Building an Effective Threat Hunt Against Nation-State Actors

Introduction

In this special edition of Tech Talk Tuesday, Dan Gunter from Insane Cyber explores a systematic approach to threat hunting, particularly against nation-state actors targeting U.S. defense. The discussion revolves around transforming threat intelligence reports into actionable strategies, using a structured method to identify and mitigate cyber threats.

Step 1: Understanding the Threat Intelligence Report

The first step in any threat hunt is analyzing a threat intelligence report. In this case, the video references a recent CISA (DHS) report detailing threats posed by nation-state actors. While such reports contain useful recommendations, deeper analysis is required to extract actionable insights for defenders.

Step 2: Whiteboarding the Attack Patterns

Using tools like Miro, security teams can break down reports into tactics, techniques, and procedures (TTPs). This involves extracting key details, such as:

• Attack methods (e.g., brute-forcing Microsoft 365 accounts, using phishing emails with shortened URLs).
• Observed attacker behaviors (e.g., credential harvesting, lateral movement techniques).
• Specific network or host-based indicators that can be monitored.

By mapping out these elements, defenders can start developing a clearer picture of how an attack unfolds.

Step 3: Refining the Observables

Once the report is broken down, the next step is identifying key observables—the data points that indicate an attack is occurring. These can include:

• Host-based observables: Logs from Windows Firewall, Active Directory, PowerShell activity.
• Network-based observables: HTTP, DNS traffic, email analysis, and SMB authentication attempts.
• Behavioral indicators: Suspicious patterns such as unauthorized access to sensitive files or unexpected privilege escalations.

One example covered in the video is NTDS.DIT credential harvesting, where attackers extract password data from Active Directory. The MITRE ATT&CK framework is recommended as a powerful reference for understanding these techniques and their variations.

Step 4: Understanding Defensive Limitations

The video emphasizes that defenders must recognize the limits of their monitoring capabilities. For example:

• SMB authentication logs may show who accessed a system, but not the full traffic details.
• Attackers using built-in Windows utilities may not trigger traditional malware alerts.
• Certain forensic artifacts, like temporary file modifications, may be difficult to detect in real-time.

To counteract these limitations, defenders should collect and analyze diverse data sources, including:

• Domain Controller Logs – Critical for tracking authentication attempts and suspicious privilege escalations.
• Cloud Service Logs – Essential for detecting unauthorized access in environments like AWS or Azure.
• Memory & Disk Analysis – Advanced forensic techniques for uncovering stealthy attacker activities.

Step 5: Community Collaboration and Continuous Improvement

A key takeaway from the video is that defenders have strength in numbers. By sharing insights, tactics, and threat-hunting methodologies, security teams can collectively outmaneuver even the most sophisticated adversaries. The speaker encourages engagement on social media (#threathunting) and participation in collaborative efforts, such as a shared Miro board where defenders can contribute to and refine their methodologies.

Conclusion: Defenders Have the Power

While nation-state attackers have significant resources, they cannot fully hide their tracks. By following a structured approach—whiteboarding attack patterns, refining observables, understanding defensive limitations, and collaborating with the community—defenders can proactively identify and mitigate cyber threats.

This video serves as both a guide and a call to action: Threat hunting is not just about technical skills, but also about leveraging collective knowledge and constantly evolving defenses to stay ahead of attackers.