Trust Modification

What the technique is

Adversaries may add new domain trusts, modify the properties of existing domain trusts, or otherwise change the configuration of trust relationships between domains and tenants to evade defenses and/or elevate privileges.Trust details, such as whether or not user identities are federated, allow authentication and authorization properties to apply between domains or tenants for the purpose of accessing shared resources. These trust objects may include accounts, credentials, and other authentication material applied to servers, tokens, and domains. Manipulating these trusts may allow an adversary to escalate privileges and/or evade defenses by modifying settings to add objects which they control. For example, in Microsoft Active Directory (AD) environments, this may be used to forge SAML Tokens without the need to compromise the signing certificate to forge new credentials. Instead, an adversary can manipulate domain trusts to add their own signing certificate. An adversary may also convert an AD domain to a federated domain using Active Directory Federation Services (AD FS), which may enable malicious trust modifications such as altering the claim issuance rules to log in any valid set of credentials as a specified user. […]

What MITRE says you would watch

• AN1259

  Adversary modifies Active Directory domain trust settings via netdom, nltest, or PowerShell to add new domain trust or alter federation. Modifications occur in AD object attributes like trustDirection, trustType, trustAttributes, often paired with SeEnableDelegationPrivilege or certificate injection.

• AN1260

  Adversary adds federated identity provider (IdP) or modifies tenant domain authentication from Managed to Federated. Detected via API, PowerShell, or Admin Portal through federation events like Set domain authentication, Add federated identity provider, or Update-MsolFederatedDomain.