What is Active Directory? Understand and master this IT asset management solution
Present in most Windows environments, Active Directory plays a key role in controlling access and protecting data. A true pillar of computer security, it conditions the reliability of the entire information system.
Active Directory (AD) is a directory service developed by Microsoft to centralize identity and access management in environments Windows Server. Essential to cybersecurity For businesses, Active Directory allows users, groups, computers, and network resources to be centrally administered.
In this article, we look at:
- The definition of Active Directory and its objectives;
- Its architecture and its essential components;
- Its advantages in an organization;
- Best practices for securing AD;
- Its role in a global GRC approach.
Definition of Active Directory
Active Directory is a management service developed by Microsoft for Windows operating systems. In particular, it offers directory services (LDAP protocol support),authentication (Kerberos protocol), of name resolution (DNS protocol), etc.
It is an essential tool that allows centralize And oforganize information on the various elements of the network : user identity, computer accounts, groups, authentication information, etc.
The main goals of Active Directory are:
- Centralize the identity management (user accounts, machines, groups);
- Centralize access rights And the network resources ;
- Simplifying authentication ;
- Provide a structured and prioritized framework for the organization of the network infrastructure;
- Securing the network.
In summary, AD allows a company to have a” unique directory ” centralized for simplified management of a company's resources, in particular identities and computer equipment.
Good to know : kerberos, the authentication service, plays a key role in the Active Directory. It ensures the authentication of users as soon as they connect to their sessions. It also allows them to access resources according to their permissions.
What is the difference between Active Directory and Azure Active Directory?
Although they share a similar name, Active Directory (AD) and Azure Active Directory (Azure AD) meet different needs.
- Active Directory is designed for environments On-premise : it manages the users, groups, and resources of an internal Windows Server network.
- Azure Active Directory, now renowned Microsoft Entra ID, is a solution Cloud dedicated to the identity and access management for SaaS, Microsoft 365, or Azure applications.
The two solutions can coexist: hybrid AD/Azure AD integration allows you to manage both local access and that of cloud services, while strengthening the global security and compliance of the company.
Active Directory architecture and components
The key objects and elements of Active Directory
Active Directory stores and prioritizes information in the form of” objects ” (all network resources, such as user accounts, computers, groups, etc.).
These objects are classified into three main categories:
- Les users and user groups including their authorized services and rights;
- Les resources : workstation (printers, mobiles, etc.);
- Les services and applications : email (Exchange), Office 365, business applications, etc.
Each object represents a unique entity and has its own identification.
When the elements are configured, they thus make it easy to determine in detail all the resources of the computer system of an organization. In an Active Directory, it is thus possible to identify a number of resources ranging from a few hundred to several million.
How is Active Directory structured?
AD includes several logical and physical components that make it possible to secure corporate networks.
The logical components
Logical components refer to the administrative structure that is created, organized, and managed by IT professionals:
- Organizational unit (OU) : This is a container object used to prioritize Active Directory. OUs make it possible to structure objects within a domain (e.g. according to a geographic or functional organization) in order to clarify complex directories.
- Domains : a basic unit of AD combining a set of objects that share the directory database, a schema, and domain controllers.
- Forests : grouping of trees (and therefore domains) that share a common directory schema, global catalogs and a trust structure.
- Trees: includes several domains that have a common root domain (e.g. hr.example.com and sales.example.com).
The physical components
Physical components refer to the actual server infrastructure that hosts Active Directory.
Among these components, we find the domain controller (DC) which is the central server of an organization managing AD. Businesses generally have multiple domain controllers who each have a copy of the directory for all domains.
If changes are made to the directory on one of the domain controllers (e.g. adding a user), they are replicated (replication process) on each domain controller to ensure consistency across the network.
It is advisable to have at least two domain controllers to ensure the availability of the network in the event of a failure of one of the two.
The benefits of Active Directory for a business
Centralized data management
AD offers a central point of administration for users, groups, security policies... The fact of having a centralized platform to create, modify or delete users facilitates management and reduces the duplication of tasks.
Enhanced security
A centralized directory makes it possible to apply homogeneous security policies, to implement the Principle of least privilege and security features like themulti-factor authentication (MFA) and thesingle sign-on (SSO) that reduce password-related vulnerabilities.
These access controls as well as the group policies (GPO) define strict password management policies and restrict user access to certain files or applications based on their role in the business. Finally, AD's security features protect sensitive data from cyberattacks.
Good to know : In a Windows environment, group policies (GPOs) refer to a set of settings and rules that apply to users and computers in order to To control And ofhomogenize security policies and access restrictions via Active Directory. In particular, group strategies make it possible to: strengthen network security by imposing certain standards (e.g.: GDPR compliance, internal regulations, etc.).
Scalability
Whether for an SME or a large multi-site organization, Active Directory is able to adapt, thanks to its multi-domain, multi-forest structure and its replication process.
Improving the user experience
Generally, when an organization uses an Active Directory, employees use it on a daily basis without realizing it. They benefit from single authentication in the field, simplified management of their identity and more fluid access to resources. This decreases friction and support costs.
Simplified resource sharing
Sharing resources, such as printers or files, is simplified thanks to Active Directory. Administrators can manage these resources centrally and make them accessible to all users without the need to install additional software.
Faster troubleshooting
In general, AD allows you to protect yourself against failures and the loss of information by using the replication objects to the various domain controllers.
That said, when problems occur, AD allows you to diagnose more quickly thanks to its centralized system by providing detailed logs of user activities and system events.
Securing Active Directory: Essential Best Practices
Why is Active Directory security critical?
