CTD-000056

AD domain allows unprivileged users to add computer accounts

High
Active Directory
Initial Access
v30

Signature Identity

CTD-000056
Threat ID
30
Version
IOE
Indicator Type

Threat Description

  1. By default, the ms-DS-MachineAccountQuota attribute is set to 10, which means that any user in Active Directory can create up to 10 computer accounts associated with them. The legitimate usage of this attribute is to allow users to have multiple devices on a network that belong to them that they can then manage. However, if a compromised user doesn’t have 10 actual devices associated with their account, an attacker can create an account for a non-existing device that will be an object in Active Directory. This fake computer account isn’t associated with a real device but can perform Active Directory authentication requests as if it were.
  2. Organizations should also consider setting the ms-DS-MachineAccountQuota attribute to 0 to make it more difficult for an attacker to leverage the attribute for attacks. Setting the attribute to 0 stops non-admin users from adding new devices to the domain, blocking the most effective method to carry out the attack’s first step and forcing threat actors to choose more complex methods to acquire a suitable resource.

MITRE ATT&CK: Attack Tactics

Initial Access

D3FEND: Defend Tactics

Application Configuration Hardening

Remediation

To modify Active Directory to allow more (or fewer) machine accounts on the domain, use the Adsiedit tool:

  1. Run Adsiedit.msc as an administrator of the domain.
  2. Expand the Domain NC node. This node contains an object that begins with “DC=” and reflects the correct domain name.
  3. Right-click this object.
  4. Select Properties.
  5. In the Select which properties to view box, select Both.
  6. In the Select a property to view box, select ms-DS-MachineAccountQuota.
  7. In the Edit Attribute box type 0.
  8. Select Set > OK.

Frequently Asked Questions

What does AD domain allows unprivileged users to add computer accounts mean?

In an Active Directory environment, the ms-DS-MachineAccountQuota attribute is set by default, allowing any user to create up to 10 computer accounts associated with them. This attribute can be exploited by attackers to create legitimate-looking computer accounts that can perform authentication requests.

This threat is rated high severity because an attacker can use the ms-DS-MachineAccountQuota attribute to create legitimate-looking computer accounts, which can then be used to perform authentication requests and gain unauthorized access to the domain. Specifically, this allows attackers to bypass security controls and move laterally within the network.

Attackers can exploit the ms-DS-MachineAccountQuota attribute by creating legitimate-looking computer accounts that can perform authentication requests, allowing them to gain unauthorized access to the domain and use it as a foothold for further attacks. This enables attackers to move laterally within the network, increasing their chances of successful exploitation.

Cayosoft Guardian continuously monitors the ms-DS-MachineAccountQuota attribute across the Active Directory environment and flags it as a security issue when set to a value greater than 0, alerting administrators to potential threats. This provides visibility into potential attack paths and enables swift response.

Cayosoft Guardian helps reduce the risk by alerting administrators to set the ms-DS-MachineAccountQuota attribute to 0, blocking non-admin users from adding new devices and limiting an attacker's ability to create legitimate-looking computer accounts. This supports investigation and response efforts by providing a clear audit trail of changes made to the attribute.

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Classification
Systems
Active Directory
Themes
Domain-wide Infrastructure
Attack Tactics
Initial Access
Defend Tactics
Application Configuration Hardening
Indicator Types
IOE
Related Threats
CTD-000139
Kerberos Constrained Delegation: krbtgt Risks
Critical
CTD-000122
Active Directory Schema Update Permission Risks
Critical