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Category: Security

Reviewing Encryption Code Snippets from Stack Overflow

Published 2021-09-16 by Kevin Feasel

Scott Contini explains some problems with popular encryption code snippets on Stack Overflow:

I’m not doing this to shame those who have made mistakes: Instead, I want to do my part to help fix the problem. As an AppSec specialist, I get really tired of having the same discussions over and over. I try real hard to make it easy for people to do the right thing: I point them to code that is safe to use, such as Luke Park’s Secure Compatible Encryption Examples. Despite this, there are the occasional teams who just continue to resist, even before the code has made it to production which is the best time to fix it. This makes everybody’s lives more difficult: it wastes my time to have to explain to them why their code is wrong, and it forces the teams to have to do a lot more work later because once the bad cryptography is in production, they need a migration plan to fix it.

Read on for a great explanation of common problems in encryption code.

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Azure Linux VM Agent Vulnerability

Published 2021-09-16 by Kevin Feasel

Nir Ohfeld finds another vulnerability:

Wiz’s research team recently discovered a series of alarming vulnerabilities that highlight the supply chain risk of open source code, particularly for customers of cloud computing services.

The source of the problem is a ubiquitous but little-known software agent called Open Management Infrastructure (OMI) that’s embedded in many popular Azure services.

When customers set up a Linux virtual machine in their cloud, the OMI agent is automatically deployed without their knowledge when they enable certain Azure services. Unless a patch is applied, attackers can easily exploit these four vulnerabilities to escalate to root privileges and remotely execute malicious code (for instance, encrypting files for ransom).

This has been patched, but it’s really ugly. H/T Ben Stegink.

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Role-Based Access Control in Snowflake

Published 2021-09-15 by Kevin Feasel

Warner Chaves explains how role-based access controls work in Snowflake:

The data access privilege granularity is the lowest level of securable that you will use to provide data access. This can theoretically go all the way down to rows and all the way up to full databases. 

I usually recommend that people start out with using Schema as their data access securable granularity. Database is usually too broad and you will inevitably have to re-do your roles and table level. Below is too specific to turn it into a general methodology—you would end up with way too many roles. See the FAQ later in this post on how to mix and match granularities if needed.

Once you have the granularity defined, you then create back-end roles at that level.

Read on to see what those roles look like. It’s a pretty standard RBAC setup.

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Patched Security Flaw in Azure Container Instances

Published 2021-09-10 by Kevin Feasel

Ionut Ilascu reports on a vulnerability:

Microsoft has fixed a vulnerability in Azure Container Instances called Azurescape that allowed a malicious container to take over containers belonging to other customers on the platform.

An adversary exploiting Azurescape could execute commands in the other users’ containers and gain access to all their data deployed to the platform, the researchers say.

This is fixed now, but it’s a good reminder that platform-as-a-service offerings can still have security problems (as we’ve also seen recently with Power Apps and Cosmos DB).

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Troubleshooting Microsoft.Purview not Registered

Published 2021-09-03 by Kevin Feasel

Wolfgang Strasser investigates an issue:

In my last Azure Purview Quickstart video (#3 – Create an Azure Purview Account – link), I’ve shown you how to create a new Azure Purview account.

And what pre-prepared demos have in common, well – it “just” works there 

BUT: there are some requirements that need to be configured beforehand, in order to create an Azure Purview Account.

Basically, problems during the creation process can be listed to:

– Security / permissions

– Missing Resource providers

Read on to learn more about permissions requirements and how to deal with these issues as they arise.

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Accessing Network Shares from SQL Server

Published 2021-09-02 by Kevin Feasel

Daniel Hutmacher engages in chicanery:

Using a local service account for your SQL Server service, your server won’t automatically have permissions to access to other network resources like UNC paths. Most commonly, this is needed to be able to perform backups directly to a network share.

Using a domain account as your SQL Server service account will allow the server to access a network share on the same domain, but if the network share is not on your domain, like an Azure File Share, you need a different solution.

There’s a relatively easy way to make all of this work, though.

Click through to see how, as well as several methods to make it work within SQL Server.

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Github Autopilot and Insecure Code Suggestions

Published 2021-08-30 by Kevin Feasel

Mayank Sharma reviews an article:

Academic researchers discover that nearly 40% of the code suggestions by GitHub’s Copilot tool are erroneous, from a security point of view.

Developed by GitHub in collaboration with OpenAI, and currently in private beta testing, Copilot leverages artificial intelligence (AI) to make relevant coding suggestions to programmers as they write code.

To help quantify the value-add of the system, the academic researchers created 89 different scenarios for Copilot to suggest code for, which produced over 1600 programs. Reviewing them, the researchers discovered that almost 40% were vulnerable in one way or another. 

Click through to learn more, as well as a link to the article itself. I would be interested in reading GitHub’s thoughts on this.

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Connecting to REST APIs via OAuth2 in Power BI

Published 2021-08-30 by Kevin Feasel

Chris Webb has an answer, but you may not like it:

There are a lot of articles and blog posts out there on how to handle OAuth2 authentication when connecting to REST APIs from Power Query in Power BI. However there is also a lot of confusion and contradictory information too so in this post I want to give you the definitive, Microsoft-endorsed answer to this question, which is:

If want to connect from Power BI to a REST API that uses OAuth2 authentication then you need to build a custom connector.

Read on for documentation showing how to implement and the big risk you’re taking if you don’t use a custom connector.

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Security Breach in Cosmos DB: ChaosDB

Published 2021-08-27 by Kevin Feasel

Nir Ohfeld and Sagi Tzadik discovered a flaw in Azure Cosmos DB:

Nearly everything we do online these days runs through applications and databases in the cloud. While leaky storage buckets get a lot of attention, database exposure is the bigger risk for most companies because each one can contain millions or even billions of sensitive records. Every CISO’s nightmare is someone getting their access keys and exfiltrating gigabytes of data in one fell swoop.

So you can imagine our surprise when we were able to gain complete unrestricted access to the accounts and databases of several thousand Microsoft Azure customers, including many Fortune 500 companies. Wiz’s security research team (that’s us) constantly looks for new attack surfaces in the cloud, and two weeks ago we discovered an unprecedented breach that affects Azure’s flagship database service, Cosmos DB.

Read on for details about the attack. Microsoft has already mitigated the issue by disabling the functionality necessary to pull off the attack. H/T Ben Stegink.

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