The Importance of Network Data to Threat Hunting (Part 1)

Original Entry by : Robert Salier

Introduction to Threat Hunting

By Robert Salier, Product Manager, Endace

Robert Salier, Product Manager, EndaceCriminal hackers are stealthy. They put huge efforts into infiltrating without triggering intrusion detection systems or leaving traces in logs and metadata … and often succeed. So you need to actively go searching for them. That’s why SecOps teams are increasingly embracing threat hunting.

This is the first in a series of blog articles where we discuss various aspects of threat hunting, and how visibility into network traffic can increase the efficiency and effectiveness of threat hunting. This visibility is often the difference between detecting an intruder, or not, and collecting the conclusive evidence you need to respond to an attack, or not.

In December 2015 Ukraine suffered from a power grid cyber attack that disrupted power distribution to the nation’s citizens. Thirty substations were switched off and damaged leaving 230,000 without power.

This attack was meticulously planned and executed, with the attackers having first gained access over six months before they finally triggered the outage. There were many stages of intrusion and attack, leaving traces that were only identified in subsequent investigations. Well planned and executed threat hunting would probably have uncovered this intruder activity, and averted the serious outages that took place.

This is a good example of why, in the last few years, threat hunting has been gaining substantial momentum and focus amongst SecOps teams, with increasing efforts to better define and formalize it as a discipline. You’ll see a range of definitions with slightly different perspectives, but the following captures the essence of Threat Hunting:

The process of proactively and iteratively searching through IT infrastructure to detect and isolate advanced threats that evade existing security solutions.

There’s also some divergence in approaches to threat hunting, and in the aspects that individual organizations consider most important, but key themes are:

  • To augment automated detection, increasing the likelihood that threats will be detected.
  • To provide insight into attackers’ Tactics, Techniques and Procedures (TTP’s) and hence inform an organization where they should focus their resources and attention.
  • To identify if, and where, automated systems need updating – e.g. with new triggers.

So, threat hunting involves proactively seeking out attacks on your IT infrastructure that are not detected by automated systems such as Intrusion Detection Systems (IDSs), firewalls, Data Leakage Prevention (DLP) and Endpoint Detection and Response (EDR) solutions. It’s distinct from incident response, which is reactive. It may, however, result in an incident response being triggered.

Although threat hunting can be assisted by machine-based tools, it is fundamentally an activity performed by people, not machines, heavily leveraging human intelligence, wisdom and experience.

In the next article, we explore how leading organizations approach threat hunting, and the various data, resources, systems, and processes required to threat hunt effectively and efficiently.

In the meantime, feel free to browse the Useful References page in our Theat Hunting Section on, which contains both a glossary and useful links to various pages related to threat hunting. Below are some additional useful references.


(1) Threat Hunting Report (Cyber Security Insiders), p22

(2) 2018 Threat Hunting Survey Results (SANS), p13

(3) 2018 Threat Hunting Survey Results (SANS), p5

(4) Improving the Effectiveness of the Security Operations Center (Ponemon Institute), p10

(5) The Ultimate Guide To Threat Hunting, InfoSec Institute