Az AD Connect - Hybrid Identity

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Basic Information

Integration between On-premises Active Directory (AD) and Azure AD is facilitated by Azure AD Connect, offering various methods that support Single Sign-on (SSO). Each method, while useful, presents potential security vulnerabilities that could be exploited to compromise cloud or on-premises environments:

• Pass-Through Authentication (PTA):
  • Possible compromise of the agent on the on-prem AD, allowing validation of user passwords for Azure connections (on-prem to Cloud).
  • Feasibility of registering a new agent to validate authentications in a new location (Cloud to on-prem).

Az - PTA - Pass-through Authentication

• Password Hash Sync (PHS):
  • Potential extraction of clear-text passwords of privileged users from the AD, including credentials of a high-privileged, auto-generated AzureAD user.

Az - PHS - Password Hash Sync

• Federation:
  • Theft of the private key used for SAML signing, enabling impersonation of on-prem and cloud identities.

Az - Federation

• Seamless SSO:
  • Theft of the AZUREADSSOACC user's password, used for signing Kerberos silver tickets, allowing impersonation of any cloud user.

Az - Seamless SSO

• Cloud Kerberos Trust:
  • Possibility of escalating from Global Admin to on-prem Domain Admin by manipulating AzureAD user usernames and SIDs and requesting TGTs from AzureAD.

Az - Cloud Kerberos Trust

• Default Applications:
  • Compromising an Application Administrator account or the on-premise Sync Account allows modification of directory settings, group memberships, user accounts, SharePoint sites, and OneDrive files.

Az - Default Applications

For each integration method, user synchronization is conducted, and an MSOL_<installationidentifier> account is created in the on-prem AD. Notably, both PHS and PTA methods facilitate Seamless SSO, enabling automatic sign-in for Azure AD computers joined to the on-prem domain.

To verify the installation of Azure AD Connect, the following PowerShell command, utilizing the AzureADConnectHealthSync module (installed by default with Azure AD Connect), can be used:

Get-ADSyncConnector