Sigma Rule Library

Powerview Add-DomainObjectAcl DCSync AD Extend Right

Backdooring domain object to grant the rights associated with DCSync to a regular user or machine account using Powerview\Add-DomainObjectAcl DCSync Extended Right cmdlet, will allow to re-obtain the pwd hashes of any user/computer

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Detection logic

selection

EventID: 5136
AttributeLDAPDisplayName: ntSecurityDescriptor
AttributeValue|contains:
  - 1131f6ad-9c07-11d1-f79f-00c04fc2dcd2
  - 1131f6aa-9c07-11d1-f79f-00c04fc2dcd2
  - 89e95b76-444d-4c62-991a-0facbeda640c

filter_main_dns_object_class

ObjectClass:
  - dnsNode
  - dnsZoneScope
  - dnsZone

Condition

selection and not 1 of filter_main_*

Raw YAML

title: Powerview Add-DomainObjectAcl DCSync AD Extend Right
id: 2c99737c-585d-4431-b61a-c911d86ff32f
status: test
description: Backdooring domain object to grant the rights associated with DCSync to a regular user or machine account using Powerview\Add-DomainObjectAcl DCSync Extended Right cmdlet, will allow to re-obtain the pwd hashes of any user/computer
references:
    - https://twitter.com/menasec1/status/1111556090137903104
    - https://www.specterops.io/assets/resources/an_ace_up_the_sleeve.pdf
author: Samir Bousseaden, Roberto Rodriguez @Cyb3rWard0g, oscd.community, Tim Shelton, Maxence Fossat
date: 2019-04-03
modified: 2022-08-16
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1098
logsource:
    product: windows
    service: security
    definition: 'Requirements: The "Audit Directory Service Changes" logging policy must be configured in order to receive events. Audit events are generated only for objects with configured system access control lists (SACLs). Audit events are generated only for objects with configured system access control lists (SACLs) and only when accessed in a manner that matches their SACL settings. This policy covers the following events ids - 5136, 5137, 5138, 5139, 5141. Note that the default policy does not cover User objects. For that a custom AuditRule need to be setup (See https://github.com/OTRF/Set-AuditRule)'
detection:
    selection:
        EventID: 5136
        AttributeLDAPDisplayName: 'ntSecurityDescriptor'
        AttributeValue|contains:
            - '1131f6ad-9c07-11d1-f79f-00c04fc2dcd2'
            - '1131f6aa-9c07-11d1-f79f-00c04fc2dcd2'
            - '89e95b76-444d-4c62-991a-0facbeda640c'
    filter_main_dns_object_class:
        ObjectClass:
            - 'dnsNode'
            - 'dnsZoneScope'
            - 'dnsZone'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - New Domain Controller computer account, check user SIDs within the value attribute of event 5136 and verify if it's a regular user or DC computer account.
level: high

False positives

  • New Domain Controller computer account, check user SIDs within the value attribute of event 5136 and verify if it's a regular user or DC computer account.

References

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