What Is Threat Hunting: Understanding Proactive Cybersecurity

Traditional security measures like firewalls, intrusion detection systems, and antivirus software are essential components of a layered defense strategy. However, they may not always be effective against advanced threats or targeted attacks. That’s where cyber threat hunting comes in to complement existing security measures. 

In our article, we will take a closer look at the concept of threat hunting and explore its processes, methodologies, and challenges that threat hunters may face.

What is threat hunting?

Threat hunting, or cyber threat hunting, is a proactive cybersecurity practice where skilled professionals search for potential threats or security breaches within an organization’s network. 

While automated security systems provide solid protection, they are not all-powerful. Sophisticated malicious actors can slip through the defenses and remain undetected in a network for extended periods, sometimes even months. 

Threat hunting involves human analysts who actively seek out signs of malicious activities that might have evaded automated defenses. These specialists are called threat hunters, as their main objective is to identify and neutralize potential threats before they can cause significant damage. 

For instance, let’s say a threat hunter notices unusual activity in the company’s network, like a sudden surge in data transfers late at night when no one should be working. This could be a sign of a potential data breach or unauthorized access. By spotting these anomalies early on, threat hunters can investigate further, prevent potential harm, and strengthen the company’s defenses.

Threat hunting is usually performed by:

• In-house security teams. Larger organizations may have dedicated threat hunting teams within their cybersecurity departments.
• Security Operations Centers (SOCs). These teams often include threat hunting as part of their broader monitoring and incident response activities.
• Managed Security Service Providers (MSSPs). External providers that offer threat hunting as one of their services.
• Freelance contractors and consultants. Independent professionals or firms that specialize in threat hunting and can be hired on a contract basis.

Threat hunters are typically employed by large organizations with over 1,000 employees. They are responsible for identifying new threats and closely collaborating with the SOC team and cybersecurity manager to ensure effective incident response and mitigation strategies.

Small or medium-sized businesses often opt to outsource threat hunting services due to the high cost of maintaining an in-house specialist. For instance, in the USA, salaries for experienced threat hunters can range from $118,000 to $195,000 per year per person, depending on location and expertise.

In some cases, cybersecurity analysts within the organization may also perform the threat hunting job.  

How threat hunting works 

Threat hunters utilize various techniques, tools, and methodologies to collect and analyze data, looking for signs of compromise and indicators of suspicious activities. They also collect and analyze threat intelligence, which includes information about attempted or successful intrusions, known attack patterns, and indicators of compromise (IOCs). This intelligence helps guide the hunting process and provides insights into attackers’ latest tactics, techniques, and procedures (TTPs). 

The process of proactive threat hunting cyber security typically involves three stages: trigger, investigation, and resolution.

The trigger

The journey of threat hunting commences with the identification of triggers that hint at the presence of potential threats within an organization’s network. These triggers can take various forms, such as anomalies, unusual patterns, or suspicious activities that deviate from established norms. 

For instance, in 2017, Equifax, one of the largest credit reporting agencies in the United States, suffered a significant data breach that exposed the personal information of approximately 147 million individuals. They detected the cyberattack by identifying anomalies and suspicious activities within their network. Equifax’s security team noticed unusual network traffic patterns and abnormal queries to their databases. These activities deviated from established norms and raised suspicions.

Investigation 

Once the triggers have been identified, the next crucial step is to conduct a thorough investigation and analysis to uncover the underlying causes and potential implications. This involves using advanced security tools, threat intelligence, and forensic techniques to examine unusual activities and determine their nature. Additionally, it requires correlating data points and exploring potential attack vectors to gain a comprehensive understanding of the threat landscape. This process helps to uncover layers of suspicion and determine the best approach to address the problem.

Resolution

Once the investigative phase is complete and actionable insights have been gathered, the next step is to develop an effective resolution strategy. This plan should include immediate actions to halt the threats and bolster the organization’s defenses by addressing vulnerabilities, revising security policies, and taking proactive measures to prevent similar threats in the future. 

