Dirk-jan Mollema

Dirk-jan Mollema

Hacker, red teamer, researcher. Likes to write infosec-focussed Python tools. This is my personal blog containing research on topics I find interesting, such as (Azure) Active Directory internals, protocols and vulnerabilities.

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Recent Posts

Digging further into the Primary Refresh Token

19 minute read

In my previous blog I talked about using the Primary Refresh Token (PRT). The PRT can be used for Single Sign On in Azure AD through PRT cookies. These cookies can be created by attackers if they have code execution on a victim’s machine. I also theorized that since the PRT and the cryptographic keys associated with it it are present on the victims device, they could be extracted from memory with the right tools. I wanted to further understand how the PRT works so I continued digging into it. Around the same time Benjamin Delpy took up my “challenge” of recovering PRT data from lsass with mimikatz. We combined forces and ended up with tooling that is not only able to extract the PRT and associated cryptographic keys (such as the session key) from memory, but can also use these keys to create new SSO cookies or modify existing...

Abusing Azure AD SSO with the Primary Refresh Token

21 minute read

Modern corporate environments often don’t solely exist of an on-prem Active Directory. A hybrid setup, where devices are joined to both on-prem AD and Azure AD, or a set-up where they are only joined to Azure AD is getting more common. These hybrid set-ups offer multiple advantages, one of which is the ability to use Single Sign On (SSO) against both on-prem and Azure AD connected resources. To enable this, devices possess a Primary Refresh Token which is a long-term token that is stored on the device, where possible using a TPM for extra security. This blog explains how SSO works with the Primary Refresh Tokens, and what some of the implicit risks are of using SSO. I’ll also demonstrate how attackers can abuse this if they have access to a device which is Azure AD joined or Hybrid joined, to obtain long-lived tokens which can be used independently of...

Introducing ROADtools - The Azure AD exploration framework

15 minute read

Over the past 1.5 years I’ve been doing quite a lot of exploration into Azure AD and how it works under the hood. Azure AD is getting more and more common in enterprises, and thus securing it is becoming a bigger topic. Whereas the traditional Windows Server Active Directory already has so much research and community tooling available for it, Azure AD is in my opinion lagging behind in this aspect. In this post I’m introducing the ROADtools framework and it’s first tool: ROADrecon. This framework was developed during my research and will hopefully serve as both a useful tool and an extensible framework for anyone that wants to analyse Azure AD, whether that is from a Red Team or a Blue Team perspective. This post is the first in part of a series in which I’ll dive into more aspects of Azure AD and the ROADtools framework. Both ROADtools...

Updating adconnectdump - a journey into DPAPI

10 minute read

Last year when I started playing with Azure I looked into Azure AD connect and how it stores its high privilege credentials. When I was revisiting this topic a few weeks ago, it turned out that some things had changed and my previous method of dumping credentials did not work anymore. Because it took me quite some time to figure out what exactly changed, and some help from @gentilkiwi to figure out the DPAPI process, I thought I’d document both the process and the results in the hope it will be useful for others.

Office 365 network attacks - Gaining access to emails and files via an insecure Reply URL

7 minute read

One of the main powers of Office 365 is the tight integration between all the online applications. At the same time this is a risk since those applications have access to other elements such as emails in Outlook or files on SharePoint/Onedrive. This means that if there is a vulnerability (for example an XSS) in one of these applications, the impact may not just be the data stored in that application, but also impact other data stored in Office 365. This blog discusses a vulnerability Microsoft Teams that allowed an attacker to access emails and files stored in Office 365 when they could convince a victim to connect to a rogue (wireless) network. I disclosed this to Microsoft earlier this year and the issue was resolved this week. More apps may be vulnerable to these kind of issues so make sure to check your organization’s environment for similar issues.