Getting Inside the Mind of an Attacker: Why Active Directories Are Popular Targets

Authored by: Julio Sanchez

In today’s world, with the perpetual threat of breaches always looming, what’s the best way to ensure your organization stays safe? Oftentimes, the best security measure against cyber-attacks is to think like an attacker. When viewing things in this light, it’s immediately clear what makes for a prized gem within your infrastructure: Active Directory. Though such an attack is more complex than a simple phishing campaign, taking control of Active Directory provides so much power and possibility that attackers have learned and are willing to take the time to navigate different environments. Such threat actors are able to adapt quickly, using only what they enumerate from an organization to create new links in an attack chain in order to complete a successful compromise.

What makes Active Directory so important and how are attackers gaining access so frequently? This five part blog series will share four different scenarios and attack vectors used by Core Security’s own penetration testing services team to compromise Active Directory, along with ideas on how to identify and prevent them from happening. To begin, let’s explore what Active Directory is, why it holds such value to attackers, and the effects such a breach can have on an organization.

What is Active Directory?

Active Directory is one of the most critical applications within an organization, facilitating and centralizing network management in a number of ways, including domain, user, and object creation, as well as authentication and authorization of users. Active Directory serves as a database, storing usernames, passwords, permissions, and more. While Active Directory enables the efficient operation of an IT environment, having such crucial identity and administration information in one location also gives an attacker a focal point on which to target their efforts.

An attacker who has acquired domain admin rights to Active Directory essentially has the keys to the kingdom. They can attain the highest privileges in your organization, meaning they have the capability to access, create, or modify any of the main accounts. This includes all trust relationships and domain security policies.

Once an attacker has root privileges in Active Directory, the possibilities are seemingly endless. A threat actor could access all internal file shares and then proceed to leak sensitive information into the public sphere or sell it on the dark web. They could launch an internal DOS attack which would cripple the network. They could even install malicious software in your computers through remote deployment—meaning that they could launch additional attacks from anywhere.

The Long-Term Effects of Active Directory Attacks

Fully recovering from a domain or forced compromise is usually a lengthy, arduous effort, since such an attack damages the foundation of security upon which an organization’s infrastructure relies. Since an attacker would have already compromised every account, full recovery would likely require a massive password reset operation, including administrators, service owners, and machine accounts. This would take a great toll in the availability of the network systems and would greatly interrupt the regular flow of business operations.

Ultimately, it’s nearly impossible to tell the level of persistence an attacker has already gained in a network. So, even after each account has had their password reset, an attacker may have already embedded an efficient and hard to detect script that would enable them to regain privileges and reclaim the network. In short, an Active Directory attack can mean a security team has to start from scratch.

Exploring Different Attack Scenarios with Core Security Services

There are a number of ways that threat actors can take advantage of security weaknesses in order to gain access to Active Directory—misconfigurations, poor security policies, stolen credentials, and more. Many of these weaknesses stem from security pitfalls introduced by  users. Anyone from a regular user to an IT admin can make simple but critical errors that allow a threat actor to enter an organization’s network. In part 2, we’ll detail an example of how Core Security Services demonstrated how an external attacker can gain internal access, simply by doing recon and using a password spray attack. Don’t worry—we’ll also detail all the steps you can take to reduce your risk.