Unleashing the Power of CopyCat(C2) to Defeat APTs

Table of Contents

1. Introduction
2. The Challenge of Purple Teaming
3. The Role of Copycat in Purple Teaming
4. Understanding Purple Teaming
   • 4.1 The Concept of Purple Teaming
   • 4.2 The Structure of a Purple Teaming Exercise
5. The Copycat C2 Infrastructure
   • 5.1 The Components of a C2 Infrastructure
   • 5.2 The Function of a C2 Server
   • 5.3 Deploying Binaries On Target Systems
6. The Copycat C2 Architecture
   • 6.1 The High-Level Overview of the C2 Architecture
   • 6.2 Using Reverse TCP Communication Channels
   • 6.3 The Role of Stagers in C2 Frameworks
7. Building a Copycat C2 Framework
   • 7.1 The Tech Stack for Copycat
   • 7.2 Implementing the C2 Listener
   • 7.3 Creating the Infinite Loop
   • 7.4 Spawning Threads for Each Connection
8. Conducting APT Research for Copycat
   • 8.1 Identifying APTs to Emulate
   • 8.2 Selecting Actions to Implement
   • 8.3 Emulating APT Actions with Copycat
9. Supported APT Profiles in Copycat
   • 9.1 Turla Dark Neuron: Malicious Macro Campaign
   • 9.2 WinNTI Backdoor: Linux Variant
10. Custom Modules in Copycat
    • 10.1 The Fishing Framework
    • 10.2 The Keylogger Tool
    • 10.3 The ImplantF Module
    • 10.4 The Registry Manipulation Module
11. Conclusion

Introduction

Welcome to this article on how to conduct effective purple teaming exercises using the tool called Copycat. In this article, we will explore the concept of purple teaming and the challenges faced in such exercises. We will dive into the details of Copycat's C2 infrastructure, its architecture, and the process of building a Copycat C2 framework. We will also discuss the importance of APT research and the supported APT profiles in Copycat. Furthermore, we will explore the custom modules incorporated in Copycat, including the fishing framework, keylogger tool, implantF module, and registry manipulation module. By the end of this article, You will have a comprehensive understanding of how to leverage Copycat for successful purple teaming operations.

The Challenge of Purple Teaming

Purple teaming is an essential practice in the cybersecurity field, allowing organizations to evaluate and enhance their security defenses. However, traditional red teaming exercises only focus on the skills and tactics of the red team, overlooking the capabilities of real-world attackers. This challenge led to the need for purple teaming, where the red and Blue teams collaborate to share knowledge and improve each other's capabilities. The main challenge faced in purple teaming exercises is testing the blue team's ability to detect and respond to external APTs (Advanced Persistent Threats) that mimic real-world attack scenarios. This challenge requires a Novel approach and toolset to accurately emulate APT actions and test the blue team's detection capabilities.

The Role of Copycat in Purple Teaming

Copycat is a powerful tool developed to address the challenge of testing the blue team's ability to detect external APTs. It enables red and blue teams to collaborate effectively, improving both detection and evasion techniques. Copycat achieves this by automating APT emulation and providing a framework for implementing custom modules. With its comprehensive C2 infrastructure and extensive APT profiles, Copycat enables organizations to conduct realistic purple teaming exercises, enhancing their overall security posture.

Understanding Purple Teaming

4.1 The Concept of Purple Teaming

Purple teaming is a collaborative approach where the red and blue teams join forces to enhance an organization's security capabilities. The red team, acting as real-world threat actors, attempts to penetrate systems and find vulnerabilities, while the blue team focuses on detecting and responding to these attacks. By working together, the red and blue teams can improve their understanding of each other's roles and enhance their overall effectiveness in defending against advanced threats.

4.2 The Structure of a Purple Teaming Exercise

A typical purple teaming exercise involves setting up a test environment where the red and blue teams can collaborate. The red team conducts attacks using a variety of tactics, techniques, and procedures (TTPs), while the blue team closely monitors the environment for any signs of compromise. The blue team's goal is to detect and respond to these attacks effectively, closing any security gaps or weaknesses identified during the exercise. Through continuous collaboration and knowledge-sharing, both teams strive to improve their detection and response capabilities, thereby strengthening the organization's overall security.

