Active Directory is one of the main components in enterprise networks for user authentication and access management systems. This acts as a system that contains and controls network resources such as user accounts and security settings for an enterprise environment.
Active Directory is responsible for important security functions within enterprise networks today. It determines which users are permitted to access certain resources, provides access to security certificates, and enforces security policies on all connected devices and systems. Active Directory is the trusted mechanism that organizations use to ensure consistent security procedures are applied to protect sensitive data from unauthorized access.
In this blog, we will read about what Active Directory security is, how they are attacked by threat actors, and what organizations can do to mitigate these attacks. In this blog, we will focus on technical solutions and various security controls to protect the Active Directory infrastructure.
What is Active Directory Security?
Active Directory security is a series of measures to avoid a compromise of the directory service infrastructure. The system operates through domain controllers, which are servers that respond to security authentication requests from within a Windows Server network.
Why is Active Directory Security Important?
An essential element of enterprise defense comes from Active Directory security, as it controls access to network resources and sensitive data. Active Directory is the entry point for most corporate networks, and when a security breach occurs, attackers can navigate the network and access systems they should not. Active Directory compromises pose substantial operational risks to organizations, leading to data theft, system downtime, and regulatory compliance violations.
Multiple entry attack points arise from Active Directory configurations that contain security flaws. The presence of weak passwords, misconfigured permissions, and unpatched vulnerabilities provides potential access points for exploitation. After initial access is gained, attackers take advantage of trust relationships between the different domains to ultimately gain access to their final target domain. Domain Controller hacks are most damaging since these servers hold the authentication information of every domain user.
AD attacks have long recovery times. Re-establishing secure configurations needs extensive audits of user permissions, trust relationships, and Group Policy settings. Business functions are hampered as systems are checked for security and restored.
Key Components of Active Directory Security
Multiple components are connected to each other to secure the Active Directory. Authentication protocols such as Kerberos and NTLM check whether a user is who they say they are before they are allowed access to resources. It allows the use of encrypted tickets and challenge-response mechanisms to provide credential protection across the network.
Access control mechanisms specify what resources are accessible to users. Access Control Lists (ACLs) grant permissions to security principals, which are user accounts or security groups (collections of user accounts). These permissions are used to permit operations on directory objects such as read, write, or modify.
Domain security policies enforce controls that are standardized throughout their domains. Password policies enforce rules around things like password complexity, password age, and password reuse. To guard against brute force attacks, where malicious actors may try to guess and brute force their way past security measures, account lockout policies ensure that login attempts are only successful when used appropriately.
Common Threats To Active Directory Security
Active Directory is the central point for authentication and access control within a network. It is a chief target of multiple security threats. Attackers exploit Active Directory elements by employing a set of techniques to gain unauthorized access to or control over domain resources.
1. Account-Based Attacks
Password spraying and brute force attempts against user accounts are a common pursuit of threat actors. These account or password attacks target using widespread passwords against numerous accounts or test multiple passwords against specific accounts. Attackers using automated tools can attempt tons of password combinations, skipping account lockouts. User accounts are often among the first entry points, especially those with high-level administrative access.
2. Credential Theft
Using various tools, attackers extract credentials from the memory. Attackers are known to steal password hashes and even Kerberos tickets that are stored in LSASS process memory. Credential dumping tools extract these authentication materials from Domain Controllers or workstations directly. If attackers have valid credentials, they can often impersonate a legitimate user and bypass normal authentication controls.
3. Directory Service Exploitation
The flaws in Active Directory protocols and services introduce attack opportunities. LDAP misconfigurations permit plain connections, thus exposing directory queries for manipulation. Both DNS zone transfer settings and dynamic update configurations create vulnerabilities when they are not properly secured. These service-level issues are then used by attackers to gain knowledge of domain architecture and assets.
4. Replication Attacks
Domain Controller replication processes face specific threats. The DCSync attacks read password data over replication protocols. If attackers gain access to replication traffic, they can modify that data as it flows from one Domain Controller to another. When replication fails, it reveals data inconsistencies, creating open security gaps in domain-wide policy enforcement.
How Do Active Directory Attacks Work?
