Active Directory Defense Essentials|Defender for Identity Explained

Understanding "Dedicated EDR" to Protect Active Directory

In enterprise security measures, endpoint (PC) and cloud service defenses are being strengthened every year. However, attacks targeting Active Directory (AD) continue to grow, and once compromised, they can be complicated at a company-wide scale.

In this article, we'll explain what Defender for Identity does for internal security professionals and what threats it can detect.

Why is Active Directory Targeted?

Active Directory is the core of your internal authentication foundation that centralizes user groups, devices, and permissions.
For attackers, taking control of AD means:

• Seize administrative privileges
• Horizontal deployment to all devices and users
• Long-term incubation by deleting logs and hiding traces

In real-world intrusion scenarios, we see a very common trend like this:

1. Your PC is compromised by phishing, etc.
2. Credentials are stealed on the device
3. Lateral expansion and privilege escalation occur in AD

This process often results in the exploitation of legitimate user credentials, and the challenge is that EDR alone does not provide sufficient visibility into suspicious behavior inside AD.

 

What is Defender for Identity?

Defender for Identity is a dedicated threat detection solution for Active Directory from Microsoft.

In a nutshell, these are the following products:

Analyze authentication, communication, and manipulation behaviors that occur on Active Directory to detect signs of compromise.

If Defender for Endpoint for endpoints is "EDR on PCs", then
Defender for Identity is easy to understand if you think of it as "EDR for Active Directory ."

 

What threats can be detected?

Defender for Identity analyzes not just the presence or number of logs, but also behavior patterns. Typical detections include:

(1) Credential Misuse

• Pass-the-Hash
• Pass-the-Ticket
• Golden Ticket Attack

These attacks are often overlooked by traditional perimeter defenses because they use legitimate credentials to gain unauthorized access.

(2) Horizontal expansion and internal exploration

• Unnatural LDAP query execution
• Use unusual admin privileges
• Behavior of connecting to multiple devices in a short period of time

You can explore within AD and detect phases to look for the next attack surface.

(3) Elevation of privileges and setting changes

• Add suspicious users to the Administrators group
• Incorrect attribute changes on AD objects

Because it is an area where "setting change = regular work", behavior-based detection is important.

 

Deployment Configuration and Basic Mechanics

Defender for Identity works by placing sensors on domain controllers.
This sensor collects and analyzes the following information:

• Authentication traffic
• Windows Event Log
• Network communication metadata

Detections are aggregated in the Defender portal and visualized as alerts. It can also be integrated with SIEMs such as Microsoft Sentinel to centrally monitor and analyze within SOC operations.

 

Role Division with EDR and SIEM

Some of the most common questions when deploying Defender for Identity include:

"I already have EDR and SIEM in place, do I still need it?"

The roles of each are summarized as follows:

• EDR: Monitor behavior on the device (malware, process, suspicious operation)
• Defender for Identity: Monitor behavior inside Active Directory
• SIEM: Aggregate logs from multiple products and perform correlation analysis

Defender for Identity complements the visibility of AD's most critical foundation, and is positioned to "augment" existing measures rather than replace them.

 

Benefits from a SOC perspective

From a SOC operations perspective, implementing Defender for Identity can have the following benefits:

• Early detection of AD attacks
• Quickly identify the scope of the breach (affected users and devices)
• Smooth coordination with CSIRT investigation and response

This product fills a critical security gap, especially for organizations that have EDR in but don't see what's going on inside AD.

 

Conclusion

Defender for Identity

• Advanced attacks targeting Active Directory
• Behavior-based detection
• Can be used in actual operation in conjunction with SOC / SIEM

It's the core solution for Active Directory security.

Now that Zero Trust and XDR are attracting attention,
From the perspective of "how to protect the authentication platform itself", it is worth reconsidering the introduction and utilization of Defender for Identity.

Colorkrew Security can support Defender for Identitiy from deployment to operation.
If you have any concerns such as being included in the Microsoft 365 E5 license but not being able to use it, please feel free to contact us.