Get-PwnedPassword.ps1

<#
.SYNOPSIS
Connects to the API at https://api.pwnedpasswords.com/ to see if a Password or Password hash has been found in a breach

.DESCRIPTION
Connects to the API at https://api.pwnedpasswords.com/ to see if a Password or Password hash has been found in a breach

Troy Hunt @troyhunt has created an API which allows you to query if a Password has been found in a breach. 
This is a simple function enabling you to query it

ONLY THE FIRST FIVE (5) CHARACTERS OF THE PASSWORD HASH ARE EVER SENT

.PARAMETER Password
The password to check as a secure string. If not supplied will be prompted

.PARAMETER Hash
A SHA1 hash of the password to be checked

.EXAMPLE
$Password = Read-Host -AsSecureString
Get-PwnedPassword -Password Password

Connects to the API at https://api.pwnedpasswords.com/ and checks if a password has been found
in a breach.


.EXAMPLE
Get-PwnedPassword -Hash 8be3c943b1609fffbfc51aad666d0a04adf83c9d

Connects to the API at https://api.pwnedpasswords.com/ and checks if the SHA1 hash of 'Password' has been found
in a breach.

Don't run this. It has!!

.EXAMPLE
Get-PwnedPassword

Prompts for a Password and connects to the API at https://api.pwnedpasswords.com/ and checks if it has been found
in a breach.

.NOTES
    AUTHOR : Rob Sewell @sqldbawithbeard https://sqldbawithabeard.com 
    DATE : 4th August 2017

    With many many thanks to Troy Hunt for creating this service
    You can find Troy on Twitter @TroyHunt
    You can read his blog at https://troyhunt.com 
    You should defintely sign up for his service at https://haveibeenpwned.com/ 
    to be notified when your email is in a breach
.LINK
https://www.troyhunt.com/introducing-306-million-freely-downloadable-pwned-passwords/
#>
function Get-PwnedPassword {
    [CmdletBinding(DefaultParameterSetName = 'Password')]
    Param(
        [Parameter(
            Mandatory = $true,
            Position = 1,
            ValueFromPipeline = $true,
            ParameterSetName = 'Password'
        )]
        [ValidateNotNullOrEmpty()]
        [SecureString]$Password ,
        [Parameter(
            Mandatory = $true,
            Position = 1,
            ValueFromPipeline = $true,
            ParameterSetName = 'Hash'
        )]
        [ValidateNotNullOrEmpty()]
        [String]$Hash
    )
    begin {
    }
    process {
        switch ($PSCmdlet.ParameterSetName) {
            'Password' {
                $Pass = (New-Object PSCredential "user", $Password).GetNetworkCredential().Password
                $StringBuilder = New-Object System.Text.StringBuilder
                [System.Security.Cryptography.HashAlgorithm]::Create("SHA1").ComputeHash([System.Text.Encoding]::UTF8.GetBytes($Pass))|% { 
                    [Void]$StringBuilder.Append($_.ToString("x2")) 
                }
                $sha1 = $StringBuilder.ToString()
                $sha1Prefix = $sha1.Substring(0, 5)
                $sha1Suffix = $sha1.Substring(5)

                $URL = 'https://api.pwnedpasswords.com/range/' + $sha1Prefix
                break
            }
            'Hash' {
                $sha1Prefix = $Hash.Substring(0, 5)
                $sha1Suffix = $Hash.Substring(5)
                $URL = 'https://api.pwnedpasswords.com/range/' + $sha1Prefix
                break
            }
            default {
                Write-Warning 'Unknown error occurred'
                exit
            }
        }
        [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
        try {
            $Response = Invoke-WebRequest -Uri $URL -ErrorAction SilentlyContinue
        }
        catch [System.Net.WebException] {
            Switch ($_.Exception.Message) {
                'The remote server returned an error: (400) Bad Request.' {
                    Write-Error -Message "Bad Request - the account does not comply with an acceptable format - Did you forget the password ?"
                }
                'The remote server returned an error: (404) Not Found.' {
                    Write-Output  "Hurrah! - No Password found - Congratulations this password has not been pwned. `nYou should still sign up for free at https://haveibeenpwned.com/ to be notified when your account is in a breach"
                }
                'The remote server returned an error: (429) Too Many Requests.' {
                    Write-Error -Message "Slow down! Too many requests — the rate limit has been exceeded"
                }
            }
            break
        }
        if ($Response.StatusCode -eq '200') {
            if ($Response.Content.Contains($sha1Suffix.ToUpper())) {
                # Password has been pwned
                Write-Warning -Message "Oh No! - Password has been pwned - Change it NOW! `nYou should sign up for free at https://haveibeenpwned.com/ to be notified when your account is in a breach"
            }
            else {
                Write-Output  "Hurrah! - No Password found - Congratulations this password has not been pwned. `nYou should still sign up for free at https://haveibeenpwned.com/ to be notified when your account is in a breach"
            }
        }
    }
    end {
    }
}
<#PSScriptInfo

.VERSION 1.3

.GUID bc54fa58-2ebc-4a87-8dd7-ecdcae505288

.AUTHOR Rob Sewell @sqldbawithbeard https://sqldbawithabeard.com 

.DESCRIPTION Connects to the API at https://api.pwnedpasswords.com/ to see if a Password or Password hash has been found in a breach. Troy Hunt @troyhunt has created an API which allows you to query if a Password has been found in a breach. This is a simple function enabling you to query it
      
.COMPANYNAME Sewells Consulting

.COPYRIGHT 

.TAGS Pwned,Password,TroyHunt

.LICENSEURI 

.PROJECTURI 

.ICONURI 

.EXTERNALMODULEDEPENDENCIES 

.REQUIREDSCRIPTS 

.EXTERNALSCRIPTDEPENDENCIES 

.RELEASENOTES

#>