How to Conduct a Threat Hunt – 10 Steps

Introduction

An overwhelming increase in sophisticated and targeted attacks from threat actors, or even nation-states such as Iran, China and Russia, have made threat-hunting services necessary for organizations and even governments to stay one step ahead of threats.

Adversaries try their level best to perform reconnaissance with hopes of penetrating corporate networks and exploiting systems without detection. In response, organizations require a proactive and iterative threat-hunting program that should be ranked highly for precision and sophistication. In this article, we will explore ten steps covering how to conduct such an effective and reliable threat-hunting campaign.

1. Decide Whether to Choose In-House or Outsourced

When your company decides to conduct a threat-hunting program, it has two options — either in-house or outsourced. In-house threat hunting involves threat hunters from within the organization without hiring the services of a third-party or outsourcer. In this situation, the company should possess a sufficient talent pool to conduct a threat hunt itself. For example, your own threat-hunting team should have the ability to deal with Advanced Persistent Threats (APTs) carried out by adversaries.

On the other hand, if your company doesn’t have enough security staff and resources to conduct a threat hunt, then it will look towards outsourcing the threat-hunting program. In fact, outsourcing is the agreement whereby one organization hires another organization to get its specific tasks or projects done. In the case of threat hunting, one company will hire threat hunters from another company on an ad-hoc basis. These outsourced threat hunters will remain associated with the company until a threat-hunting program is completed successfully.

2. Start With Proper Planning

Whether you start threat hunting in-house or outsourced, the best threat-hunting campaign begins with proper planning. You must plan which processes will be executed to conduct your threat-hunting program. These processes are designed to discern not only what you have, but also the data sources that are misconfigured or missing. You cannot secure what you do not know exists!

3. Establish and Test Hypothesis

Next, analysts must develop a hypothesis by identifying the results they expect from the hunting campaign. For example, if they are conducting a hunt against fileless malware, the hunt’s aim is to find adversaries who are launching attacks by employing tools such as WMI and PowerShell.

A fileless malware or fileless infection is malicious coding that exists only in memory rather than on the hard drive of the targeted system. It is written directly to Random Access Memory (RAM). Attackers use attacking tools such as PowerShell to carry out this fileless malware. PowerShell and WMI include powerful scripting language that delivers deep access into a system’s inner core, including unrestricted access to the Windows APIs.

Testing every PowerShell process can be a time-consuming, frustrating and daunting task. Therefore, analysts should make smart choices and collect only that information which provides meaningful outcomes. The analysts should develop a wise approach to test the hypothesis without reviewing every event.

4. Gather Data

Data gathering is a vital process that involves the collection, normalization, and analysis of critical data. However, identifying what should be logged can be a Gordian knot. The easiest and most reliable way to formulate your own logging strategy is to follow already-existing standards, including NIST and OWASP. Collecting all types of logs is not a prudent approach, as it is a time-consuming process that further creates annoying and pesky noise.

The following logs are recommended to collect for your threat hunting campaign.

• Network infrastructure logs (e.g., load balancer, firewall, router, VPN)
• Host-based logs (e.g., endpoint detection response, operating systems)
• Virtual machine hypervisor
• Antivirus
• Host/network IPS/IDS
• Host-based logs
• Database application and transaction
• Application firewall
• Domain Name Service (DNS)
• Active Directory/LDAP
• Proxy
• Application and Web server
• DHCP
• Service logs
• Configuration Management Database (CMDB)

Data should also be collected from some other internal sources, including past incidents, threats to your employees’ intellectual property, threats to your particular line of business and industry verticals, and reconnaissance attempts in the face of your infrastructure. External sources may include paid intelligence feeds, a partnership with government agencies and Open-Source Intelligence (OSINT).

Data retention is the essential component of any logging policy. Data retention determines the quantity and the validity of data for a certain span of time.

5. Organize Data

Once the data is collected and compiled properly, hunters need to identify which hunting tools they are going to utilize for organizing and analyzing this information. For this to be done effectively, various tools are available, including reporting tools in Security Information and Event Management (SIEM), buying analytical tools or employing Excel to sort data or create pivot tables. After that, this organized data can provide meaningful results to the analysts.

