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Category: Security

Tips for Securing a SQL Server Instance

Published 2020-06-16 by Kevin Feasel

Eitan Blumin takes us through some ways of protecting an instance of SQL Server:

After reading up on a bunch of SQL Server penetration testing articles, I found that the steps of a common penetration test are as follows:

1. Discovery
2. Gaining Access
3. Elevating Permissions
4. Attacking (Loot / Destruction)

Logically, these steps mimic the steps taken by a common would-be hacker (except, of course, they try not to actually damage anything).

I’ll briefly describe each step from the point of view of a hacker or penetration tester, the common methodologies of each step, and offer recommendations that we can follow to protect our database systems at every level.

Click through for information on each step.

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Open-sourcing Kube2Hadoop

Published 2020-06-12 by Kevin Feasel

Cong Gu, et al, announce the open-sourcing of a project:

By default, there is a gap between the security model of Kubernetes and Hadoop. Specifically, Hadoop uses Kerberos, a three-party protocol built on symmetric key cryptography to ensure any clients accessing the cluster are who they claim to be. In order to avoid frequent authentication checks against a Kerberos server, Delegation Tokens, a lightweight two-party authentication method, was introduced to complement Kerberos authentication. The Hadoop delegation token by default has a lifespan of one day and can be renewed for up to seven days. Kubernetes, on the other hand, uses a certificate-based approach for authentication, and does not expose the owner of a job in any of its public-facing APIs. Therefore, it is not possible to securely determine the authorized user from within the pod using the native Kubernetes API and then use that username to fetch the Hadoop delegation token for HDFS access.  

To allow for Kubernetes workloads to securely access HDFS, we built Kube2Hadoop, a scalable and secure integration with HDFS Kerberos. This enables AI modelers at LinkedIn to use HDFS data in Kubernetes pods with access control through a user account or a headless account. Headless accounts are oftentimes used to denote a virtual team that is working on projects that would share the same data within the team. The data acquired can then be used in their model exploration and training with KubeFlow components such as the tf-operator and mpi-operator. In this blog, we will describe the design and authentication model of Kube2Hadoop. 

Read on to see how it works and a link to the GitHub repo.

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Azure Active Directory and the DatabricksPS Library

Published 2020-06-10 by Kevin Feasel

Gerhard Brueckl has updated the DatabricksPS library:

Databricks recently announced that it is now also supporting Azure Active Directory Authentication for the REST API which is now in public preview. This may not sound super exciting but is actually a very important feature when it comes to Continuous Integration/Continuous Delivery pipelines in Azure DevOps or any other CI/CD tool. Previously, whenever you wanted to deploy content to a new Databricks workspace, you first needed to manually create a user-bound API access token. As you can imagine, manual steps are also bad for otherwise automated processes like a CI/CD pipeline. With Databricks REST API finally supporting Azure Active Directory Authentication of regular users and service principals, this last manual step is finally also gone!

If you do use Databricks and haven’t tried out DatabricksPS, I highly recommend it. I think it’s a much nicer experience than hitting the REST API directly, particularly because it deals with continuation tokens and making multiple calls to get your results.

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Untrusted Shared Access Signature Certificates in SQL Server

Published 2020-06-03 by Kevin Feasel

William Assaf diagnoses an issue:

If you’ve tried doing Backup to URL with SQL Server using a Shared Access Signature (SAS) certificate and received this error:

Error: 18204, Severity: 16, State: 1.BackupDiskFile::CreateMedia: Backup device ‘https://account.blob.core.windows.net/container/folder/msdb_log_202005170801.trn’ failed to create. Operating system error 50(The request is not supported.).Cannot open backup device ‘https://account.blob.core.windows.net/container/folder/msdb_log_202005170801.trn’. Operating system error 50(The request is not supported.). [SQLSTATE 42000] (Error 3201) BACKUP LOG is terminating abnormally. [SQLSTATE 42000] (Error 3013). NOTE: The step was retried the requested number of times (1) without succeeding. The step failed. 

You may have received the same error I encountered.