The Copycat C2 Infrastructure

5.1 The Components of a C2 Infrastructure

In order to effectively emulate APT actions, Copycat utilizes a robust command and control (C2) infrastructure. The C2 infrastructure consists of three key components: the C2 server, the payload implants, and the victim systems. The C2 server acts as a central management point, enabling the attacker to control compromised systems and communicate with the payload implants. The payload implants are used to compromise and establish control over the victim systems, while the victim systems serve as the target for APT actions.

5.2 The Function of a C2 Server

The C2 server is the heart of the C2 infrastructure, providing essential capabilities for managing compromised systems and establishing communication with the payload implants. It allows the attacker to issue commands, receive data, and control the actions of the compromised systems. The C2 server is responsible for managing the communication channels, ensuring seamless interaction between the attacker and the compromised systems.

5.3 Deploying Binaries on Target Systems

One crucial functionality provided by the C2 infrastructure is the ability to deploy binaries on target systems. This capability allows the attacker to install malicious software or execute specific commands on compromised systems. By leveraging this functionality, the attacker can further exploit vulnerabilities, escalate privileges, or perform any other necessary actions to achieve their objectives.

The Copycat C2 Architecture

6.1 The High-Level Overview of the C2 Architecture

The Copycat C2 architecture follows a high-level overview that encompasses the necessary components for effective APT emulation. It includes the attacker, who controls the C2 infrastructure; the APT profiles, which define the actions of each APT group; and the campaigns, which represent the specific actions taken by an APT during an attack. By detailing these components, Copycat allows organizations to accurately replicate APT actions and test their defenses effectively.

6.2 Using Reverse TCP Communication Channels

One of the communication channels used in the Copycat C2 infrastructure is the reverse TCP communication channel. This channel enables seamless communication between the C2 server and the compromised systems, allowing the attacker to issue commands, receive data, and maintain control over the compromised systems. By leveraging the reverse TCP communication channel, Copycat ensures effective communication and coordination between the attacker and the compromised systems.

6.3 The Role of Stagers in C2 Frameworks

Stagers play a critical role in C2 frameworks, aiding in the successful execution of payloads on compromised systems. They act as intermediary components between the C2 server and the compromised systems, optimizing the payload's chances of success and evading detection. Stagers often assess the target system's operating system, software, and security protections to ensure the most effective payload delivery. By incorporating stagers into the C2 architecture, Copycat enhances the success rate of APT actions and improves evasion techniques.

Building a Copycat C2 Framework

7.1 The Tech Stack for Copycat

Copycat utilizes the Go language for both its C2 code and backdoor code. The choice of Go as the programming language for Copycat offers several advantages, including its platform versatility, simplicity, and speed. Go has proven to be reliable across different operating systems, fostering seamless deployment of Copycat on various target systems. Additionally, Go's simplicity allows for easy adoption by developers with programming experience in other languages, while its speed enhances the overall performance and efficiency of Copycat.

7.2 Implementing the C2 Listener

The Copycat C2 framework includes a TCP listener implemented using the Go net Package. This listener is responsible for opening the Relevant port and listening for incoming connections from compromised systems. By leveraging the net package's capabilities, Copycat ensures a robust and reliable listener that can handle multiple connections and facilitate effective communication between the C2 server and compromised systems.

7.3 Creating the Infinite Loop

To maintain continuous availability and readiness, the Copycat C2 framework incorporates an infinite loop. This loop is responsible for continuously listening for connections, ensuring the C2 server is always open for communication with compromised systems. By utilizing an infinite loop, Copycat guarantees that the C2 infrastructure is always operational and ready to handle communication from compromised systems.

7.4 Spawning Threads for Each Connection

The Copycat C2 framework utilizes threads to handle individual connections from compromised systems. By spawning a separate thread for each connection, Copycat can effectively handle multiple compromised systems simultaneously, ensuring optimized performance and responsiveness. The use of threads enables the C2 server to handle communication from compromised systems in a Parallel fashion, improving overall efficiency.

