A practical approach to auditing Active Directory access control lists

Active Directory access control lists are often treated as a static export, reviewed once and filed away. Yet object permissions determine who can alter users, reset passwords, create privileged groups or change security policy. A useful audit tests effective access rather than merely identifying unfamiliar entries in an ACL.

Australian organisations commonly operate across Sydney, Melbourne and Brisbane, with hybrid staff and cloud workloads supported by on-premises directories. Synchronisation with Microsoft Entra ID can preserve local permissions after migration, while delegated helpdesks may retain reset rights. Auditing only the cloud portal can therefore miss meaningful privilege paths.

A defensible review combines read-only evidence, controlled validation and a documented remediation cycle. The result should identify exposed accounts, support privacy obligations under the Privacy Act 1988 and provide evidence aligned with the Australian Signals Directorate's Essential Eight, especially its requirements for standard access and privileged access.

Establish the audit scope

Define the directories, forests and business-critical groups in scope, including Tier 0, service, backup and departmental accounts. Identify change windows and nominate business owners who can validate permissions. Capture a point-in-time baseline of objects, group membership and delegation so later changes remain attributable.

Prioritise paths to domain administration, password resets, computer objects, Group Policy and backup systems. Record which systems will supply evidence and who performs the review. For Australian financial institutions, include relevant APRA CPS 230 operational-risk expectations; for government and healthcare clients, align samples with sector-specific oversight and retention requirements.

Collect and normalise permission evidence

Export ACLs from a domain controller using Active Directory PowerShell cmdlets, such as Get-Acl 'AD:\CN=Accounts,DC=example,DC=com', and store the results in a restricted workspace. Preserve the security descriptor, owner, access rules, inheritance flags and SDDL. These fields show how permissions apply and help distinguish direct grants from inherited access.

Supplement the export with LDAP group data, nested-group calculations, delegation configuration, SID history and privileged-identity inventory. Normalise unresolved SIDs rather than discarding them. Review SACLs only when audit policy requires them, and avoid creating noisy audit GUIDs during a read-only exercise.

Test effective access and privilege paths

Translate ACL entries into effective rights for users, computers and services. A harmless-looking member grant may become domain-wide control through group nesting or SID history. Test whether each account can enumerate privileged objects, change a password, add a member to a protected group, rewrite a DACL or create another privileged account.

Use a dedicated test identity with no shared credentials, and obtain approval before any write validation. Capture before-and-after evidence, then revert each change in the same window. Do not rely on administrative tools that show only the rights visible to the auditing administrator.

Rank confirmed paths by impact and likelihood, flagging broad principals such as Everyone or Authenticated Users, unapproved delegation and access to sensitive groups. If a Sydney operations team can modify the group used by Melbourne administrators, document the cross-site dependency rather than treating it as two separate findings.

Validate identity and administrative safeguards

Check whether the people behind those paths are still authorised. Remove leavers promptly, review dormant accounts and scrutinise service identities with interactive logon rights. Enforce phishing-resistant multifactor authentication for privileged roles, separate Tier 0 administration from ordinary support, and use just-in-time elevation where the platform supports it.

Identity threats extend beyond directory configuration: look-alike domains can help attackers solicit legitimate credentials, so automated domain alerts provide a useful control alongside MFA and user training. Forward domain-controller changes, sensitive group membership changes and unexplained ACL edits to the SIEM.

Remediate, monitor and prove improvement

Turn findings into a risk-ranked backlog. Replace direct user grants with role-based groups, remove redundant allows, break unsafe nesting and move elevated work to separate privileged access workstations. Require named owners to approve exceptions, with an expiry date and compensating control. Back up affected objects and retain rollback instructions before changing production permissions.

Retest the paths after remediation and retain command output, approvals and closure evidence. Where customers require assurance over access governance, a SOC 2 readiness assessment can connect directory-control testing to wider evidence requirements. Review local delegation practices in each Australian office so a helpdesk workflow in Brisbane cannot inherit unintended Melbourne support rights.

Schedule recurring reviews and trigger event-driven checks after role changes, acquisitions and migrations. Map exceptions to Essential Eight controls, Office of the Australian Information Commissioner privacy expectations and, where relevant, APRA requirements. A monthly dashboard should show overdue access reviews, unresolved high-risk paths and the age of each accepted exception.

The practical outcome is a repeatable control cycle: inventory, validate, remediate, retest and monitor. Each stage should leave evidence that an Australian board, regulator or customer can follow without reconstructing the original investigation.

Contact Infoziant Security for a scoped Active Directory access review, supported by its 24/7 SIEM monitoring and threat intelligence services. Its free VAPT reports and trial-based engagement offer a practical starting point for teams that want to benchmark exposure before a full remediation programme.