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Windows powerShell CLI

1. Execution Policy

Execution Policy is not a security measure. It's present to prevent user from accidentally executing scripts. PowerShell Execution Policy is by default set to Restriced. It means that user can execute single commands but not to run any PS script (.ps1 files).

Bypass methods don't require administrator privileges:

powershell -ExecutionPolicy bypass
powershell -c <cmd>
powershell -encodedcommand
$env:PSExecutionPolicyPreference="bypass"

2. Aliases

Most of the filtering cmdlets have useful aliases. All aliases can be listed using Get-Alias cmdlet. Most common ones:

select  -> Select-Object
where   -> Where-Object
sls     -> Select-String
measure -> Measure-Object
member  -> Get-Member

3. Special variables

$_                  # Current object
$?                  # Success ($true) or failure ($false) of the last command
$args               # Array of args passed to a function or script
$error              # Array of recent error objects ($Error[0] - most recent)
$false              # False value
$true               # True value
$null               # Null value

4. Calculated properties

Using @{} syntax we can specify calculated properties in one-liners. Inside the @{} we can specify many parameters (semicolon-separated). The most important ones are:

  • name (n) - name of the created property
  • expression (e) - script used to calculate the new property
# Example usage
<command> | select name,@{n="NewProp";e={ $_.Id + 1 }}

5. Loops

# Faster one-liner
$Objects.ForEach({
  # Your code here to be executed on every object
  Do-Something $_.ObjectProperty 
})
 
# Slower one-liner
$Objects | ForEach-Object -Process { $_.Length * 2 }
# Same as above but `%` is an alias
$Objects | %{ $_.Length * 2}

6. String interpolation

TBD

7. Cmdlet parameters

Parameters like all names in Powershell are case-insensitive. Powershell allows abbreviated parameter names until the parameter is no longer unambiguous. In shell use it's helpful but it's not recommended practice in scripts since a later version of the cmdlet may no longer have the abbreviation be unambiguous.

# Each of them are currently correct and unambigugous
$sth | Select-Object -First 10
$sth | Select-Object -fir 10 
$sth | Select-Object -f 10

To see exactly which parameters can be passed by pipeline or positionaly type Get-Help <command> -Full. There is a standarized list of all parameters with helpful attributes.

8. Utils

Get-Command | Out-File <file_path>          # Save output to :file_path

9. Invoke-Expression (iex)

TBD

10. Help

Get-Help <command|"About_<topic>">          # Get help about :command or :topic
    -Examples                               # Usage examples 
    -Full                                   # Full help content
 
Get-Command                                 # Get all commands          
Get-Command <verb>-*                        # Get all commands with :verb
Get-Command -Module <module>                # Get all commands from :module

11. Active Directory

11.1. Built-in cmdlets

Many built-in PowerShell cmdlets can work on Distiguished Names of objects. To use them in the Active Directory context add AD:\ before the actual DN string. Example usage:

(Get-Acl "AD:\<...DN...>").Access           # Get ACEs of an object
Get-ChildItem "AD:\<...DN...>"              # Get children items

11.2. Interesting user properties

Get-ADUser <user> -Properties *
 
# Using the following properties you can identify real users
badpwdcount                     # Number of invalid password attempts
logoncount                      # Number of logons

11.3. AD module convention

Server: AD commands can be executed against different domains or servers - select them using -server <domain> parameter:

Get-ADUser -Filter * -Server dom1.local
Get-ADComputer -Filter * -Server dom2.local

Filter: AD objects can be filtered before the response is generated (it's faster than filtering objects after the response is received already). Use -Filter '<query>' to filter objects (or * to fetch them all). Syntax inside the '<query>' is basically the same as for the Where-Object command: PropertyName -operator "value".

Get-ADComputer -Filter 'OperatingSystem -like "*2016*"'

IMPORTANT: A filter query needs to be written as a string! Best option is to use a single quote sign '.

Properties: AD objects usually have a large amount of properties. By default only small amount of them is actually returned from the DC. Use -Properties <prop1>,<prop2> to specify additional properties to fetch or * to select all of them.