Domain compromise is achieved through different types of active directory attack techniques. These approaches attack different pieces of the authentication and authorization system, and often, a combination of approaches is used to get complete access to the network. Knowledge of these attack patterns enables organizations to put in place strong defense actions.
Privilege Escalation Techniques
Privilege escalation is a technique attackers use to obtain higher-level access to Active Directory environments (from a basic level). Initially, it involves the exploitation of common accounts of normal users using weak passwords or effective phishing attacks. Advanced methods enable attackers to overcome the misconfigured service account running with the domain admin privileges.
Kerberoasting Attacks
Kerberoasting is aimed at service accounts in AD. It operates by making TGS ticket requests for services running under domain accounts. In these tickets, the hashes of the service account password are presented in the encrypted form. Attackers pull these hashes offline to try to crack passwords. This method is particularly harmful against service accounts with weak passwords as they often hold administrative privileges.
Pass-the-Hash and Pass-the-Ticket attacks
These attacks work with previously captured sets of credentials and reusing them. In pass-the-hash attacks, attackers steal NTLM password hashes from one machine and use them to authenticate on other machines. Another approach is the pass-the-ticket attack which is based on the same principles but targets compromised Kerberos tickets instead of hashes. Either way, these are both lateral movement techniques used on the network without needing the actual password.
Golden and Silver Ticket Exploitation
Golden ticket attacks forge Kerberos tickets using the domain’s highest privileged account (KRBTGT). Once attackers have the KRBTGT hash, they can create tickets for any user or service in the domain. They allow bypassing of normal security controls, and they persist even when passwords are changed.
Instead of the domain-wide KRBTGT account, silver ticket attacks are performed against specific service accounts. Once the attacker has the hash of a service account, they can create forged service tickets for that service. Those tickets allow them to access a limited number of services but are less comprehensive than golden tickets.
Domain Replication Attacks
DCSync is a compromise that uses Directory Replication Service Remote Protocol (MS-DRSR) to obtain password data from domain controllers. It extracts password hashes for all password-based accounts in the domain if the attacker has replication rights.
DCShadow attacks involve simulating DC behavior by registering specific RPC servers and creating necessary directory objects to inject malicious changes that replicate through legitimate replication channels.
Active Directory Hardening Techniques
Technical controls and configurations can enhance organizations’ Active Directory security. These techniques include the hardening of essential elements of the directory infrastructure to avoid a larger attack surface and to prevent impact from commonly used exploitation techniques.
1. Domain Controller Hardening
Domain Controllers are the backbone of the AD network, and therefore, they have to be protected by a multilayered security approach. That means that physical security controls should prevent anyone from accessing the physical server hardware, and OS hardening removes unnecessary functionality and services that could be an entry point of attack. Security updates may need to be carried out on Windows Server components to fix known vulnerabilities and ensure an exploit does not take place.
2. LDAP Security Configuration
Security of Lightweight Directory Access Protocol (LDAP) regarding directory queries and modifications requires special monitoring. To mitigate risks and avoid directory traffic being altered while being transmitted, organizations need to turn on LDAP signing.
Configuring channel binding implementation to link LDAP connections to specific TLS channels thereby making connection hijacking impossible. These settings are enforced with Group Policy deployed across the domain, which requires LDAP server signing, client signing, and channel binding, and it denies simple binding over non-SSL and non-TLS connections.
3. DNS Security Implementation
DNS security is one of the most important aspects of Active Directory protection because name resolution services are essential to core directory functions. By preventing unauthorized updates of DNS records that could redirect traffic, secure dynamic updates help. Make sure DNS request origin integrity is authenticated by DNSSEC validation (to prevent spoofing).
4. Authentication Protocol Security
Authentication security is about the process of verifying credentials, and it needs to be carefully configured. Special care is to be taken for Kerberos settings, which should be prepared to enable AES encryption support but disable RC4 as an encryption method. Organizations should define appropriate maximum ticket lifetimes and adopt a password change notification system. NTLM security also deserves the same level of scrutiny, with settings that disable obsolete LM and NTLMv1 protocols while enforcing NTLMv2 and session security.
