Active Directory - The Heart of a Windows Server Network

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In this post, I will share with you why Active Directory is the heart of a Windows Server based network. Understanding this is critical to understanding why privilege escalation in Active Directory is so powerful.

We all know that there are just 3 basic things that help secure all the data in an environment -

1. Identity - Every user in the system is identified by a unique identity
2. Resource Authorization - Access to all resources is authorized based on group memberships
3. Host Management - The computers on which resources are stored need to be managed

Basically, every system needs way to identify its users, let them prove their identity with passwords, then protect the IT resources by letting admins configure who has what security permissions on them, and lastly to manage and protect the computers on which the IT resources are stored.

Of course, certain things like ability to have distributed authentication, authorization and auditing are also required, and exist to facilitate secure access for all users to all resources.

If you look at Active Directory simply, it is just one directory, and not of much interest because after all how interesting could a directory be? But if you look at Active Directory from angle that it contains all the 3 pieces requires to provide security in network, then it looks very important and in fact it is very important.

It is commonly known that all the user accounts are stored in Active Directory. In addition, the passwords of all these user accounts are also stored in the Active Directory. Furthermore, the management of these accounts is also delegated in Active Directory, meaning for example, that the information of who can reset the password of a user's account is also stored in Active Directory.

By similar token, all the security groups that are used to grant or deny some level of access to all files on file servers, databases on database servers and applications on application servers are also all defined, configured and managed in Active Directory. In particular, the membership of all such groups used across the network is stored in and controlled in Active Directory. Also, information about who can change the membership of these groups is also stored in Active Directory.

Also by similar token, all the policies that are used to protect all the computers in the network are also defined in and automatically pushed out from the Active Directory. Furthermore, data about who can change these policies and who can push them where is also stored in Active Directory.

So, from this angle, it is logical that Active Directory is the heart of a Windows Server based network. That is why lot of companies put in lots of resources to try and protect it as much as they can.

The interesting thing about Active Directory is that it lets powerful admins delegate specific operations (tasks) to specific delegated admins, thereby creating a hierarchy of power in the network.

This is very important for privilege escalation, because as we shall see in following posts, the ability to escalate privilege one by one in hierarchy starting from bottom and aiming for top is very valuable.

From the view of privilege escalation, Active Directory is a treasure box of information, because it is THE place where all the responsibilities for the management of all of these 3 things are delegated and controlled.

So if you are interested in learning more about how to escalate privilege in Windows networks, you should become familiar with Active Directory hierarchical and security model. Once you are familiar you can start experimenting yourself based on following posts on how to find and use privilege escalation opportunities to go from basic authenticated user to domain admin with just little effort.

In my next post, I will cover some details about Active Directory's storage and security model, to help you understand how to experiment with this concept in your test environment.

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Understanding the Concept of Privilege Escalation

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In order to understand what Privilege of Escalation in Active Directory is, it is first helpful to understand the concept of security privilege escalation in general.

Here is the definition of Privilege Escalation from Wikipedia -

Privilege escalation is the act of exploiting a bug, design flaw or configuration oversight in an operating system or software application to gain elevated access to resources that are normally protected from an application or user. The result is that an application with more privileges than intended by the application developer or system administrator can perform unauthorized actions.

To put it simply, security privilege escalation is the process by which someone can elevate the level of access they have in a security system, by exploiting some weakness of the system, or by using social engineering, to gain more access.

For example, lets say a user Alice only had the access to be able to read files on a file-server, but not to be able to modify the files. If Alice could somehow, i.e. by means of some actions, elevate the level of access granted to her so that she could now also modify files on the file-server, then in effect she would have escalated her privilege in the system to obtain more power.

For instance, Alice could exploit a weakness in the system itself, or discover weaknesses in access rights granted in the system which would allow her to enact some steps and ultimately gain elevated access, then she would have in effect elevated her security privilege in the system.

In other words, privilege escalation is a very powerful concept because it lets someone obtain more privilege in a system than he/she is supposed to have, and its consequences can be very serious, because a skilled individual could do a lot of damage to a system with escalated privileges.

Privilege escalation, when applied to Active Directory, is one of the most powerful ways in which someone could obtain administrative power in a Microsoft network, and potentially use it to cause widespread damage across the network.

In the next post, I will cover why the concept of privilege escalation is so pertinent to Active Directory, and how Active Directory's powerful but complicated security model makes it easy for anyone with read access to Active Directory to find many avenues of privilege escalation.

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Notes on Privilege Escalation in Microsoft Active Directory

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I am Nikolai. I live in Moscova. I am a security researcher, and my recent interest has been in the area of security of Microsoft Windows and Active Directory, with a focus on privilege escalation.

To help fellow comrades understand the concept of privilege escalation in Active Directory, I will share the theortical and practical aspects of the concept, and some ways in which one could try it out in lab environment.

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