Types of threat hunting

Cyber threat hunting strategies typically fall into one of these three classifications:

• Structured. In structured hunting, threat hunters analyze indicators of attack (IoA) and identify suspicious tactics, techniques, and procedures (TTPs). They start by formulating a hypothesis about the attacker’s methods based on a thorough examination of log data and other relevant sources to find the traces of the attack and neutralize the malicious actor. 
• Unstructured. In an unstructured hunt, the cyber threat hunter initiates the search from a specific indicator of compromise (IoC). They then start to investigate historical data, searching for patterns and clues about the threat. This approach may also help uncover previously undetected threats that may still pose a risk to the organization.
• Situational. Situational threat hunting focuses on high-risk events, entities, or situations (such as a recent security incident or a known vulnerability) specific to the organization. Threat hunters utilize threat intelligence, relevant data, and contextual information about network entities to identify potential threats or vulnerabilities.

Threat hunting methodologies

Although having dedicated threat hunters may be difficult for some companies, security teams can utilize threat hunting techniques to strengthen their defense mechanisms and stay ahead of cyber attackers. Let’s explore some of the notable methodologies:

Hunting based on intelligence  

This approach relies on threat intelligence to guide the hunting process. Threat intelligence provides information about known threats and attacker TTPs, which security specialists can use to proactively search for similar indicators within an organization’s environment. For example, if threat intelligence reports indicate a rise in phishing attacks targeting a specific industry using a particular malware variant, intelligence-driven hunting would involve searching for signs of this specific threat within the organization’s network logs and endpoints.

Investigation driven by hypotheses

In this method, threat hunters formulate hypotheses or educated guesses about potential threats based on available data, trends, or security events. They then conduct targeted investigations to validate or refute these hypotheses. For instance, a hypothesis could be that an increase in failed login attempts during off-hours may indicate an insider threat attempting unauthorized access. To confirm or reject this hypothesis, threat hunters would investigate login logs and user behavior.

Investigation using indicators of attack (IoA)

Indicators of attack (IoA) are patterns or activities that suggest malicious behavior or an ongoing attack. Threat hunters use IoAs derived from threat intelligence, security research, or historical incidents to search for similar indicators within their organization’s systems. For example, an IoA could be a series of network connections to known malicious IP addresses associated with command-and-control servers. Threat hunters would monitor network traffic logs to identify and block these suspicious connections.

Hybrid hunting

Hybrid hunting combines multiple threat hunting methodologies, tools, and data sources to maximize effectiveness. It integrates intelligence-driven approaches, hypothesis-driven investigations, IoA analysis, and advanced analytics to provide comprehensive threat detection and response capabilities. For example, threat hunters may use threat intelligence to identify emerging threats, formulate hypotheses based on this intelligence, investigate IoAs related to known attack vectors, and apply machine learning models to detect novel threats or abnormal behaviors.

Threat hunting tools 

Threat hunting tools are software applications and platforms designed to assist security teams in proactively identifying and investigating potential cybersecurity threats within an organization’s network and systems. These tools often incorporate advanced analytics, machine learning, threat intelligence integration, and automation capabilities to enhance threat detection and response efforts. 

Here are some common types of threat hunting solutions and tools:

• SIEM (Security Information and Event Management) systems. SIEM tools collect, aggregate, and analyze security data from various sources such as network devices, servers, endpoints, and applications. They provide real-time monitoring, correlation of events, and alerting capabilities to identify potential threats.
• Endpoint detection and response (EDR) tools. EDR solutions focus on monitoring and analyzing activities on endpoints (e.g., workstations, servers) to detect suspicious behavior, malware, and unauthorized activities. They offer features like threat hunting queries, forensic analysis, and incident response automation.
• Threat intelligence platforms. These platforms integrate external threat intelligence feeds, indicators of compromise (IoCs), and contextual information about known threats. They help threat hunters correlate security events with threat intelligence data to identify and prioritize potential threats.
• User and entity behavior analytics (UEBA) solutions. UEBA tools analyze user and entity behaviors across the network to detect abnormal activities, insider threats, and unauthorized access attempts. They use machine learning algorithms to identify patterns and anomalies that may indicate potential security incidents.
• Threat hunting platforms. Dedicated threat hunting platforms offer comprehensive capabilities for proactive threat hunting activities. They provide advanced querying, data visualization, threat hunting playbooks, automated hunting workflows, and collaboration features for effective threat hunting operations.
• Deception technologies. Deception technologies deploy decoys, traps, and lures within the network to deceive and detect attackers. They create false targets and breadcrumbs to divert attackers away from real assets and trigger alerts when attackers interact with the decoys.