5. Administrative Access Control
Extensive controls are needed for administrative access to prevent abuse of privileges in the directory. Time-bound administrative access and just-in-time privilege elevation should be enforced through privileged access management systems. Organizations need a separate administrative account for daily tasks and another for privileged operations. Membership in the protected user’s security group applies further protections to privileged accounts, and role-based access control enables fine-grained assignment of permissions tailored to the specific job function.
Best Practices for Active Directory Security
In this section, we will discuss common AD security best practices to prevent common attacks against it.
1. Secure Administrative Practices
To avoid threats from administrative accounts, they need to be tightly controlled operationally. Dedicated administrative workstations for directory management need to be incorporated into organizations. It requires strong security controls such as application whitelisting and limited access to the internet where the workstations exist. All administrative actions should be logged through a Privileged Access Management (PAM) system that captures administrative actions taken from the computer and includes approval workflows for sensitive actions.
2. Password Policy Implementation
Password policies set the groundwork for domain account security. Organizations should set complexity requirements with a minimum of 16 characters, various characters, and an expiration period for passwords. To guard against brute force attacks, accounts should be locked out for a defined period of time after a limited number of failed login attempts. Password policies need to be periodically assessed to ensure that they are consistent with contemporary security practices and threat scenarios.
3. Group Policy Security
Security settings are controlled via group policy configuration over systems joined to a domain. Organizations should apply baseline security settings to restrain unused services and restrict user rights assignments. Changes to group policy objects must also have version control and a change management process to keep track of the changes. Verify that group policy processing occurs regularly so that policies are applied as intended to all systems. Auditing group policy settings to check for misconfiguration or conflicting policies can be a burden for security teams.
4. Service Account Management
Service accounts are in dire need of uniquely tailored security controls in order to prevent creational abuse. Every service or application must have its own service account provided by an organization. The accounts need long, complex passwords that are difficult to guess, unique for each account, and then changed on a schedule that organizations define. Audits on a regular basis to identify and delete either unused service accounts or excess permissions.
5. Regular Security Assessment
Active Directory health is maintained by systematic evaluation of security controls performed in the form of security assessments. Privilege audits are another important concept that organizations must execute from time to time in order to identify excessive permissions and eliminate those that are not needed. Security measures or standards that have been approved by baseline can be verified by conducting directory configuration reviews. The assessment report must have remediated plans with timelines to close security gaps.
Challenges For Active Directory Security
There are significant challenges to implementing AD security. These difficulties arise from architectural constraints, operational demands, and enterprise directory service system complexity. Let’s discuss a few of them.
1. Legacy Authentication Protocols
Legacy systems open security loopholes in the organization due to the use of outdated authentication methods. NTLM authentication is still required by many legacy applications, so organizations have no choice but to enable this insecure protocol.
2. Complex Permission Hierarchies
As Active Directory environments grow, AD permission structures become more complex and daunting. Nested group memberships eliminate clarity. Object permissions drip-feed over time through different admin tasks. Thus, ACL handling ends up being a complicated affair, especially when permissions are strewn across numerous organization systems and domains. It becomes difficult for security teams to keep track of clear permission boundaries and revoke access privileges that are no longer required.
3. Trust Relationship Management
Trust relations between forests, as well as between different domains in the same forest, are a complicated matter, especially when it comes to security management. External trusts open up avenues of attack to which security teams must stay vigilant. Organizations find it difficult to maintain accurate documentation of these trust relationships and verify security settings.
4. Service Account Proliferation
Service accounts are created as organizations launch new apps and services. Account safety needs to be managed constantly, with out-of-date passwords updated as time passes. Changing passwords creates problems with service dependencies, resulting in static credentials that break security policies. Many applications request unnecessary permissions for service accounts, further increasing attack surfaces. It is challenging for organizations to track how service accounts are used and clean up old accounts.
5. Privileged Access Misconfigurations
It is quite difficult to implement administrative access control. Emergency access procedures are typically implemented outside of normal security controls, which creates gaps in security. And temporary privilege assignments do not expire. Without proper implementation of time-bound access controls, organizations cannot have an accurate inventory of their privileged users.
