CTD-000127

Regular AD object with access to gMSA passwords

High
Active Directory
Credential Access
v12

Signature Identity

CTD-000127
Threat ID
12
Version
IOE
Indicator Type

Threat Description

A standalone Managed Service Account (sMSA) is a managed domain account designed to streamline security through automated password management, simplified Service Principal Name (SPN) management, and the capability to delegate management tasks to other administrators. A Group Managed Service Account (gMSA) extends the capabilities of an sMSA across multiple servers within a domain. It supports automated password and SPN management and allows sharing of passwords across multiple systems. When a gMSA is used as a service principal, the Windows operating system handles password management, eliminating administrators’ need for manual intervention.

Computers that utilize gMSAs request the current password from Active Directory to initiate services. The gMSAs can be configured to allow computer accounts to access the password. A potential security issue arises when a threat actor takes control of a computer hosting a service that uses a gMSA, or an account with the necessary permissions to request a gMSA password, thereby compromising the gMSA.

NOTE: Cayosoft Guardian defines privileged users in Active Directory as users with adminCount=1. By design Active Directory uses this attribute to protect members of administrative groups.

According to security best practices it is not recommended re-using admin accounts, instead these accounts must be de-provisioned. If an account has administrative permissions, it might also obtain access to other resources using these administrative permissions and keep this access even after it is removed from the administrative groups. Learn more about AdminSdHolder and SDProp – Microsoft Community Hub.

MITRE ATT&CK: Attack Tactics

Credential Access

D3FEND: Defend Tactics

Domain Account Monitoring

Remediation

To remove a security principal from the msDS-GroupMSAMembership (PrincipalsAllowedToRetrieveManagedPassword) attribute, use the Set-ADServiceAccount command. See: Attacking Active Directory Group Managed Service Accounts (GMSAs) – Active Directory Security (adsecurity.org)

Frequently Asked Questions

What does Regular AD object with access to gMSA passwords mean?

A regular Active Directory (AD) object, such as a user or group, that has been granted permission to retrieve the password of a Group Managed Service Account (gMSA), allowing it to access the gMSA's credentials without needing the actual password.

This scenario is rated high severity because an attacker can use the object's permissions to retrieve and use the gMSA's credentials, granting unauthorized access to domain resources and sensitive data. Specifically, this occurs when a regular AD object has been granted the 'Read' permission on the gMSA's password attribute (msDS-GroupManagedServiceAccountPassword), allowing it to obtain the password without needing the actual credentials.

Attackers exploit this vulnerability by using the object's permissions to obtain and utilize the gMSA's credentials, allowing them to access domain resources without needing the actual password. This can be done through various means, such as using the obtained password to authenticate to domain resources or using it to create new accounts with elevated privileges.

Cayosoft Guardian continuously monitors Active Directory for changes or anomalies indicating unauthorized access to gMSA credentials, flagging such issues as security concerns and alerting administrators. Specifically, it detects when a regular AD object has been granted the 'Read' permission on the gMSA's password attribute (msDS-GroupManagedServiceAccountPassword), which is not intended for standard AD objects.

Cayosoft Guardian provides visibility into these permissions, alerting administrators when they are misconfigured or exploited, enabling teams to quickly identify and address potential security issues before attackers can utilize them. This is achieved through continuous monitoring and anomaly detection, which provide real-time insights into Active Directory configurations and help administrators stay ahead of potential threats.

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Cayosoft Protector provides continuous monitoring and real-time alerts across your entire Microsoft Identity stack

Classification
Systems
Active Directory
Themes
Infrastructure
Attack Tactics
Credential Access
Defend Tactics
Domain Account Monitoring
Indicator Types
IOE
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