More than 90% of businesses in the world rely today on Active Directory to manage their identities and accesses. This central role makes it a preferred target for cyberattacks, including ransomware and privilege escalations.
A vulnerability or misconfiguration in AD can offer attackers complete access to the information system. Hence the importance of a Active Directory security reinforced and regular audits to detect any anomaly.
Thus, Active Directory integrates multiple security features, such as access control lists (ACLs) or encryption, to protect sensitive data and resources.
However, the use of these functions is not enough to guarantee complete and lasting security. To set up a secure domain controller and sustainable, it is essential to combine technical tools with rigorous governance. The effective protection of Active Directory therefore depends on the implementation of complementary measures and adapted strategies, in particular security audits regular.
Here are the best practices to adopt for strengthen the security of an Active Directory environment and anticipate risks.
Applying the principle of least privilege
The Principle of least privilege consists in giving each user account only the rights necessary for its function. Only authorized personnel should have administrative access to the AD.
Recommended actions:
- Minimize domain administrators;
- Use dedicated administration accounts (a standard account for office automation, an admin account for sensitive tasks);
- Deactivate or delete unused accounts;
- Prohibit administrative connections on user computers;
- Achieve a Active Directory audit regular accounts and privileges.
Secure domain administrator accounts
Cyberattackers primarily target administrator accounts associated with AD since these users have high privileges And a administrative control over an entire domain of a “forest”.
Recommended actions:
- Change the default name “administrator” to something more difficult for hackers to guess;
- Enforce a strong password policy and regular rotation;
- Implement themulti-factor authentication (MFA) for all privileged accounts.
Harden domain controllers
The hardening of domain controllers is essential to limit the attack surface.
Measures to be adopted:
- Systematically apply security updates;
- Deactivate non-essential services;
- Restrict remote and administrative accesses via ACLs (network access control list);
- Monitor changes to the registry and sensitive system files.
Monitor service accounts
Often overlooked, these accounts can represent a critical flaw if they are not properly managed.
Best practices:
- Use gMSAs (Group Managed Service Accounts) with automatic password rotation;
- Assign the minimum required permissions;
- Document their use;
- Monitor for any anomalous authentication.
What other Active Directory services are there?
Over the years, Microsoft has improved the Active Directory offer by supplementing it with numerous services:
- Active Directory Domain Service (AD DS — Active Directory Domain Services): It is the main directory service that is responsible for storing and managing users, systems, and resources within domains. AD DS processes authentication requests and access rights, serving as a starting point for most organizations.
- Active Directory lightweight directory service (AD LDS — Active Directory Lightweight Directory Services): This is a simplified version of AD that provides basic directory functions, while providing increased efficiency and maintaining security standards. It is ideal for small networks.
- Active Directory Federation Service (AD FS — Active Directory Federation Services): AD FS is a single sign-on (SSO) web service. It makes it easy to share access with partners or cloud applications across organization borders.
- Active Directory Certificate Service (AD CS — Active Directory Certificate Services): this service thus ensures the encryption and signing of files, as well as the issuance of digital certificates intended to authenticate users and machines.
- Active Directory Rights Management Service (AD RMS — Active Directory Rights Management Services): This service protects sensitive content by applying usage restrictions to documents or emails rather than to users. This limits the actions a user can perform on specific files or folders (e.g., copy, screenshot, print).
Active Directory: a pillar of a company's GRC strategy
Active Directory is at the heart of cybersecurity: it centralizes identity and access management. In other words: the person who controls AD controls everything.
By compromising a privileged account or domain controller, an attacker can, for example:
- Create or modify accounts;
- Deploy malicious GPOs;
- Deactivate security;
- Spreading ransomware throughout the IS.
That's why the securing the Active Directory Is a top priority for any cybersecurity team.
Active Directory should be treated as a strategic asset : its structure, security, governance and monitoring must be aligned with the requirements of risk, compliance and business continuity of the company.
A platform like Egerie helps businesses integrate Active Directory into their global GRC approach:
- Make a risk mapping associated with AD;
- Access to dynamic dashboards for real-time monitoring of these risks;
- Simulate incident scenarios to anticipate operational, regulatory or financial consequences;
- Ensuring regulatory compliance and facilitate audits;
- Facilitate strategic decision making thanks to clear, action-oriented reports...
By adopting a global approach — well-thought-out architecture, enhanced security, enhanced security, active surveillance, integration into the GRC cycle — Active Directory becomes a element of resiliency for the company.
Ask for a personalized demo to find out how to centralize your Active Directory risks into an integrated GRC approach.
FAQ: understanding and securing Active Directory
What is the difference between Active Directory and Azure Active Directory?
AD is a comprehensive directory service for on-premise Windows environments. Azure AD is an identity and access oriented cloud service for Microsoft 365 services, Azure, and other cloud applications. Their functionalities are not exactly the same, but they are complementary and can work at the same time.
What is the role of a domain controller?
A domain controller (DC) hosts the directory database for a domain, responds to authentication and directory requests, and participates in the replication of directory data.
What are Organizational Units (OU)?
OUs allow objects to be logically structured (by function, geographic location, service) and to apply GPOs. This makes it possible to avoid the multiplication of domains. They also make it possible to set up security controls and administrative organization specific to each department.
How does replication work in AD?
Directory data is stored on multiple domain controllers (DCs). When a change is made (e.g. user addition), it is propagated to the other DCs according to the replication process and only the changes are transmitted, which limits traffic.
What are the security risks associated with AD?
Among the risks: poorly managed privileges (too many admin users), poorly configured permissions, unconstrained delegation, lack of backup/restore, vulnerabilities in authentication protocols. It is therefore essential to do regular audits and to apply the best practices mentioned in the article.
