Category: Microsoft Security

From DNSAdmins to Domain Admin, When DNSAdmins is More than Just DNS Administration

It’s been almost 1.5 years since the Medium post by Shay Ber was published that explained how to execute a DLL as SYSTEM on a Domain Controller provided the account is a member of DNSAdmins. I finally got around to posting here since many I speak with aren’t aware of this issue. Shay describes this …

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Domain Controller Print Server + Unconstrained Kerberos Delegation = Pwned Active Directory Forest

At DerbyCon 8 (2018) over the weekend Will Schroeder (@Harmj0y), Lee Christensen (@Tifkin_), & Matt Nelson (@enigma0x3), spoke about the unintended risks of trusting AD. They cover a number of interesting persistence and privilege escalation methods, though one in particular caught my eye. Overview Lee figured out and presents a scenario where there’s an account …

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Attacking Read-Only Domain Controllers (RODCs) to Own Active Directory

I have been fascinated with Read-Only Domain Controllers (RODCs) since RODC was released as a new DC promotion option with Windows Server 2008. Microsoft customers wanted a DC that wasn’t really a DC. – something that could be deployed in a location that’s not physically secure and still be able to authenticate users. This post …

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Securing Microsoft Active Directory Federation Server (ADFS)

Many organizations are moving to the cloud and this often requires some level of federation. Federation, put simply, extends authentication from one system (or organization) to another. Gerald Steere (@Darkpawh) and I spoke about cloud security at DEF CON in July 2017. Presentation slides and video are here: “Hacking the Cloud” One of the key …

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Beyond Domain Admins – Domain Controller & AD Administration

Active Directory has several levels of administration beyond the Domain Admins group. In a previous post, I explored: “Securing Domain Controllers to Improve Active Directory Security” which explores ways to better secure Domain Controllers and by extension, Active Directory. For more information on Active Directory specific rights and permission review my post “Scanning for Active …

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Detecting Kerberoasting Activity

Introduction Kerberoasting can be an effective method for extracting service account credentials from Active Directory as a regular user without sending any packets to the target system. This attack is effective since people tend to create poor passwords. The reason why this attack is successful is that most service account passwords are the same length …

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Sneaky Persistence Active Directory Trick #18: Dropping SPNs on Admin Accounts for Later Kerberoasting

The content in this post describes a method through which an attacker could persist administrative access to Active Directory after having Domain Admin level rights for about 5 minutes. Complete list of Sneaky Active Directory Persistence Tricks posts This post explores how an attacker could leverage existing admin rights and/or over-permissive delegation to gain persistence …

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Securing Domain Controllers to Improve Active Directory Security

Active Directory security effectively begins with ensuring Domain Controllers (DCs) are configured securely. At BlackHat USA this past Summer, I spoke about AD for the security professional and provided tips on how to best secure Active Directory. This post focuses on Domain Controller security with some cross-over into Active Directory security. The blog is called …

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