This error popped up only after startup of SQL Server. To resolve the problem, we’d recreate the SAS key, using the same cert in the same script, and the backups would start working again. This affected all types of SQL database backups.

William did some troubleshooting and explains the core problem. It’s a weird one.

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Power BI Report Page Access Control

Published 2020-06-02 by Kevin Feasel

Gilbert Quevauvilliers walks us through access control on Power BI pages:

With the update to the latest version in Power BI Desktop there is now the capability to control which users will see which pages in a report.

This is achieved using a combination of Row Level Security (RLS) and conditional formatting. This makes it a secure way of controlling access for specific users. I will demonstrate how this works below.

This is a clever solution to the problem of access control.

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Replicating Permissions with dbatools

Published 2020-06-01 by Kevin Feasel

Claudio Silva shows how you can take one user’s permission set and apply it to another user with dbatools:

What are the steps involved in a process like this?

Generally speaking, the quickest way I know is:
1. Get the permissions of the source login/user (For each database because we don’t want to miss any permission)
2. Save them to a .sql file
3. Open the file and replace ‘srcUser’ by ‘newUser’
4. Execute

Claudio shows how you can accomplish this quickly.

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Securing a Kafka Deployment

Published 2020-05-29 by Kevin Feasel

Rick Spurgeon and Nikoleta Verbeck give us some tips on securing Apache Kafka:

Confluent Platform provides Role-Based Access Control (RBAC), which addresses the gaps listed above. RBAC and ACLs perform similar functions but approach the problem differently and can be used independently or cooperatively. RBAC is powered by Confluent’s Metadata Service (MDS), which integrates with LDAP and acts as the central authority for authorization and authentication data. RBAC leverages role bindings to determine which users and groups can access specific resources and what actions can be performed within those resources (roles). RBAC is empowered on the Kafka cluster by way of Confluent Server. Confluent Server is a fully compatible Kafka broker which integrates commercial security features like RBAC.

The list of items is pretty straightforward with no major surprises.

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TDE and Managed Instances

Published 2020-05-28 by Kevin Feasel

Tim Radney notes a change to the way new Azure SQL Database Managed Instance databases are configured:

Another recent change is that all newly created databases have “Encryption Enabled” set to True. This enables Transparent Data Encryption. By default, if you haven’t created your own key, it will use the service-managed key. A bug I’ve found in SSMS is that even though you set “Encryption Enabled” to false, it will still enable TDE. This is not the behavior when using T-SQL.

Read on to understand the ramifications of this change.

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Certificate Management with SQL Server 2019

Published 2020-05-12 by Kevin Feasel

Niko Neugebauer walks us through improvements in certificate management with SQL Server 2019:

If you have ever used them for connection encryption (TLS 1.2), you might have had some battles with the certificates, having to go into the registry to edit the thumbprint and if you doing a Failover Cluster or Availability Group installation – you would have to enjoy this operation on the multiple nodes. Not-so-very-user-friendly to say at least!
So many times, it would scare-off a non Server/Database Administrator or a junior Server/Database Administrator from trying those features.

Niko also mentions something very interesting about SQL Server Configuration Manager compatibility at the end of the post.

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Security Practices for Azure Databricks

Published 2020-05-07 by Kevin Feasel

Abhinav Garg and Anna Shrestinian walk us through good security practices when using Azure Databricks:

Azure Databricks is a Unified Data Analytics Platform that is a part of the Microsoft Azure Cloud. Built upon the foundations of Delta Lake, MLflow, Koalas and Apache SparkTM, Azure Databricks is a first party PaaS on Microsoft Azure cloud that provides one-click setup, native integrations with other Azure cloud services, interactive workspace, and enterprise-grade security to power Data & AI use cases for small to large global customers. The platform enables true collaboration between different data personas in any enterprise, like Data Engineers, Data Scientists, Business Analysts and SecOps / Cloud Engineering.

In this article, we will share a list of cloud security features and capabilities that an enterprise data team could utilize to bake their Azure Databricks environment as per their governance policy.

Much of this is fairly straightforward, but it is nice to have it all in one place.

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