Proofs of Concept: A Proactive Approach for Hypothesis-Driven Threat Hunting | by Renae Kang | Oct, 2024

In today’s evolving threat landscape, traditional reactive approaches to cybersecurity are no longer enough to protect organizations from sophisticated attacks. Threat hunting fills this gap with a proactive, methodical strategy for uncovering threats that evade automated defenses.

At the heart of effective threat hunting is hypothesis testing — the practice of developing informed assumptions about potential threats and systematically investigating them. A powerful tool in this process is the Proof of Concept (POC), which helps validate hypotheses, simulate attack scenarios, and refine detection mechanisms. By leveraging POCs, organizations can test their assumptions in controlled environments, enhancing their detection capabilities and mitigating potential threats.

In this blog, we’ll discuss how Adobe Security’s threat hunting team employs strategies such as hypothesis testing and POCs to strengthen our detection capabilities and proactively defend against evolving threats.

In threat hunting, there are two primary approaches: defensive and offensive.

Defensive Approach

In a defensive approach to threat hunting, proactive hunting plays a critical role. Rather than waiting for alerts or known incidents, threat hunters actively search their systems, networks, and logs for traces of malicious activity, with a goal of identifying Indicators of Compromise (IoCs) or Tactics, Techniques, and Procedures (TTPs) described in threat intelligence reports.

Additionally, threat hunters use behavioral patterns and anomalies from these reports to detect signs of advanced or stealthy threats that may bypass traditional signature-based detection systems. This proactive strategy enables hunters to identify latent threats that may exist within the environment without triggering automated alerts, ensuring a more comprehensive and preemptive defense against potential attacks.

Offensive Approach

In an offensive approach to threat hunting, the hunter takes on the mindset and tactics of an attacker to simulate real-world cyber threats. This involves using the same Tactics, Techniques, and Procedures (TTPs), as well as tools commonly employed by attackers. Threat hunters may also develop custom tools that don’t yet have detection signatures, enabling them to emulate more sophisticated or novel attacks.

By mimicking an attacker’s steps to target the organization’s internal infrastructure, threat hunters can generate valuable artifacts, such as logs or traces of malicious activity, which help security teams identify similar actions in the future and detect actual attacks early. This process also helps uncover gaps in existing detection systems or logging mechanisms, enabling teams to strengthen defenses and improve overall security monitoring.

Weighing these two approaches, Adobe’s threat hunting program integrates both strategies into a comprehensive framework. Traditional reactive defensive methods often fall short against modern adversaries, so we incorporated a range of offensive techniques during our testing phase that mimic the tactics a malicious actor might employ. This strategy allows us not only to validate hypotheses but also to produce the artifacts necessary for developing logic behind potential detection rules.

Threat hunting is often driven by hypotheses — educated guesses based on known attack patterns, anomalies, or intelligence that suggest the presence of a threat. Rather than waiting for threat alerts to trigger, threat hunters proactively search for indicators of compromise (IOCs) or suspicious activities within their networks. A hypothesis can stem from various sources, including recent threat intelligence reports, unusual network behavior, known vulnerabilities within the organization’s environment, or legitimate software that may be exploited for malicious purposes.

For instance, a hypothesis might suggest the presence of a specific type of malware targeting specific assets or data within a system. By leveraging such hypotheses, Adobe has not only identified novel techniques but also uncovered critical vulnerabilities that emerged during the testing process.

In the context of threat hunting, POC involves creating a controlled, often isolated environment to test a hypothesis by simulating a potential threat scenario, observing its behavior, and assessing whether it can be detected and mitigated. Running a POC allows threat hunters to transition from theoretical assumptions to concrete evidence, enabling them to refine their detection and response strategies.

This process offers several defensive advantages, including generating valuable indicators, validating existing detection rules, creating high-fidelity detection rules, identifying visibility gaps, and, in some cases, facilitating the capture of attackers.

POCs are essential in threat hunting for the following reasons:

• Validation of Hypotheses: POCs provide a structured way to test hypotheses, allowing organizations to verify whether a suspected threat is real or benign. This reduces the chances of false positives and helps to focus resources on real threats.
• Enhanced Detection Capabilities: POCs observe the behavior of a simulated threat in a testing environment, allowing threat hunters to refine their detection techniques by adjusting alert thresholds, fine-tuning detection rules, or developing new monitoring strategies.
• Risk Reduction: Organizations can observe potential threats in a controlled environment through POCs, allowing for safe experimentation with various scenarios and responses while minimizing risk to the broader network.
• Improved Incident Response: POCs provide insights during testing that directly inform incident response strategies, enabling organizations to understand how threats manifest and spread, which help drive more effective containment and remediation plans.
• Knowledge Transfer and Skill Development: POCs help upskill threat hunting teams by offering hands-on experience with real-world scenarios, improving their understanding of the nuances of threat detection and response.
• Tool Validation: POCs enable the evaluation of tools within the security stack and assess their capabilities.
• Visibility Gaps: POCs help identify instances where threat hunters may encounter gaps in log sources, logging capabilities, and coverage while implementing techniques to validate hypotheses.

Integrating POCs into threat-hunting efforts is not just a best practice; it has become essential in today’s complex threat landscape. By validating hypotheses through meticulously designed assessments, POCs can enhance detection capabilities, minimize the risk of false positives, and strengthen an organization’s overall cybersecurity posture. As threats continue to evolve, the ability to test and refine our defenses through POCs will be a critical differentiator in staying ahead of potential attackers.