Here are some examples of free and open-source threat hunting tools:

• AI Engine. AIEngine is an interactive tool that can update the network’s intrusion detection system. It includes features like packet inspection, DNS domain classification, network forensics, and more. It supports various systems and add-ons.
• APT-Hunter. APT-Hunter is a threat-hunting tool for Windows event logs that can detect suspicious activity and track APT movements. It maps Mitre ATT&CK tactics and techniques to Windows event log event IDs and detects indicators of attack.
• Attacker KB. Attacker KB provides information about vulnerabilities, exploits, and their impact. It helps threat hunters identify and rank vulnerabilities based on their relevance and potential impact.
• Automater. Automater is a tool that analyzes URLs, hashes, and domains to simplify intrusion analysis. It gathers relevant information from well-known sources and can be used to search for IP addresses, MD5 hashes, and domains.
• BotScout. BotScout is a tool that prevents automated web scripts (bots) from filling out forms, spamming, and registering on websites. It tracks bot names, IP addresses, and email addresses and provides a free API for evaluating forms on websites.
• CrowdFMS. CrowdFMS automates the collection and processing of samples from websites that publish information about phishing emails. It triggers alerts when phishing emails reach the network and provides a framework for automating the collection and processing of samples.
• Cuckoo Sandbox. Cuckoo Sandbox is an open-source tool for analyzing malware. It can analyze various malicious files and websites in virtualized environments. It allows for sophisticated memory analysis and has a modular design for customization.
• DeepBlue CLI. DeepBlueCLI is an open-source tool that analyzes security events and logs from Windows systems. It provides command-line capabilities for threat hunting and incident response.

Challenges that threat hunters may face

While this practice is essential for protecting organizations from cyberattacks, it also comes with numerous challenges and considerations that require careful navigation.

Data overload

One major challenge in threat hunting is dealing with a huge amount of data. Organizations receive information from various sources like network logs, endpoint data, and threat intelligence feeds. This flood of data can overwhelm security teams, making it hard to find important irregularities. Sorting through this data to find real threats requires advanced tools and skilled analysts who can tell normal network behavior apart from suspicious activities.

Evolving threats

Cyber threats are always changing, which makes it tough for threat hunters. Attackers constantly update their tactics to avoid detection. Security teams must stay alert, understand new threats, and adjust their hunting methods accordingly to stay ahead.

Skills gap and resource constraints

Creating a strong security team needs people with diverse skills in cybersecurity, data analysis, and IT systems knowledge. However, there’s a shortage of cybersecurity experts, making it hard for organizations to find and keep good threat hunters. Also, limited resources, budget issues, and other priorities can make it difficult to run effective threat hunting programs, leaving organizations vulnerable to advanced cyber threats.

Final thoughts

While threat hunting is essential for cybersecurity, the lack of skilled specialists and the high cost of their services can pose a challenge for many organizations. However, there are cost-effective solutions. Organizations can invest in training existing staff, outsource threat hunting services, or use threat intelligence platforms. Tools like threat hunting content platforms can also bridge the knowledge gap and empower analysts. Even if you haven’t encountered cyber attacks or information leaks yet, it doesn’t mean it can’t happen at all. Therefore, implementing threat hunting as part of your cybersecurity strategy is definitely worth considering.