileged accounts and domain controllers, apply least privilege, enforce MFA, and maintain continuous visibility. These measures reduce the likelihood of compromise and limit impact if attackers gain a foothold.
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