First off, I want to state that the purpose of writing this post is to help myself learn how to use Golden Tickets on assessments. If you want to see some great write-ups about Golden ticket generation, be sure to look at these:
- Mimikatz Wiki
- Raphael Mudge’s Writeup on Meterpreter’s Kiwi Extension
- Raphael Mudge’s Writeup on Passing the Golden Ticket with Beacon
Those posts are significantly more authoritative on the subject than mine, I just wanted to write this out so I can reference this on assessments.
Golden tickets can offer an extremely powerful to escalate privileges for an attacker on a network, or obtain access to resources which are only available to a select group. However, it’s absolutely worth mentioning that with this great power, pen testers need to take extra precaution to protect any golden tickets that they’ve created. It’s highly recommended that any tickets created should be securely encrypted during your assessment, and securely deleted when it is no longer needed.
Golden Tickets can be generated two different ways. The first way is through the kiwi extension in Metasploit, and the other is through Mimikatz’s stand alone application. This post will show how to use both options to generate your ticket. Lets start off with Metasploit’s Kiwi Extension.
At this point, I am going to assume that you have a meterpreter session, as SYSTEM, on the domain controller for the domain you are targeting. Within your session, you want to load the kiwi extension by typing:
Now that the kiwi extension is loaded, when you type help, you should see the additional commands that are available for you. The command that we’re interested in is golden_ticket_create. In order to create the golden ticket, we’re going to need at least four pieces of information (tickets can be further customized with additional information, but the generation process needs a minimum of four):
- The Domain Name
- The Domain SID
- The krbtgt account’s nt hash
- The user account you want to create the ticket for
To get this information, you can just interact with the meterpreter session you already have active. Drop into a shell, and run:
The domain SID starts at the S-1… and goes to …70370. Copy and paste that information into a text file. Next up, grab the domain name. One way I like to do this is just running:
In this case, I can see (and I know) the domain name is PwnNOwn.com. So, this info should also be saved off to a text file. The last big hurdle that you will need is the nt hash from the krbtgt account. Since you should be on the DC, perform a hashdump and obtain the krbtgt hash.
Now that we have all of the required information, we can generate a golden ticket! At this time, go ahead and determine the user account you are wanting to impersonate, or, you can actually use an account that is nonexistent. Now, it’s just getting everything in place for the command. In our case, the command looks like this:
golden_ticket_create -d PwnNOwn.com -k <nthash partially redacted> -s S-1-5-21-522332750-710551914-1837870370 -u invaliduser -t /root/Downloads/invaliduser.tck
We can see from the previous picture that the ticket was successfully created and written out. The user that we are impersonating is “invaliduser”, and the ticket is saved to /root/Downloads/invaliduser.tck.
Now that the ticket has been created, it’s time to apply it to our current session. To do this you want to type the following command:
In the above screenshot, I cleared all existing tickets, then applied the created ticket, and then we can see the golden ticket in use. Note: you don’t have to purge existing tickets, but I did for demonstration purposes.
Now that the ticket has been applied, a low level user account can now act as a Domain Administrator:
The user account could not previously access the DC’s C$ share, but with the ticket applied, it can! We’re now operating with the same level of permissions as a DA!
So, our other option for generating and using golden tickets is to use the mimikatz binary. You can download that from here. Once downloaded, navigate to the mimikatz binary and start it. We can re-use the information that we already have to generate our golden ticket. To generate the ticket, you’re going to run a command similar to the following:
kerberos::golden /user:invaliduser2 /domain:PwnNOwn.com /sid:S-1-5-21-522332750-710551914-1837870370 /krbtgt:<ticket partially redacted> /ticket:invalidadmin.tck /groups:501,502,513,512,520,518,519
(Thanks to Benjamin Delpy (@gentilkiwi) for letting me know that I failed at redacting my own krbtgt hash, haha. This is why you should always post things from a test/lab domain :). Pic below is now updated)
In this case, we’re creating a ticket for a non existent user account, the User ID is at its default value (500), and we’ve added groups that the user should be part of. The ticket is saved to the invalidadmin.tck file within the same directory that the mimikatz binary is running from.
Now that the ticket has been created, we just want to apply it with Mimikatz. This can be done by running the following command:
And to verify that we have administrative access to the domain controller again…
We can actually also see from the DC that the Logon was successful, even though it was with an account that doesn’t exist within the domain!
And that’s about it! Writing this out helped me gain a better understanding about generating and using golden tickets, hope that it can help someone else too!