Get-ADUser "user1" -Properties *

11.4. AD module

import-module ActiveDirectory
 
Get-ADObject <DN> -Properties *             # Get generic AD object
 
Get-ADDomain                                # Get object of current domain
Get-ADDomain <domain>                       # Get object of another domain
 
Get-ADDomainController                      # Get current Domain Controller
# Get Domain Controller of :domain
Get-ADDomainController -DomainName <domain> -Discover
 
Get-ADUser -Filter * -Properties *          # Get all users and properties
Get-ADUser <user> -Properties *             # Get all data of :user
# List built-in (default) users using their description field
Get-ADUser -Filter 'Description -like "*built*"' -Properties Description | select name,Description
 
Get-ADComputer -Filter *                    # Get all machines
Get-AdComputer <computer> -Properties*      # Get all data of :computer 
 
Get-ADGroup -Filter *                       # Get all groups
Get-ADGroup <group> -Properties *           # Get all data of :group
Get-ADGroup -Filter 'Name -like "*admin*"'  # Get all admin groups
 
Get-ADGroupMember <group> -Recursive        # Get members of :group
Get-ADPrincipalGroupMembership <user>       # Get group membership of :user
 
# GroupPolicy module required!
Get-GPO -All                                # Get all group policies
# Built-in tool
gpresult /R /V                              # Get policies TBD
 
Get-ADOrganizationalUnit -Filter *          # Get all OUs of current domain
 
Get-ADTrust -Filter *                       # Get current domain trust objects
Get-ADTrust -Filter * -Server <domain>      # Get :domain trust objects
 
Get-ADForest                                # Get current forest
Get-ADForest <forest>                       # Get current forest
(Get-ADForest).Domains                      # Get all domains of the forest

11.5. PowerView module

PowerView script propably will be detected by AMSI. An AMSI bypass method needs to be applied.

. .\PowerView.ps1                           # Load PowerView module
 
Get-DomainPolicy                            # Get domain policies
(Get-DomainPolicy).SystemAccess             # System access policy
(Get-DomainPolicy).KerberosPolicy           # Kerberos policy
 
# List all the local groups on a machine (admin privs required)
Get-NetLocalGroup -ComputerName <computer> -ListGroups
# List members of all the local groups on a machine (admin privs requored)
Get-NetLocalGroup -ComputerName <computer> -Recursive
 
# Get logged users on a computer (local admin privs on the target required)
Get-NetLoggedOn -ComputerName <computer>
# Get the last logged user on a computer (admin privs and remote registry on the target required) 
Get-LastLoggedOn -ComputerName <computer>
 
Invoke-ShareFinder -Verbose                 # Get shares in current domain
Invoke-FileFinder -Verbose                  # Get sensitive files in the domain
Get-NetFileServer                           # Get all file-servers in the domain
 
Get-NetGPO                                  # Get all group policies
Get-NetGPO -ComputerName <computer>         # Get GPOs for :computer
Get-NetGPO "{guid}"                         # Get GPO using :guid
 
# Get interesting ACEs associated with a :user
Get-ObjectAcl -SamAccountName <user> -ResolveGUIDs
Get-ObjectAcl -ADSprefix "<CN=...>"
 
Invoke-ACLScanner -ResolveGUIDs             # List interesting ACEs
 
# Find all machines in the current domain where the current user is local admin (very noisy!)
Find-LocalAdminAccess -Verbose
# Check if we have admin access to any machine
Invoke-UserHunter -CheckAccess
 
# Find domain machines where current user is logged into
Find-DomainUserLocation

12. Commands

Get-ChildItem                               # List files and folders
Get-Service                                 # List running services
Get-Process                                 # List running processes
Get-ScheduledTask                           # List scheduled tasks
Get-Location                                # Get current working directory
Get-Content <file>                          # Get :file content
Get-FileHash -Algorithm <alg> <file>        # Get :file hash
Test-Path <path>                            # Check if path exists
Invoke-WebRequest                           # Get content from a web resource
Get-LocalUser                               # List all local users
Get-LocalGroup                              # List all local groups
Get-NetIPAddress                            # List all network interfaces
Get-NetTCPConnection                        # List open TCP ports (connections)
Get-HotFix                                  # List Windows patches installed
Select-String                               # Find text in strings and files
Get-Acl                                     # Get ACL of a file/folder
Get-Alias                                   # List all command aliases
Test-Connection                             # Ping
 
# Find file
Get-Childitem 
    -Path C:\
    -Recurse 
    -ErrorAction SilentlyContinue 
    -File
    -Include *<file-name>*
 
# CIM interface
Get-CimInstace <class-name>                 # List CIM objects of :class
Get-CimClass *Process | select CimClassName # List all CIM Process classes
Get-CimInstance Win32_Product               # List installed software
Get-CimInstace Win32_Service                # List running services
Get-CimInstace Win32_Process                # List running processes