Query: SIEM correlation: defense impairment activity consistent with Group Policy Modification
Matching passage: T1484.001 Group Policy Modification. Tactics: defense impairment, privilege escalation. Description: Adversaries may modify Group Policy Objects (GPOs) to subvert the intended discretionary access controls for a domain, usually with the intention of escalating privileges on the domain. Group policy allows for centralized management of user and computer settings in Active Directory (AD). GPOs are containers for group policy settings made up of files stored within a predictable network path `\<DOMAIN>\SYSVOL\<DOMAIN>\Policies\`.(Citation: TechNet Group Policy Basics)(Citation: ADSecurity GPO Persistence 2016) Like other objects in AD, GPOs have access controls associated with them. By default all user accounts in the domain have permission to read GPOs. It is possible to delegate GPO access control permissions, e.g. write access, to specific users or groups in the domain. Malicious GPO modifications can be used to implement many other malicious behaviors such as [Scheduled Task/Job](https://attack.mitre.org/techniques/T1053), [Disable or Modify Tools](https://attack.mitre.org/techniques/T1685), [Ingress Tool Transfer](https://attack.mitre.org/techniques/T1105), [Create Account](https://attack.mitre.org/techniques/T1136), [Service Execution](https://attack.mitre.org/techniques/T1569/002), and more.(Citation: ADSecurity GPO Persistence 2016)(Citation: Wald0 Guide to GPOs)(Citation: Harmj0y Abusing GPO Permissions)(Citation: Mandiant M Trends 2016)(Citation: Microsoft Hacking Team Breach) Since GPOs can control so many user and machine settings in the AD environment, there are a great number of potential attacks that can stem from this GPO abuse.(Citation: Wald0 Guide to GPOs) For example, publicly available scripts such as <code>New-GPOImmediateTask</code> can be leveraged to automate the creation of a malicious [Scheduled Task/Job](https://attack.mitre.org/techniques/T1053) by modifying GPO settings, in this case modifying <code>&lt;GPO_PATH&gt;\Machine\Preferences\ScheduledTasks\ScheduledTasks.xml</code>.(Citation: Wald0 Guide to GPOs)(Citation: Harmj0y Abusing GPO P
Near-miss passage: T1484 Domain or Tenant Policy Modification. Tactics: defense impairment, privilege escalation. Description: Adversaries may modify the configuration settings of a domain or identity tenant to evade defenses and/or escalate privileges in centrally managed environments. Such services provide a centralized means of managing identity resources such as devices and accounts, and often include configuration settings that may apply between domains or tenants such as trust relationships, identity syncing, or identity federation. Modifications to domain or tenant settings may include altering domain Group Policy Objects (GPOs) in Microsoft Active Directory (AD) or changing trust settings for domains, including federation trusts relationships between domains or tenants. With sufficient permissions, adversaries can modify domain or tenant policy settings. Since configuration settings for these services apply to a large number of identity resources, there are a great number of potential attacks malicious outcomes that can stem from this abuse. Examples of such abuse include: * modifying GPOs to push a malicious [Scheduled Task](https://attack.mitre.org/techniques/T1053/005) to computers throughout the domain environment(Citation: ADSecurity GPO Persistence 2016)(Citation: Wald0 Guide to GPOs)(Citation: Harmj0y Abusing GPO Permissions) * modifying domain trusts to include an adversary-controlled domain, allowing adversaries to forge access tokens that will subsequently be accepted by victim domain resources(Citation: Microsoft - Customer Guidance on Recent Nation-State Cyber Attacks) * changing configuration settings within the AD environment to implement a [Rogue Domain Controller](https://attack.mitre.org/techniques/T1207). * adding new, adversary-controlled federated identity providers to identity tenants, allowing adversaries to authenticate as any user managed by the victim tenant (Citation: Okta Cross-Tenant Impersonation 2023) Adversaries may temporarily modify domain or tenant policy, carry out a malicious action(s), and then revert the change to remove suspicious indicators.