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Gaining Access
Nmap scan revealed standard AD ports, and that port 80 was open.
Hope Sharp
This website was another corporate domain. When scrolling through it, I found this image that was rather interesting.
If you look closely, there was a task with Send password to Hope Sharp. Then, IsolationIsKey? was the next line.
This tells me that there was an interesting password to find. As such, I created a bunch of possible usernames with the name Hope Sharp, and used crackmapexec to brute force these credentials. Found that hope.sharp was the username:
Additionaly, running feroxbuster on the website reveals some directories:
The /staff endpoint was interesting, but it was returning a 403 code.
Bloodhound
After getting these credentials, I wanted to use Bloodhound to map out all objects within the domain. Since I don't have a shell yet, I used bloodhound-python.
With Bloodhound, I found 2 interesting pieces of information. One was that a user named tristan.davies was a domain admin.
Another was that the web_svc user was Kerberoastable. We can then use GetUserSPNs.py to gain a hash and crack it.
web_svc shares
With this user's credentials, I enumerated the shares that were available.
I still don't have access to the helpdesk share, so I looked at the rest. Within the RedirectedFolders$ share, I found a ton of usernames.
Then, we can find out if the passwords we have are valid for any other users. I found that edgar.jacobs had the same password as the web_svc user.
Helpdesk Share
With this new user, I was finally able to access the helpdesk share.
Within the share, I found a .xlsx file.
Reading this file, I found out some usernames and names of users on the domain.
There was something odd however. Where was column C? The spreadsheet shows A,B and D. Perhaps column C was hidden on purpose because it contained other information. I was unable to expand it or view it, thus confirming it was locked.
Excel Bypass
This was a good read:
One cool thing about most .xlsx files is that they are actually ZIP files in disguise. We can bypass this content protection by copying the file as a .zip file, and then unzipping it.
Then from every single .xml file, we can remove the sheetProtection tag completely. Afterwards, we just need to compress and zip the files back together into another .xlsx file.
We can then view the hidden column C.
We can then brute force all of these passwords with crackmapexec and find that one works!
Using the RedirectedFolder$ share, we can sign in as the sierra.frye user and retrieve theuser flag.
Privilege Escalation
Looking around this user's directory, I was able to find a .pfx and .p12 file.
Certificate Loading
Because these are certificates, perhaps they can be loaded into our browser for viewing of hidden websites. However, they are password protected.
We can easily crack this with pfx2john and john.
Then we can load this in to our browsers.
Now, we can access the /staff page we were rejected from earlier. This would reveal a Powershell Web Access page.
We can login as sierra.frye usingthe credentials we found earlier. For Computer Name, I guessed search and research based on the certificates I found, and research worked.
Powershell Web Access
Now, we had a CLI as Sierra.frye.
Looking back to Bloodhound, I found that this user was able to ReadGMSAPassword for the bir-adfs-gmsa user, in which the latter had GenericAll privileges over the domain admin tristan.davies.
We can read the password using the Active Directory Powershell module.
Then, we can store the password in a variable (because it's UTF-8 characters and hard to type) and just use Powershell to execute commands remotely.
Then, because we have GenericAll permissions over tristan.davies, we can just reset his password.
Lastly, we can use wmiexec.py to gain a shell as the domain admin.
