What is Threat Hunting?

Cyber Fusion

Posted on: November 22, 2021

It is not wise for even the most capable and resourceful security teams to consider their cyber defenses as impervious. As an organization, you have to be prepared for all kinds of cyber threats. Security personnel must always remain vigilant for the next potential threat and vulnerabilities. This is where cyber threat hunting comes into action.

Threat Hunting

Instead of sitting idle and waiting for threats to result in attacks, cyber threat hunting allows the proactive searching for threats that lay undetected. The search spans from networks to datasets, and endpoints based on hypotheses formed on the behaviors of threat actors and verifying the hypotheses through active searchers. Threat hunting brings human creativity and environmental context together, along with deeper forensics and reasoning.

Threat Hunting Modus Operandi

It is presumed that threat actors are already hiding inside a network and thus, threat hunters start investigating the probable presence of malicious activity. The investigation can be conducted with the following methodologies.

Hypothesis-driven threat hunting

The hypothesis-driven investigation is a proactive methodology that starts with the creation of an actionable, realistic hypothesis by a human analyst. This is followed by the execution and testing of the hypothesis. The hypothesis should be based on observations from real-world data, intelligence, and insights based on prior experiences in order to make it actionable. Analysts can leverage the MITRE ATT&CK framework and employs playbooks to detect Advanced Persistent Threat (APT) groups or any other malicious presence on their networks. The huge pool of crowdsourced data enables threat hunters to gain insights into the threat actor behavior.

Intel-driven threat hunting

This is a threat hunting approach that leverages Indicators of Compromise (IOCs) and the Tactics, Techniques, and Procedures (TTPs) used by threat actors through tactical threat intelligence. Security analysts can hunt for specific threat indicators before and after receiving an alert to identify any compromise in the environment that could have gone unnoticed by existing security controls. Using security automation and orchestration, security teams can establish the automated flow of alerts from various sources using STIX and TAXII to employ this threat intelligence for threat hunts.

Threat Hunting Techniques

Searching

Threat hunts are initiated by questioning indicative data, such as flow records, alerts, logs, memory dumps, and digital images for particular samples using well-defined search criteria. Since it is uncommon to know what exactly to look for, threat hunters form a hypothesis about the contextual threats and how to find them.

Clustering

When similar data points are collated based on specific characteristics, it is known as clustering. This provides security analysts with a broader picture of the data to be prioritized and correlated, and ultimately, interweaving them to gain clear insights into the network.

Grouping

This step consists of searching for a precise cluster of items that have been classified as suspicious.

Stacking

Stack counting or stacking involves taking a count of the number of occurrences of a specific data type and evaluating the deviances. It is most effective when the data sets produce a finite number of results.

Why do You Need Threat Hunting?

Threat hunting is a crucial element of a proactive cyber defense strategy as sophisticated threats can bypass traditional defenses. Malware today can evade detection by antivirus and attackers are growing tremendously sophisticated with every passing day. It is not feasible for organizations to wait for days and weeks on end to detect incidents.

Threat hunting is mostly human-driven, systematic, and continual, thus, ensuring effective damage control and reduced risks to organizations. As threat hunting is of a proactive nature, it enables analysts to respond to an incident more quickly than otherwise conceivable.

Conclusion

The efficacy of threat hunting depends on the analysts’ capabilities integrated with quality tools. The quicker an organization detects active threats and communicates to an incident responder, the quicker the threat will be contained with less damage to the networks and systems. As cyber threats are a persistent nuisance, it is crucial that organizations implement threat hunting programs and defend against potential attacks.