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At this year’s YellowHat conference in Almere, the Dutch security community had the chance to participate in a Capture The Flag (CTF) competition organized by one of the conference sponsors - Blu Raven. Mehmet from Blu Raven did a great job setting up a CTF with realistic scenarios and datasets, which made it a lot of fun to solve the challenges. Foreword Being a big fan of CTFs and digital forensics and incident response (DFIR) in general, I couldn’t resist the temptation to participate. After numerous attempts to solve the first challenge and an enlightening tip from a colleague, I made some progress and solved the first 12 challenges. ...

Did you know that the maester framework now supports Microsoft Intune checks? In this blog post, I’ll give you a quick overview of the new capabilities and how to get started. About Maester Maester is an open-source security assessment framework that helps you evaluate the security posture of your Microsoft Entra ID and Microsoft 365 environments. It provides a collection of tests that can be run against your tenant to identify potential misconfigurations and security risks. ...

In May I had the pleasure to be invited to the KQL Café which is hosted by Gianni Castaldi & Alex Verboon. Within this format they empower people to work with KQL and share various tips and tricks. So this is not a usual blogpost but rather a summary and resource hub for the things I presented within the KQL Café. Summary To make the content of my talk more accessible, you can find a summary of the individual topics, including the leveraged KQL queries and further resources as part of this post. The KQL queries were mostly consuming the Entra ID Sign-In and Audit Logs. You can forward them to your Microsoft Sentinel or Log Analytics workspace. ...

Recently I stumbled over a nice post from Wesly Neelen who built an AiTM phishing toolkit based on a cloudflare worker. Although ‘prooven’ AitM phishing toolkits such as evilginx provide more capabilities in terms of flexibility and robustness I wanted to setup my own phishing toolkit that runs serverless on Azure — based on Azure Functions to phish some Entra ID credentials and cookies. Advantages of serverless phishing toolkits Serverless platform solutions such as Cloudflare workers, AWS lambda and Azure functions provide some advantages to phishing toolkits that are server-based: ...

With the availability of passkeys the FIDO2 standards become more accessible in the form of password managers, web-browsers and (mobile) operating systems — without the need for dedicated hardware such as FIDO2 keys. Microsoft is currently in the process of developing support for passkeys and shipping the public preview in Q1 2024: While this is a very welcome addition to make passwordless authentication easily accessible without dedicated hardware such as FIDO2 security keys this also introduces new risks, especially for high value accounts — But why’s that? ...

Microsoft 365 Defender and Sentinel provide an IdentityInfo table that contains various information that is helpful for threat hunting and detections. One key piece are also the assigned Entra directory roles for a specific identity. Unfortunately only permanently assigned permissions are covered and in times of Entra Privileged Identity Management (PIM) we should have standing permissions only for non-privileged roles and break-glass accounts. Within this blog post I want to share a few tips and tricks to answer the following questions with Sentinel and a little bit of scripting and KQL: ...

Microsoft Sentinel Analytic Rules can be shared in both the YAML and ARM format, whereas the ARM format leverages JSON as file type. Within… Microsoft Sentinel Analytic Rules can be shared in both the YAML and ARM format, whereas the ARM format leverages JSON as file type. Within this short post I want to demonstrate an approach that leverages a GitHub Action to automatically build and update the rules in YAML format — so you can just export and update existing rules without any manual conversion effort. ...

Microsoft recently made the Microsoft Graph Activity Logs available as part of the Microsoft Entra ID diagnostic settings. This means we can use the MicrosoftGraphActivityLogs Table to enrich custom detections and analytic rules. Within this post I want to elaborate closer on an attack scenario for workload identities that leverage workload identity federation and don’t have any persistent credentials or long lived secrets. But one type of credential artefacts is still theft-able — the short lived access tokens. ...

Microsoft Entra Connect Sync (aka Azure AD Connect) allows establishing hybrid identity scenarios by interconnecting on-premises Active Directory and Entra ID (aka Azure AD) and leveraging synchronisation features in both directions. As you might already know, this brings potential for abuse of the assigned permissions to the involved service accounts and permissions of this service. On the internet are already some posts with subset of this information but I wanted to provide an actionable post with individual measures to implement. Of course should we do MFA for all admins and AD tiering but some of those steps involve more complex measures to implement and I will try to provide some individual building blocks you can use to harden the configuration of your Entra Connect service accounts. ...

Microsoft Entra Workload Identity Federation is a hidden gem when dealing with app registrations and service principals because it will significantly improve the security posture of your workload identities. While I already blogged about the more technical and implementation specific details in my GitHub Actions with Entra Workload Identity Federation post, I want to highlight the benefits and scenarios where you can use Workload Identity Federation to access Entra ID protected resources. ...