Identity and Access Management
Suspicious Active Directory Operations
Detection overview
Suspicious Active Directory (AD) Operations detection identifies unusual and potentially malicious activities within the Active Directory environment. These activities may include unauthorized modifications to AD objects, changes in group memberships, unusual login patterns, and other actions that deviate from normal behavior. Detecting these anomalies is crucial as they often indicate attempts to escalate privileges, create backdoors, or exfiltrate sensitive information.
Triggers
- Either a new or non-domain controller host successfully triggered an anomalous Active Directory replication request against a legitimate domain controller. This functionality is normally limited to usage by domain controllers and limited high-privilege service accounts.
Possible Root Causes
Malicious Detection
- Provided the malicious actor has the required permissions and connectivity to a domain controller, they can leverage the DRS RPC protocol to successfully execute the following attacks:
- DCSync: A malicious actor mimics a domain controller and targets a legitimate domain controller to invoke a Replication request (GetNCChanges) of the targeted AD Database containing hashed passwords.
- DCShadow: A malicious actor creates a rogue domain controller by targeting a legitimate domain controller to add itself to a group of hosts permitted to receive these requests (domain controllers). The attacker will then force replication, dumping the Active Directory database and hashed password to the rogue domain controller. The attacker then typically removes itself from the list of hosts permitted to receive the requests.
Benign Detection
- A new domain controller has been deployed and hasn’t had enough history to be identified as a domain controller.
Business Impact
- Specific Risk: Successful execution of either attack results in access to both usernames and hashed passwords of the targeted Active Directory infrastructure. An attacker can then perform offline attacks against the hashed passwords to escalate access.
- Impact: These attacks likely result in a full domain compromise due to malicious actor having access to privileged account hashed passwords which will either be cracked or used to authenticate (NTLM) to other services/hosts.
Steps to Verify
- Investigate the host involved in the alert, verify if the host is a true domain controller through either an internal CMDB or Active Query of Domain Controller hosts on your environment.
- Either the addition or removal of a domain controller on an environment is a rare event in comparison to other events within the environment and more specially within the RPC metadata stream.
- Usage of requests like GetNCChanges, ReplicaAdd, or UpdateRefs are explicit are specific to only domain controllers.
- If this host is a domain controller you should add it to the Domain Controllers Group, and apply a triage filter to exclude this host from generating a detection.
- Based on your environments configuration the replication requests should occur on a timely interval (default 15 minutes). In normal usage, you should see subsequent replication events. In malicious cases, these events will typically occur once, as there is no requirement for another replication of the database.
- Review logs for indications of either privileged accounts with the following:
- Privileged accounts using old/odd authentication types such as NTLM to new hosts and services.
- Privileged accounts invoking actions across multiple hosts on network within the RPC metadata stream
Suspicious Active Directory Operations
Possible root causes
Malicious Detection
- An attacker gaining unauthorized access and attempting to escalate privileges.
- Use of compromised credentials to manipulate AD objects.
- Execution of malicious scripts or tools to enumerate and exploit AD weaknesses.
- Insider threat involving a disgruntled employee making unauthorized changes.
Benign Detection
- Routine administrative tasks performed without prior notice or documentation.
- Misconfigurations or errors during legitimate AD management activities.
- Penetration testing or security assessments conducted by authorized personnel.
Suspicious Active Directory Operations
Example scenarios
Scenario 1: An attacker uses a compromised user account to gain access to the AD and attempts to modify group memberships to include their account in a privileged group. This detection is triggered by the unusual modification patterns and high volume of group change requests.
Scenario 2: A legitimate system administrator performs an AD schema update without following the change management process, leading to the detection of unusual AD operations. The activity is verified as authorized but misdocumented.
Suspicious Active Directory Operations
Business impact
If this detection indicates a genuine threat, the organization faces significant risks:
Privilege Escalation
Attackers gaining elevated privileges can control AD and compromise the entire network.
Data Breach
Unauthorized access to sensitive information stored within AD.
Operational Disruption
Changes to AD objects and policies can disrupt business operations.
Suspicious Active Directory Operations
Steps to investigate
Review AD Logs
- Check security logs for unusual login attempts, account creations, and group modifications.
- Look for patterns of failed logins followed by successful ones.
Correlate with User Activity
- Verify if the actions were performed by authorized personnel.
- Look for deviations from the user’s normal activity patterns.
Examine Tools and Scripts
- Check for the presence of known AD exploitation tools (e.g., BloodHound, Mimikatz).
- Review scripts and automated tasks that interact with AD.
Conduct a Threat Hunt
- Search for other indicators of compromise or malicious activity in the network.
- Verify if the detected changes are part of a scheduled security assessment or penetration test.
Suspicious Active Directory Operations
MITRE ATT&CK techniques covered
Suspicious Active Directory Operations
Related detections
FAQs
What are Suspicious Active Directory Operations?
Suspicious Active Directory Operations refer to unusual and potentially unauthorized activities within the AD environment that deviate from normal patterns and may indicate malicious intent.
How can I detect suspicious AD operations in my environment?
Look for unusual patterns in login attempts, AD object modifications, group membership changes, and high volumes of AD queries. Monitoring tools and detection systems can help identify these anomalies.
What are the common signs of suspicious AD operations?
Multiple failed login attempts followed by success, unauthorized changes to AD objects, unexpected group membership modifications, and creation of new user accounts without proper authorization.
Why are suspicious AD operations a significant threat?
They often indicate attempts to escalate privileges, create backdoors, or exfiltrate sensitive information, leading to potential data breaches and operational disruptions.
Can legitimate activities trigger suspicious AD operations detection?
Yes, routine administrative tasks, misconfigurations, or security assessments can trigger this detection. It's important to verify the context of the activity.
What steps should I take if I detect suspicious AD operations?
Investigate the source of the actions, verify if they are legitimate, and check for other signs of malicious activity. If necessary, take steps to secure compromised accounts and update AD policies.
How does Vectra AI detect suspicious AD operations?
Vectra AI uses advanced AI algorithms to analyze AD activity and identify patterns indicative of suspicious operations, correlating these with other suspicious behaviors.
What tools can help verify the presence of suspicious AD operations?
Tools like AD monitoring solutions, security information and event management (SIEM) systems, and specialized AD analysis tools can help identify suspicious operations.
What is the business impact of suspicious AD operations?
The primary risks are privilege escalation, data breaches, and operational disruptions, which can lead to significant damage to the organization.
How can I prevent suspicious AD operations?
Implement strict access controls, monitor AD activity, use strong passwords, and regularly audit user activity and permissions.