What is Digital Forensics and Incident Response (DFIR)? 

DFIR is the process of collecting digital forensic evidence, hunting for suspicious activities, and continuously monitoring for endpoint events. Going a bit more in-depth, security expert Scott J. Roberts defines DFIR as "a multidisciplinary profession that focuses on identifying, investigating, and remediating computer-network exploitation."

From a process standpoint, an incident response and investigation plan that leverages comprehensive forensics will include responsibilities such as investigation, analysis management, threat detection, communications, and documentation of findings.

Subsequent remediation and cleanup typically includes removing attacker remote-access capabilities, restoring prioritized business processes and systems, and securing compromised user accounts.

Contained in the minutiae of those processes are the following key components of a DFIR framework:

  • Muti-system forensics: One of the hallmarks of DFIR is the ability to monitor and query all critical systems and asset types for indications of foul play. 
  • Attack intelligence: Spotting suspicious network activity means knowing what to look for. This means developing the ability to think like an attacker, not only to remediate vulnerabilities in your own systems, but also to spot signs of exploitation. 
  • Endpoint visibility: Security teams need visibility into corporate networks and the seemingly endless complex system of endpoints — then they need a way to clearly organize and interpret data gathered from them.

The Role of DFIR in Cybersecurity

Within the larger framework of cybersecurity practices, DFIR serves to obtain a finely detailed look at how a breach occurred and the specific steps it will take to remediate that particular incident. Let’s dive deeper into the separate functions that make up a holistic DFIR practice.

Incident Detection and Response 

Detecting compromised users affected by a breach is the first step to gaining visibility into what occurred and crafting a timely response to ensure attackers are purged from the network, the breach contained and fixed, and any remaining exploitable vulnerabilities remediated. From there, a thoughtful investigation can take place, one that can identify evolving attacker behavior and more accurately spot it in the future.

Forensic Investigation

An investigation into a specific breach is never going to look like the investigation that came before it. It’s imperative to customize a situational approach to a threat, whether that threat is impending or has already taken place. When launching an investigation, a security team might perform data analysis on the affected asset(s), acquiring browser-history artifacts, event logs, files from directories, and registry hives.

Threat Intelligence and Analysis

The most critical step in gathering threat intelligence is ensuring the data are tailored to each and every function in a security organization. Once put into practice, the intelligence cycle will produce results by collecting, analyzing, and disseminating to relevant stakeholders in the organization. This process presupposes a heavy emphasis on automated analysis that can quickly search through data and surface relevant insights.

Malware Analysis and Reverse Engineering

In the analysis of potential malware on a network, a security team would submit a suspicious sample, run it through a chain of analyzers, and then classify the threat based on risk score. This can help to prioritize the situation. Is it something that needs immediate attention or can it wait? In this analysis period, reverse engineering malware can help teams find the best way to understand its ultimate target and quickly eradicate it.

Incident Containment and Recovery

Once a breach has been fully scoped and the affected assets, applications, and users have been contained, a security operations center (SOC) will launch a predetermined plan to restore normal business operating processes. Documentation is key to disaster planning so teams can understand the various components of the backup system. Maintaining an automated, offline backup can further help the process of recovering from a malware attack.

How is Digital Forensics Used in Incident Response? 

Digital forensics is used in incident response by becoming embedded in the process. As every security professional knows, it’s not enough to respond to incidents and fix the issue, you have to know exactly what happened and how it happened so that systems can be calibrated for that attack path and surface customized alerts the next time that behavior is spotted.

If someone were to ask, ”what are digital forensics?”, we would more pointedly want to have a discussion on multi-system forensics (briefly mentioned above). That is, the ability to monitor and query critical systems and asset types all along a network for indications of suspicious behavior. Let’s take a more granular look into what that process entails:

  • Collect: Perform targeted collections of digital forensic evidence across endpoints.
  • Monitor: Continuously monitor for endpoint events like logs, file modifications, and process execution. 
  • Hunt: Find and access a reliable library of forensic artifacts and search for suspected malware-related activities on your network, customizing to specific threat-hunting needs as you go.

Digital forensics should enable threat responders and hunters to collect, query, and monitor almost any aspect of an endpoint, groups of endpoints, or an entire network. The practice can also be used to create continuous monitoring rules on an endpoint as well as automate server tasks. Specific use cases can include:

  • Client monitoring and alerts (detection): DFIR tools can collect event queries focused on detection, allowing practitioners to autonomously monitor an endpoint and send back prioritized alerts when certain conditions are met.
  • Proactively hunting for indicators (threat intelligence): This indicates artifact collection at scale from many systems that can then be combined with threat-intelligence information – such as hashes – to proactively hunt for compromises by known bad actors. 
  • Ongoing forwarding of events to another system: Monitoring queries can be used to simply forward events.
  • Collecting bulk files for analysis on another system (digital forensics): The DFIR tool will collect bulk files from an endpoint for later analysis by other tools.
  • Parsing for indicators on the endpoint (digital forensics): Artifacts are used to directly parse files on an endpoint, quickly returning actionable, high-value information without the need for lengthy post processing.
  • Proactive hunting for indicators across many systems (incident response): The DFIR tool can simultaneously hunt for artifacts from many endpoints.

Why is DFIR a Critical Tool in a Cybersecurity Program? 

DFIR is a critical tool in a cybersecurity program because it helps to more accurately and granularly reveal the methodology and path that an attacker is looking to take or has already taken to breach a network.

It’s in the best interest of a business and its security program to go beyond response and calibrate preventive measures to recognize the same or similar behavior in the future.

What are the Benefits of DFIR? 

The benefits of DFIR are impossible to overstate, as the goal of breach investigation is visibility so that security teams can gain insights from what happened and create a stronger program.

  • Faster recovery: Surfacing more relevant alerts – based on either past incidents or library artifacts – means that DFIR practitioners can work faster to respond to and recover from an incident.  
  • Stronger security posture: In more accurately being able to respond to threats and investigate them, an organization’s overall health and security posture begins to improve. An external DFIR services program can also help to further add value by conducting more in-depth investigations, giving time back to internal practitioners to focus on other goals and priorities. 
  • Data-sharing capabilities: A modern DFIR solution will include accurate reporting of every action taken in the response to a threat or incident. This means those reports and critical insights can easily be shared with any and all interested stakeholders.  
  • Little-to-no guesswork: How did they get in? Who exactly is the perpetrator? What are their motives? Thorough DFIR capabilities should be able to provide clear answers to these questions, leaving little doubt as to what has happened and what should happen next.

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