UPDATED: Identifying Active Directory Users with Pwned Passwords using Microsoft/Forefront Identity Manager

Earlier this week I posted this blog post that showed a working example of using a custom Pwned Password FIM/MIM Management Agent to flag a boolean attribute in the MIM Service to indicate whether a users password is in the pwned password dataset or not. If you haven’t read that post this won’t make a lot of sense, so read that then come back.

The solution when receiving a new password for a user (via Microsoft Password Change Notification Service) was checking against the Have I Been Pwned API. The disclaimer at the start of the blog post detailed why this is a bad idea for production credentials. The intent was to show a working example of what could be achieved.

This update post shows a working solution that you can implement internal to a network. Essentially taking the Pwned Password Datasets available here and loading them into a local network SQL Server and then querying that from the FIM/MIM Pwned Password Management Agent rather than calling the external public API.

Creating an SQL Server Database for the Pwned Passwords

On my SQL Server using SQL Server Management Studio I right-clicked on Databases and chose New Database. I gave it the name PwnedPasswords and told it where I wanted my DB and Logs to go to.

Then in a Query window in SQL Server Management Studio I used the following script to created a table (dbo.pwnedPasswords).

use PwnedPasswords;
 CREATE TABLE dbo.pwnedPasswords
( password_id int NOT IDENTITY(1,1) NULL,
 passwords varchar(max) NOT NULL,
 CONSTRAINT passwords_pk PRIMARY KEY (password_id)
);

Again using a query window in SQL Server Management Studio I used the following script to create an index for the passwords.

USE [PwnedPasswords]USE [PwnedPasswords]
GO
SET ANSI_PADDING ON

GO
CREATE UNIQUE NONCLUSTERED INDEX [PasswordIndex] ON [dbo].[pwnedPasswords]( [password_id] ASC)INCLUDE ( [passwords]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)
GO

The last thing I did on the DB was to take the MIM Sync Server Active Directory Service Account (that was already in the SQL Server Logins) and give that account Reader Access to my new PwnedPasswords Database. I gave this account access as I’m using Integrated Authentication for login to SQL and as the MA is initiated by the MIM Sync Service Account, that is the account that needs the access.

Getting the Pwned Password Datasets into the new Database

I’m far from a DBA. I’m an identity guy. So using tools I was most familiar with (PowerShell) I created a simple script to open the password dump files as a stream (as Get-Content wasn’t going to handle the file sizes), read in the lines, convert the format and insert the rows into SQL. I performed the inserts in batches of 1000 and I performed it locally on the SQL Server.

In order to get the content from the dump file, add another column and get it in a format quickly to insert into the SQL DB I used the Out-DataTable function available from here.

The script could probably be improved as I only spend about 20-30 minutes on it. It is opening and closing a connection to the SQL DB each time it inserts 1000 rows. That could be moved outside the Insert2DB Function and maybe the batch size increased. Either way it is a starting point and I used it to write millions of rows into the DB successfully.

Updated FIM/MIM Pwned Passwords Management Agent Password.ps1 script

This then is the only other change to the solution. The Password.ps1 script rather than querying the PwnedPasswords API queries the SQL DB and sets the pwned boolean flag accordingly.

Summary

This enhancement shows a working concept that will be more appealing to Security Officers within corporate organisations if you have an appetite to know what your potential exposure is based on your Active Directory Users Passwords.