Back in 2017 I wrote a post on a PowerShell module I created that consumes Troy Hunt’s Have I Been Pwned API service. I won’t go into too much detail about the service here. Plenty of people already have and since that time HaveIBeenPwned has exploded in popularity and most of us know what it is.

In that post I briefly discussed what the module does how you can begin to use some of the core functions in it. Since that time Troy has made a few changes to the API service, some small and some large, which I’ve slowly integrated into the PowerShell module. Things like UserAgent strings being a requirement and K-anonymity for password checks.

The community has also played a part in shaping the PowerShell module over the last year. I’ve had a lot of feedback and even some contributions through the GitHub project. It’s been pretty cool to receive PRs via my GitHub page for improvements to the module.

I thought now was a good opportunity for a follow-up post to talk about some of the changes and updates that have been made over the last year.

Probably the biggest change has been K-anonymity in Get-PwnedPassword. Originally you would send your password over the air in the body of a HTTPS request. With K-anonymity, Get-PwnedPassword will now SHA1 hash your password locally first and will always just send the first 5 characters of the hash to the HaveIBeenPwned API. It’s a much safer way of checking passwords which hopefully will lead to more people accepting and trying this method.

PS F:\Code> Get-PwnedPassword -Password monkey
AB87D24BDC7452E55738DEB5F868E1F16DEA5ACE
WARNING: Password pwned 980209 times!

I’ve attempted to make the module and all functions as PowerShell Core compliant as I can. I say, attempted, because as much of a fan of PowerShell Core as I am I keep finding differences in the way Core works. I’ve had to rewrite all the error handling to better catch 404 responses. A 404 not found response actually being a good thing in identifying that an email account has not be found in a breach. So whether it’s Windows PowerShell or PowerShell Core you should now be fine.

In my original post I gave an example of how you could run Get-PwnedAccount against a CSV file of email accounts and bulk check all your email addresses. Something that could be helpful in a corporate environment with many 100s of email addresses. The example I gave though was far from ideal.

This ability is now baked into Get-PwnedAccount and should lead for some interesting results. It’s very easy to use. A simple text file saved in CSV format with each email address on a separate line / row. Incorrectly formatted email addresses will be ignored and results are displayed only for identified email addresses in breaches.

Below is an example of what the CSV file might look like

[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]

Usage is straight forward too.

PS F:\Code> Get-PwnedAccount -CSV F:\emails.csv

Description                   Email             Breach
-----------                   -----             ------
Email address found in breach [email protected]    000webhost
Email address found in breach [email protected]    17
Email address found in breach [email protected]    500px

Each time an email is found in a breach it will output a result as an object. So you may get multiple results for a single email due to different breaches it’s in.

Identifying the total emails found in breaches is simple. For example

PS F:\Code> Get-PwnedAccount -CSV F:\emails.csv |  Measure-Object | Format-Table Count

Count
-----
  413

Now you probably don’t want to be hitting the API every time you want to manipulate the data. It will be slow and I can’t guarantee that rate limiting may block you. Storing the results in a variable will provide a lot more flexibility and speed. For example, finding results just on one email address

PS F:\SkyDrive\Code> $results = Get-PwnedAccount -CSV F:\emails.csv
PS F:\SkyDrive\Code> $results | Where-Object {$_.email -eq "[email protected]"}

Or if you don’t care about the breach and just want to display a compromised email address once.

$results | Sort-Object Email -Unique | Select-Object Email

You get the point right!?!? It’s fairly flexible once you store the results in an array.

Finally one last small addition. Get-PwnedAccount will now accept an email from the pipeline. So if you have another cmdlet or script that can pull an email out, you can pipe that directly into Get-PwnedAccount to quickly check if it’s been compromised in a breach. For example checking an AD user email address could be done as follows…

PS F:\code> Get-ADUser myuser -Properties emailaddress | % emailaddress | Get-PwnedAccount

Status Description              Account Exists
------ -----------              --------------
Good   Email address not found. False

The HaveIBeenPwned PowerShell module can be downloaded from the PowerShellGallery. Always make sure you are downloading and using the latest version. Within PowerShell use Install-Module -Name HaveIBeenPwned. The project can also be found on my GitHub page where you can clone and fork the project.

I’m keen to hear suggestions and feedback. So please let me know your experiences.

Download Links
PowerShellGallery: https://www.powershellgallery.com/packages/HaveIBeenPwned/
GitHub: https://github.com/originaluko/haveibeenpwned