Conducting APT Research for Copycat

8.1 Identifying APTs to Emulate

To achieve accurate APT emulation, Copycat relies on a robust research process to identify the specific APT groups to emulate. This process involves gathering intelligence from various online resources, including external threat intelligence teams, internal security operations centers, and open-source platforms. By leveraging these resources, Copycat can effectively identify APTs and determine their tactics, techniques, and procedures (TTPs).

8.2 Selecting Actions to Implement

Once the APTs to emulate have been identified, Copycat conducts in-depth research to select the specific actions to implement. This research involves analyzing APT reports, code samples, and IOC extractions to gain insights into the APTs' tactics. By studying these resources, Copycat can accurately replicate the actions of the APTs, ensuring realistic APT emulation during purple teaming exercises.

8.3 Emulating APT Actions with Copycat

Copycat implements the selected APT actions by creating profiles and campaigns within the APT profiles. Each profile represents a specific APT group, while campaigns represent the actions taken by the APT during an attack. Copycat incorporates customized code modules to ensure accurate and effective APT emulation. By leveraging the research findings, Copycat enables organizations to replicate APT actions and test their defenses against real-world attack scenarios.

Supported APT Profiles in Copycat

9.1 Turla Dark Neuron: Malicious Macro Campaign

Copycat supports profiles for various APT groups, including Turla Dark Neuron. This profile specifically focuses on emulating the initial entry tactics used by Turla Dark Neuron, such as spear phishing campaigns. Through the implementation of malicious macros and the execution of payloads, Copycat replicates the actions taken by Turla Dark Neuron, allowing organizations to assess their detection and response capabilities.

9.2 WinNTI Backdoor: Linux Variant

Another supported APT profile in Copycat is the WinNTI backdoor, with a specific focus on the Linux variant. Copycat enables organizations to emulate the actions of WinNTI on Linux systems, replicating the backdoor functionalities and assessing the effectiveness of their defenses against this APT group. By accurately emulating the actions of WinNTI, organizations can enhance their detection and response capabilities.

Custom Modules in Copycat

10.1 The Fishing Framework

Copycat incorporates a fishing framework to emulate APTs' use of phishing emails as an initial attack vector. This framework allows organizations to send emails with malicious attachments or links to target users. By replicating the behavior of APTs, Copycat enables organizations to assess their email security defenses and evaluate the effectiveness of their detection capabilities.

10.2 The Keylogger Tool

Copycat includes a keylogger tool that aids in APT emulation by capturing and recording keystrokes made by users. This tool mimics the behavior of real-world APTs, allowing organizations to assess their defenses against keylogging attacks. By leveraging the keylogger tool, Copycat enhances the detection and response capabilities of organizations during purple teaming exercises.

10.3 The ImplantF Module

The ImplantF module in Copycat facilitates the manipulation of files and extraction of IOCs. This module enables the creation, update, and deletion of registry keys, helping organizations emulate APT actions targeting registry manipulation. By incorporating the ImplantF module, Copycat enhances its functionality and provides organizations with the means to assess their defenses against advanced threats.

10.4 The Registry Manipulation Module

Copycat also includes a module dedicated to registry manipulation. This module allows organizations to add, update, and delete registry keys on target systems. By leveraging this module, Copycat facilitates accurate replication of APT actions and enables organizations to assess their detection and response capabilities against registry-Based attacks.

Conclusion

In this article, we have explored the concept of purple teaming and the challenges it presents in assessing an organization's security defenses. We have discussed the role of Copycat in purple teaming exercises, emphasizing its capability to accurately emulate APT actions and enhance the overall effectiveness of such exercises. We have examined the components of Copycat's C2 infrastructure, delved into the architectural aspects of Copycat, and outlined the process of building a Copycat C2 framework. Additionally, we have highlighted the importance of APT research, outlined the supported APT profiles in Copycat, and explored the custom modules incorporated into the tool. By leveraging Copycat, organizations can conduct effective purple teaming exercises and improve their security posture against advanced threats.