What is Active Directory?
Microsoft’s Active Directory (AD) is one of the most widely used authentication and authorisation systems in enterprise IT networks. Due to its pivotal role in managing access to systems, services and sensitive data, AD has become a prime target for cybercriminals. This article summarises key insights and recommendations from guidance authored by leading cyber security agencies, including ASD, CISA, NSA, CCCS, NCSC-NZ and NCSC-UK, outlining common attack techniques used against AD and strategies to mitigate these threats.
Active Directory: example use case
A common use of AD is in managing employee access to internal systems and resources.
For instance, in a mid-sized financial services company, AD is used to centralise and streamline user management. When a new employee joins, their details are entered into AD and the system automatically assigns them permissions based on their role. This includes access to specific applications like the company’s accounting software, shared drives with client files and email systems. AD handles user authentication, ensuring that only authorised employees can log in and access these resources.
Additionally, AD can enforce security policies across the organisation, such as requiring employees to change their passwords every 90 days or enforcing multi-factor authentication (MFA) for more sensitive areas of the network. If an employee is promoted or changes departments, AD can adjust their access privileges accordingly. Similarly, when someone leaves the company, their AD account is quickly deactivated, immediately cutting off access to all internal systems.
By using AD, the company reduces the administrative burden on IT staff, enhances security and ensures that each employee has appropriate, role-based access to the tools they need to do their job effectively.
Why Active Directory is Targeted by Cyber Attackers
AD’s powerful role in authentication makes it a valuable asset for cyber attackers. When compromised, malicious actors gain privileged access to an organisation’s entire network, allowing them to control critical systems such as email servers and business applications. Additionally, attackers can extend their access to cloud services via Microsoft Entra ID, heightening the risk of long-term persistence and disruption.
AD’s complexity, permissive default settings and support for legacy protocols create numerous security gaps that malicious actors frequently exploit. The intricate relationships between users, systems and configurations can be overlooked by organisations, making it easier for attackers to exploit misconfigurations, escalate privileges and gain complete control.
Common Attack Techniques
- Weak Default Settings: AD’s default configurations can provide broad permissions, allowing users to inadvertently expose sensitive information.
- Legacy Protocols: Outdated protocols still supported by AD can offer easier avenues for exploitation.
- Privilege Escalation: Attackers often escalate privileges by exploiting hidden relationships between users and systems, gaining full administrative control.
- Pass-the-Hash Attacks: Attackers can capture password hashes and use them to authenticate without needing the plaintext password.
How to Protect Active Directory
Organisations are encouraged to implement the following measures to strengthen their AD security:
- Enforce Strong Authentication Policies: Require multi-factor authentication (MFA) for privileged accounts and enforce complex password policies.
- Limit Administrative Privileges: Restrict access to administrative rights and monitor the creation of new privileged accounts.
- Regular Auditing and Monitoring: Regularly audit AD configurations, permissions, and logs for signs of unusual activity or privilege escalation.
- Patch Management: Ensure that systems are up to date with security patches to mitigate vulnerabilities in AD and associated services.
- Network Segmentation: Isolate AD servers from other critical systems to limit lateral movement in the event of a breach.
The aforementioned guidance provides detailed technical information on common attack techniques and ways to protect your organisation’s assets.
Many demands are already placed on internal IT teams for day-to-day business operations, Cyber Collab can support your IT team with enhancing, maintaining and uplifting their work. We can offer a Cyber Health Check and perform penetration tests to help identify areas which need more robust protection. Further, our Virtual CISO service will identify, develop and implement policies and procedures that create, maintain and enhance your business’ positive cyber security posture.
How to Detect and Respond to a Potential Active Directory Compromise
Organisations should monitor AD environments for signs of compromise, such as:
- Unusual Logins or Failed Authentication Attempts: Indications of brute force attacks or unauthorised access.
- Unauthorised Privilege Changes: Unexpected alterations to group memberships or administrative permissions.
- Persistence Techniques: Attackers may establish persistence by exploiting weaknesses to maintain access, even after remediation efforts.
If a compromise is suspected, isolate the affected systems, reset credentials and conduct a full investigation to understand the scope of the breach. In severe cases, organisations may need to rebuild the entire AD environment to evict sophisticated attackers. Again, the guidance provides detailed suggestions for responding to suspected compromises.
Cyber Collab’s Incident Response service supports organisations detect, contain and remedy compromises, getting businesses back up and running with the peace of mind that their assets and data are no longer affected.
Reach out to Cyber Collab today to improve your organisation’s Active Directory security, by reducing the likelihood of a compromise and ensuring a more resilient network infrastructure.