6. Automate Your Routine Tasks

Some security analysts consider automation inappropriate for the hunt. According to Anton Chuvakin, a Gartner research vice president, threat hunting is and ought to be human analyst-centric, not tool-centric. He believes that the hunt needs manpower to pursue threats proactively. Unlike automation through machines, manpower has the capability to anticipate an adversary’s move or potential attacks. Nevertheless, we cannot underestimate the importance of automation in threat hunting. By using automation tools to automate some repetitive or routine tasks, we can free up valuable analyst time for more pressing duties.

In some circumstances, the organization does not have enough analysts to proactively hunt down advanced threats. But what if it could teach machines to hunt? In this case, we would use human analysts to fine-tune and train automation processes. Automation tools can be programmed to look for an anomalous event and check whether that event involves the Indicators of Compromise (IoC) or Indicators of Threats (IoT).

Automation mainly addresses three challenges, including:

• Automate Data Enrichment: An automation tool can assist with enriching data by performing root-cause analysis and automatically clustering similar events together
• Automate Factor Identification: Machine learning has the ability to identify factors that bear analysis, either through discovery performed by the automation tool or through clear labeling provided by analysts
• Automate Event Analysis: A good automation tool can quickly analyze millions or billions of events

7. Containing and Responding to Cybersecurity Threats and Vulnerabilities

At this point, analysts should now have enough data to answer their hypothesis. With the information in hand, there are two types of possibilities: either the vulnerability is found, or the actual threat is detected. In either case, the analysts will have to take an immediate action.

If the vulnerability is found, the analysts should resolve it. On the other hand, if the actual threat is identified, then the incident response team should contain a threat and perform the remediation process. However, the third possibility may exist that neither vulnerability nor threat is found. In this scenario, no action is needed, as a security posture is not compromised.

8.   Final Action

At this crucial stage, threat hunters define their course of action. For example, what resources are available to contain detected threats or vulnerabilities? How much time is required to eliminate a threat altogether and prevent it from becoming a nightmare? This process usually involves remediation, which puts the responsibility on the incident response team. Most often, threat hunters cede their responsibility in the remediation phase.

9. Documenting and Reporting to Stakeholders

Documentation of any detected vulnerabilities or threats is also a crucial part of the threat-hunting campaign. As soon as you get to conclusions, you will need to communicate to stakeholders, such as information security management, about the result of the process. Prepare a clear document informing stakeholders of the risk level criteria employed for the assessment, including the crucial factors employed for the threat assessment. At the same time, try to perform documentation on all the identified IoCs and sources.

Documented data will retain all the results drawn from the previous threat-hunting efforts. This data can be helpful to trace the history of attacks and verify whether the current attack is repeating or a new one.

10. Learned Lessons: A Continuous Improvement Cycle

It is rightly said that “anticipation is better than realization.” From a threat-hunting perspective, it’s better to anticipate threats than to realize and react to them once your antivirus program or SIEM raises an alert. Being proactive requires threat hunters to understand the entire IT infrastructure, including systems, applications and networks. To this end, threat hunters must obtain proper training from a reliable institution.

Now that the intrusion has been neutralized, identify the porous areas that threat actors capitalized on to penetrate the network. Learn how similar types of weaknesses and vulnerabilities could be prevented in the short or long term.

Conclusion

It’s plain to see that threat hunting involves complex methods that can certainly help in detecting and responding to the cyberattacks. Though there is no globally accepted standard for threat hunting, companies have devised their own plans and strategies to conduct a threat hunting. In this article, you have learned the most common techniques that organizations use to conduct threat hunting program proactively and iteratively.

Sources

1. Logging Cheat Sheet, OWASP
2. Guide to Computer Security Log Management, NIST
3. How to automate threat hunting, CSO
4. The Hunter’s Handbook, Endgame
5. Is threat hunting the next step for modern SOCs?, SearchSecurity
6. Huntpedia: Your Threat Hunting Knowledge Compendium, Sqrrl
7. What you need to know about PowerShell attacks, Cybereason

Be Safe

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Fakhar
Imam

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