Category: Security

Now that our instance is set up to use AAD, let’s connect to our instance from SSMS. If you’re running Management Studio 2016 and SQL Server Data Tools for 2015 (14.0.60311.1) or later you should have noticed there are some extra authentication methods available in SSMS now. We’re going to cover these out of order, since some of these options take more work than others.

Active Directory Password Authentication looks similar to a SQL authentication, but it accepts AAD User names and passwords. When you choose this method, your credentials are sent over to Azure and end at your AAD instance. Once your username and password are validated, AAD will check to see if you have rights to connect to the instance. If so, you will connect. If not, you will get an error message that you’ll need to google (bing) to find out what it really means.

With the steps we took in the last section, you should be able to log in to your Azure SQL Server as an administrator by using Active Directory Password Authentication.

Click through for the process, as well as links to additional resources.

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Reversing Dynamic Data Masking

Published 2017-08-25 by Kevin Feasel

Joe Obbish shows how easy it is to reverse Dynamic Data Masking:

Armed with our new knowledge, we can create a single SQL query that decodes all of the SSNs. The strategy is to define a single CTE with all ten digits and to use one CROSS APPLY for each digit in the SSN. Each CROSS APPLY only references the SSN column in the WHERE clause and returns the matching prefix of the SSN that we’ve found so far. Here’s a snippet of the code:

Click through for progressively faster solutions. This is the main reason I do not care for DDM as a feature. Its main benefit seems to be preventing shoulder-surfing on reports; any concerted attacker with a little bit of access to writing queries can subvert it.

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When To Use Always Encrypted

Published 2017-08-25 by Kevin Feasel

Brent Ozar gives us some good pointers on when to use Always Encrypted:

But that comes with a few big drawbacks. They’re really well-documented, but here’s the highlights:

Do you need to query that data from other apps? Do you have a data warehouse, reporting tools, PowerBI, Analysis Services cubes, etc? If so, those apps will also need to be equipped with the latest database drivers and your decryption certificates. For example, here’s how you access Always Encrypted data with PowerBI. Any app that expects to read the encrypted data is going to need work, and that’s especially problematic if you’re replicating the data to other SQL Servers.

Click through to read the rest. Always Encrypted was designed to encrypt a few columns, not everything in a database.

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Storing Sensitive Information In SSIS

Published 2017-08-25 by Kevin Feasel

Shannon Lowder shows the complex interplay between Biml and SSIS when it comes to handling credentials:

One of the questions I get when teaching others how to use Biml is how do you deal with sensitive information like usernames and passwords in your Biml Solution. No one wants to leave this information in plain text in a solution. You need access to it while interrogating your sources and destination connections for metadata. You also need it while Biml creates your SSIS packages since SSIS uses SELECT to read the metadata during design time to gather its metadata. If you lock away that sensitive information too tightly, you won’t be effective while building your solutions.

In the end, you’ll have to compromise between security and efficacy.

Read on for more.

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Handling Sensitive Data With Powershell

Published 2017-08-23 by Kevin Feasel

Adam Bertram shows off the data protection API in Powershell:

We need to automatically read this information without our intervention. This is where you sometimes see people get lazy and add passwords in plain text into the script. That’s a big no-no, and there’s a better way.

PowerShell has native support for something called the data protection API (DPAPI). DPAPI is a built-in way Windows users can use certificates to encrypt and decrypt information on the fly which is perfect for PowerShell scripting. No username and password required. We simply need a certificate installed which can be self-signed.

This is about much more than storing and decoding passwords, so check it out.

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Enabling SQL Server SSL Encryption With Powershell

Published 2017-08-23 by Kevin Feasel

Tracy Boggiano shows how to create and put into place SSL encryption certificates on SQL Server instances using Powershell:

Next we take the exported pfx file and copy it locally to the temp folder of each machine and import into the local certificate store. Then we edit the registry with the thumbprint of the certificate. After that you will have to restart SQL Server to get the changes to take effect. We also clean up after ourselves and delete the pfx from the temp folder.

Note: To make this safe for production I commented out the restart of SQL Server. Also, Get-CmsHosts cmdlet can found here.

If you’re dealing with sensitive information, enabling (and forcing!) SSL encryption is one of the easiest effective ways of securing an instance; in this case, it’s securing data in transit from SQL Server to and from the client.

