How Does Threat Hunting Work?
Cyber threat hunting involves a combination of advanced technology and skilled analysts to search for signs of malicious activity within an organisation’s network. This proactive approach goes beyond traditional security measures by actively seeking out threats that might have evaded automated detection systems. Let’s explore the detailed mechanics of how threat hunting works.
Step-by-Step Process of Threat Hunting
- Hypothesis-Driven Investigation: Threat hunting begins with a hypothesis. This hypothesis is based on threat intelligence, known attack vectors, and an understanding of the organisation’s network and its vulnerabilities. For instance, a threat hunter might hypothesise that an attacker could exploit a specific type of software vulnerability recently reported in the industry.
- Data Collection and Analysis: Once a hypothesis is established, threat hunters collect and analyse vast amounts of data from various sources within the network. This includes logs from firewalls, intrusion detection systems (IDS), endpoint detection and response (EDR) tools, and other network devices. For example, during the investigation of the 2023 attack on Uber, threat hunters extensively analysed network traffic logs to identify unusual patterns indicative of a breach.
- Detection Techniques: Threat hunters employ a range of detection techniques to identify anomalies and potential threats. These techniques include:
- Anomaly Detection: Identifying deviations from normal network behaviour.
- Signature-Based Detection: Matching known threat signatures with observed data.
- Behavioural Analysis: Analysing the behaviour of users and systems to detect suspicious activities.
- Threat Intelligence: Using external and internal threat intelligence to inform hunting activities and validate findings.
- Response and Mitigation: Once a potential threat is identified, immediate actions are taken to contain and mitigate it. This may involve isolating affected systems, blocking malicious IP addresses, and removing malware. For instance, in the 2022 Microsoft Exchange Server attacks, prompt detection and response by threat hunters helped organisations mitigate the impact of the zero-day vulnerabilities exploited by attackers.
Key Tools and Technologies in Threat Hunting
Effective threat hunting relies on a suite of specialised tools and technologies that enable thorough data analysis and threat detection. These tools include:
- SIEM (Security Information and Event Management) Systems: SIEM systems aggregate and analyse log data from various sources, providing a centralised view of network activity. They help threat hunters identify patterns and anomalies indicative of malicious activity.
- EDR (Endpoint Detection and Response) Tools: EDR tools monitor endpoint activities and provide detailed insights into potential threats. They enable threat hunters to detect and investigate suspicious behaviour on individual devices.
- Network Traffic Analysis Tools: These tools analyse network traffic to identify unusual patterns, such as unexpected data exfiltration or communication with known malicious IP addresses.
- Threat Intelligence Platforms: These platforms provide contextual information about threats, including indicators of compromise (IOCs) and indicators of attack (IOAs). They help threat hunters validate findings and understand the tactics, techniques, and procedures (TTPs) used by attackers.
The Role of the Hunter
A successful threat hunter must possess a diverse skill set and deep understanding of cybersecurity principles. Key skills include:
- Log Analysis and Use of Analytics Tools: Threat hunters must be proficient in analysing logs from various network devices to identify signs of compromise.
- Knowledge of Baseline Network Activity: Understanding normal network behaviour is crucial for detecting anomalies. Threat hunters continuously refine their knowledge of what constitutes normal activity to minimise false positives.
- Threat Analysis and Use of Threat Intelligence: Threat hunters need to be well-versed in the latest threat intelligence and capable of analysing the behavioural attributes of network users to detect advanced threats.
- Understanding of Baseline Endpoint Apps, Users, and Access: Since many cyberattacks originate at endpoints, threat hunters must be adept at analysing endpoint data to quickly identify and respond to incidents.
Case Study: Proactive Threat Hunting in Action
In 2022, a major financial institution implemented a comprehensive threat hunting program that uncovered a sophisticated phishing campaign targeting its employees. The threat hunters hypothesised that attackers might use spear-phishing emails to gain initial access. By analysing email logs and user behaviour, they identified several compromised accounts. Further investigation revealed that the attackers were using these accounts to move laterally within the network, aiming to access sensitive financial data. Prompt detection and response by the threat hunting team helped mitigate the threat before any significant data exfiltration occurred.
Integration with Blue Teaming
Threat hunting should not operate in isolation but be closely integrated with the broader security operations centre (SOC). This integration ensures that insights and findings from threat hunts are utilised to enhance the overall security posture. Blue teams, responsible for defending the organisation, benefit from the proactive insights provided by threat hunters, allowing them to refine detection and prevention strategies.
For example, during the SolarWinds attack in 2023, the collaboration between threat hunters and blue teams was crucial in identifying the presence of the SUNBURST malware. Threat hunters’ proactive efforts to search for signs of the malware led to the discovery of indicators of compromise, which were then used by blue teams to enhance their detection capabilities and prevent further infiltration.
The mechanics of threat hunting involves a meticulous and proactive approach to uncovering hidden threats within an organisation’s network. By combining advanced tools, skilled analysts, and integration with blue teaming efforts, organisations can significantly enhance their ability to detect and mitigate cyber threats.