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Category: Security

A Warning: VPCs and Distributed Database Platforms

Published 2021-08-02 by Kevin Feasel

Wade Trimmer takes us through a reason why you might not want to use VPC endpoints to separate applications from distributed database platforms:

AWS PrivateLink (also known as a VPC endpoint) is a technology that allows the user to securely access services using a private IP address. It is not recommended to configure an AWS PrivateLink connection with Apache Kafka or Apache Cassandra mainly due to a single entry point problem. PrivateLink only exposes a single IP to the user and requires a load balancer between the user and the service. Realistically, the user would need to have an individual VPC endpoint per node, which is expensive and may not work. 

Using PrivateLink, it is impossible by design to contact specific IPs within a VPC in the same way you can with VPC peering. VPC peering allows a connection between two VPCs, while PrivateLink publishes an endpoint that others can connect to from their own VPC.

Read on to understand how this affects platforms like Cassandra and Kafka.

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Working with App Secrets in .NET Core

Published 2021-07-30 by Kevin Feasel

Santosh Hari shows us how to use application secrets when building .NET Core applications:

I was writing a sample dotnetcore console application for a talk because why I felt using a sample aspnet core web app was overkill. The app was connecting to a bunch of Azure cloud and 3rd party services (think Twilio API for SMS or LaunchDarkly API for Feature Flags) and I had to deal with connection strings.

Now I have a nasty habit of “accidentally” checking in connection string and secrets into public GitHub repositories, so I wanted to do this right from the get go.

That’s a bad habit to be in, and Santosh shows us how we can avoid doing that via use of application secrets.

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Handling Content Access Requests in Power BI

Published 2021-07-30 by Kevin Feasel

Marc Lelijveld walks us through the process of requesting (and granting) access to content in Power BI:

When we look at the Power BI ecosystem, we can identify a bunch of different artifacts. For example, dataflows, datasets, reports, dashboards and many derivatives. As I explained in the previous post, the best practice for sharing content is through a Power BI App, which includes a list of users or active directory group containing multiple users. With that, the content becomes available after publishing to those who are granted access. Though, it can happen that one of the users shares the link with other users who do not have access to the content. As a property of the Power BI App, you can allow users to share the app and underlying dataset with share permissions. Though, working with sensitive data this might now be what you are looking for, as you might loose control over who has access.

Read on to see what constitutes a content access request and what you can do about them.

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Digital Forensics with Apache Kafka

Published 2021-07-26 by Kevin Feasel

Kai Waehner continues a series on using Apache Kafka as the backbone for computer security:

Storing data long-term in Kafka is possible since the beginning. Each Kafka topic gets a retention time. Many use cases use a retention time of a few hours or days as the data is only processed and stored in another system (like a database or data warehouse). However, more and more projects use a retention time of a few years or even -1 (= forever) for some Kafka topics (e.g., due to compliance reasons or to store transactional data).

The drawback of using Kafka for forensics is the huge volume of historical data and its related high cost and scalability issues. This gets pretty expensive as Kafka uses regular HDDs or SDDS as the disk storage. Additionally, data rebalancing between brokers (e.g., if a new broker is added to a cluster) takes a long time for huge volumes of data sets. Hence, rebalancing takes hours can impact scalability and reliability.

But there is a solution to these challenges: Tiered Storage.

Click through to learn more.

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Threat Intelligence and Kafka

Published 2021-07-23 by Kevin Feasel

Kai Waehner continues a series on using Apache Kafka as the foundation for a security solution:

Threat intelligence, or cyber threat intelligence, reduces harm by improving decision-making before, during, and after cybersecurity incidents reducing operational mean time to recovery, and reducing adversary dwell time for information technology environments.

Threat intelligence is evidence-based knowledge, including context, mechanisms, indicators, implications, and action-oriented advice about an existing or emerging menace or hazard to assets. This intelligence can be used to inform decisions regarding the subject’s response to that menace or hazard.

Threat intelligence solutions gather raw data about emerging or existing threat actors & threats from various sources. This data is then analyzed and filtered to produce threat intel feeds and management reports that contain information that automated security control solutions can use.

Threat intelligence keeps organizations informed of the risks of advanced persistent threats, zero-day threats and exploits, and how to protect against them.

Read the whole thing.

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Unlocking a Login the Bad Way

Published 2021-07-23 by Kevin Feasel

Kenneth Fisher needs bad things done fast:

We recently had an application login (SQL Server authenticated) in one of our training environments start locking out on a regular basis. I won’t go into why other than to say we did resolve it eventually. This was a major problem that escalated rather quickly up our management chain. We needed to solve it ASAP. And because of that we needed not only a long term solution but a short term one as well. The short term solution involved creating a script that unlocked the login (if it’s currently locked) and sticking it in a job that runs every 5 minutes.

Note: This is not something you should be doing in production! This creates a major security hole.

The process itself isn’t, strictly speaking, a bad idea—for example, maybe you’re testing out some integration and accidentally lock the account. The bad idea is more the script to keep doing this every few minutes.

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Querying Private Blob Storage Containers with Azure Synapse Analytics

Published 2021-07-22 by Kevin Feasel

Dennes Torres looks at some private information:

The queries from the previous article were made against the public container in the blob storage. However, if the container is private, you will need to authenticate with the container. In this article, you’ll learn how to query private blob storage with SQL.

NOTE: Be sure that the Azure Synapse Workspace and the storage account with the sample files are set up before following along with this article. You will also need to replace your storage account URL each time that a storage account URL is used in the article.

There are three possible authentication methods, and these methods may have some variation according to the type of storage account and the access configuration. I will not dig into details about storage here and leave that for a future article.

Read on for the three authorization methods and a lot of detail on using SAS tokens (the preferred method) to access this data.

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How Dynamic Data Masking Interacts with Bulk Copy (BCP)

Published 2021-07-21 by Kevin Feasel

Kenneth Fisher puts on a lab coat:

Hypothesis: If I have Dynamic Data Masking enabled on a column then when I use something like BCP to pull the data out it should still be masked.

I’m almost completely certain this will be the case but I had someone tell me they thought it would go differently, and since neither of us had actually tried this out it seemed like time for a simple experiment.

Click through for the experiment and its results.

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Using Kafka for Security Situational Awareness

Published 2021-07-15 by Kevin Feasel

Kai Waehner continues a series on using Apache Kafka on security teams:

Apache Kafka became the de facto standard for processing data in motion across enterprises and industries. Cybersecurity is a key success factor across all use cases. Kafka is not just used as a backbone and source of truth for data. It also monitors, correlates, and proactively acts on events from various real-time and batch data sources to detect anomalies and respond to incidents. This blog series explores use cases and architectures for Kafka in the cybersecurity space, including situational awareness, threat intelligence, forensics, air-gapped and zero trust environments, and SIEM / SOAR modernization. This post is part two: Cyber Situational Awareness.

Click through for the high-level discussion.

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Power BI Report Server and Query Authentication

Published 2021-07-14 by Kevin Feasel

Emanuele Meazzo shows us the power of configuration:

With the end of the IE support for Power Bi (and in general tbh), companies are scrambling finally to move their users from the legacy browser to modern ones; it was about time if you ask me.
However, there’s an edge case where using anything but IE is not as straightforward as it could be; in my case Power Bi RS worked fine for any report in any browser, except with direct query reports that were set up to authenticate via Windows Authentication as the user viewing the report:

Read on to see how to fix this so that it works well in browsers like Edge and Chrome.

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