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Synchronizing Logins And Jobs

Published 2017-08-23 by Kevin Feasel

Ryan Adams shows five methods for synchronizing SQL logins and a couple ways of synchronizing SQL Agent jobs between instances of SQL Server:

Robert Davis wrote a great script back when he published his Mirroring book. I started to write my own and was almost done when I contacted Robert and asked if he had dealt with SQL logins since the script only handled Windows logins. His reply was something along the lines of, “What are you talking about? Of course it handles SQL logins”. It turns out that the publisher didn’t get the right script version published with the book. That’s when this post from Robert with the full script was born…

Transferring Logins

I also wrote about it HERE.

This script creates a stored procedure to handle the move and also uses Linked Servers. If you can’t have linked servers in your environment this is not a good choice for you. However, you can create the linked server in a SQL Agent job step prior to the step for transfer and then remove it in a job step after the transfer. It breaks the rule but it does it fast enough maybe no one will notice.

Read the whole thing.

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CLR Strict Security Done Easier

Published 2017-08-22 by Kevin Feasel

Solomon Rutzky continues his CLR Strict Security series with an easier way of creating a secure assembly:

This solution is easier than Solution 1:

8 steps instead of 22!

No extra Project

However, a very small amount of risk was added by overriding the default MSBuild workflow for SSDT. This risk can be eliminated if Microsoft provides a pre-defined Target for the appropriate event. Please upvote my suggestion to have this happen: Add MSBuild predefined Targets for “BeforeSqlBuild” and “BeforePublish” to SSDT SQL Server Data Projects.

ALSO: Even though we did not sign the assembly with a Strong Name Key, it is still probably a good idea to do that.

If you use CLR, this is worth the read.

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Talking To Secure Hadoop Clusters

Published 2017-08-18 by Kevin Feasel

Mubashir Kazia shows how to connect to a secured Hadoop cluster using Active Directory:

The primary form of strong authentication used on a secure cluster is Kerberos. Kerberos supports credentials delegation where a server process to which a user has authenticated, can perform actions on behalf of the user. This involves the server process accessing databases or other web services as the authenticated user. Historically the form of delegation that was supported by Kerberos is now called “full delegation”. In this type of delegation, the Ticket Granting Ticket (TGT) of the user is made available to the server process and server can then authenticate to any service where the user has been granted authorization. Until recently most Kerberos Key Distribution Center(KDC)s other than Active Directory supported only this form of delegation. Also Java until Java 7 supported only this form of delegation. Starting with Java 8, Java now supports Kerberos constrained delegation (S4U2Proxy), where if the KDC supports it, it is possible to specify which particular services the server process can be delegated access to.

Hadoop within its security framework has implemented impersonation or proxy support that is independent of Kerberos delegation. With Hadoop impersonation support you can assign certain accounts proxy privileges where the proxy accounts can access Hadoop resources or run jobs on behalf of other users. We can restrict proxy privileges granted to a proxy account to act on behalf of only certain users who are members of certain groups and/or only for connections originating from certain hosts. However we can’t restrict the proxy privileges to only certain services within the cluster.

What we are discussing in this article is how to setup Kerberos constrained delegation and access a secure cluster. The example here involves Apache Tomcat, however you can easily extend this to other Java Application Servers.

This is a good article showing specific details on using Kerberos in applications connecting to Hadoop.

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One CLR Solution

Published 2017-08-18 by Kevin Feasel

Solomon Rutzky continues his SQL Server 2017 CLR security series:

This new requirement prevents the technique described towards the end of Part 1 from working. That technique uses a SAFE Assembly as an indirect means of creating the Asymmetric Key to create the Login from. That worked perfectly prior to SQL Server 2017, but now even SAFE Assemblies require that the signature-based Login be created first, which now puts us in a whole chicken-egg paradox.

Before proceeding to the solution, it should be noted that yes, Microsoft has, as of RC2 (released on 2017-08-02), provided a kinda/sorta “fix” for this that allows for creating an Assembly without having the signature-based Login. HOWEVER, that “fix” is absolutely horrible, convoluted, and unnecessary. It should not be used by anyone. Ever! In fact, it should be completely removed and forgotten about. In no uncertain terms: it is not an option! To help clarify, I am being intentionally vague about that new feature here (and in Part 1) so as not to distract from these two solutions (this post and Part 3) that do not promote bad practices; it will be covered starting in Part 4.

Solomon outlines one approach to dealing with CLR security changes, though it’s a bit lengthy.

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