Active Directory Security with SentinelOne
SentinelOne adds specialized Active Directory monitoring and protection capabilities. The platform works with directory services to detect and react to attacks against Active Directory infrastructure.
Real-Time Directory Monitoring
SentinelOne agents are deployed to monitor Active Directory events and activities. It monitors authentication attempts, changes to permissions, and updates to the directory down to the second through these agents. It maintains extensive logs relating to administrative actions and security-relevant events within the directory hierarchy.
Identity Protection Features
SentinelOne provides controls over directory identity protection. Using historical credential usage patterns, SentinelOne is able to identify potential credential compromises. It logs attempts to gain more privileges and unauthorized access to system administration functions. These offer automated responses that can include responding to suspicious authentication events and unusual account activity.
Automated Response Actions
SentinelOne automatically responds when threats target the Active Directory. Among those responses are blocking suspicious authentication attempts and quarantining compromised devices. Compromised accounts can be shut down, and unauthorized access rights can be revoked automatically on the platform. Configurable policies determine response actions while ensuring the availability of directory services.
Security Integration
The platform seamlessly connects with existing directory-based security tools and controls. Using some extra security checks, SentinelOne provides a way of Group Policy enforcement. It complements Windows built-in logging with detailed security telemetry. It has integration features that allow for central management of directory security using the SentinelOne console.
Conclusion
Active Directory security demands a comprehensive approach that combines technical controls, operational practices, and continuous monitoring. Organizations face evolving threats that target directory services through sophisticated attack techniques and exploit various system vulnerabilities. Understanding these threats and implementing proper security measures helps protect critical authentication and access control systems.
Security best practices lay a foundation for protecting Active Directory environments. Conducting regular security assessments to discover possible vulnerabilities along with validating the effectiveness of the associated controls. Administrative access should be managed through specific systems and written processes, but service accounts need continual maintenance to avoid security holes. The Group Policy is an excellent way to enforce security standards to all domain-joined systems, adding several layers of protection to prevent unauthorized access and system compromise.
Modern security solutions such as SentinelOne provide additional and more sophisticated protection, such as monitoring and automated remediation designed specifically for Active Directory. Such tools offer additional visibility into what is happening within your directories while speeding up threat detection and response.
FAQs
1. What is AD Security?
Active Directory Security is a set of measures and controls that secure the Active Directory service infrastructure used for network authentication and access. The protection features incorporate solutions to secure domain controllers, secure authentication protocols, and control access to resources in the enterprise environment.
2. Why is AD Security essential?
Active Directory security acts as the foundation of enterprise network protection, managing resource access and authenticating users with true identity. Successful compromise of Active Directory possibly means a full network compromise, data theft, and only a matter of time until all services/systems become disrupted, affecting business continuity.
3. How do we detect and mitigate AD security breaches?
Breaches are detected by continuous monitoring of authentication events, directories, and account activities. To mitigate the breach, steps should be followed, such as isolating systems from the network that have been compromised, revoking access to accounts, resetting credentials, etc.
4. How do you respond to an Active Directory compromise?
If Active Directory was compromised, then any particular system and domain controller would need to be isolated immediately. Remediate KRBTGT accounts, check directory backups, confirm all privileged account credentials in organizations, and closely monitor remaining systems.
5. What are common Active Directory misconfigurations?
Some misconfigurations include overly permissive privilege access rights, weak passwords on service accounts, unnecessary trust relations between domains, or disabled security measures. Security gaps tend to be the result of the default configurations, which are something that attackers are able to exploit.
6. What is the Active Directory Security Checklist?
Security checklist includes security assessments, access control securities, Group Policy securities, domain controller securities, and many more. It is the responsibility of organizations to reinforce authentication protocols, track changes to directory services, and keep security patches up to date.
7. How can ransomware attacks on Active Directory be prevented?
Measures to prevent ransomware attacks include the implementation of secure authentication protocols, limiting administrative access, keeping up-to-date backups, and monitoring your networks for suspicious happenings. It is necessary for organizations to secure domain controllers and enforce network segmentation to reduce the attack spread.