Certified: The CISSP Prepcast

Welcome to The Bare Metal Cyber CISSP Prepcast. This series helps you prepare for the ISC squared CISSP exam with focused explanations and practical context.
In this episode, we will focus on Digital Forensics and Chain of Custody—two tightly linked practices that are essential to incident investigation, evidence preservation, and legal or regulatory compliance. When a cybersecurity incident occurs, identifying the cause and assessing the impact is only part of the response. Often, there is a legal dimension that requires proof, documentation, and a carefully structured process to maintain evidence integrity. That’s where digital forensics and proper chain-of-custody procedures come into play.
Digital forensics and chain of custody form the bridge between technical response and legal accountability. Without them, your incident response may be incomplete, inadmissible in court, or viewed as unreliable by auditors, regulators, or business partners. If you are preparing for the Certified Information Systems Security Professional exam, it is crucial to understand how these practices function together to support effective and defensible cybersecurity incident handling.
Let’s begin with the basics of digital forensics. Digital forensics is the process of collecting, analyzing, and preserving electronic data in a manner that maintains its integrity and supports investigative and legal requirements. In the context of cybersecurity, digital forensics helps organizations understand how an incident occurred, what systems or data were affected, and what malicious activities took place.
Digital forensics is not just about recovery—it’s about evidence. It provides technical support for legal cases, regulatory inquiries, insurance claims, and internal disciplinary actions. A strong forensic program allows organizations to investigate insider threats, reconstruct cyberattacks, and prepare detailed, defensible incident reports.
A proper forensic process helps preserve the timeline of an incident, identify root causes, and detect security gaps. For example, forensic analysis might show that a threat actor exploited a misconfigured firewall, used stolen credentials to access a server, and exfiltrated data over a series of outbound connections. These findings are valuable not only for responding to the immediate threat but also for improving security posture going forward.
Understanding the fundamentals of digital forensics enables cybersecurity teams to maintain accountability, ensure accurate reporting, and demonstrate due diligence. Forensics turns chaos into clarity, turning fragmented data into a structured narrative that explains what happened, when it happened, and how to prevent it in the future.
Now let’s shift to the importance of chain of custody. Chain of custody refers to the documentation of the entire lifecycle of evidence—from the moment it is collected to the moment it is presented in court or archived. It tracks who handled the evidence, when they handled it, where it was stored, and what actions were taken at each stage.
In legal or regulatory contexts, the chain of custody is often the most scrutinized aspect of an investigation. If the chain is broken—if there is a period where no one can account for the evidence’s location or status—the evidence may be considered compromised and could be ruled inadmissible.
Managing the chain of custody is about ensuring trust. It shows that the evidence was not tampered with, altered, or lost. It adds credibility to your forensic findings and supports the legitimacy of your incident response. Whether you are dealing with law enforcement, internal auditors, or external regulators, the ability to prove that your evidence is trustworthy is critical.
A proper chain-of-custody process includes timestamps, names of handlers, descriptions of the evidence, the actions performed on it, and the physical or digital storage locations used throughout the process. It ensures transparency and accountability and reinforces the strength of your organization’s security operations.
Now let’s talk about effective digital forensic practices. First, every organization that performs digital forensics should define its procedures and methodologies in advance. This includes specifying what tools will be used, how evidence will be collected, how systems will be imaged, and how documentation will be handled. These procedures should follow accepted standards, such as those outlined by the National Institute of Standards and Technology or other recognized forensic frameworks.
The evidence collection process must be systematic. It should begin with forensic imaging—a process where exact bit-by-bit copies of drives, memory, or network traffic are created. Imaging ensures that the original data remains unchanged and can be analyzed without risk of corruption.
Data hashing is also essential. Hashing involves applying an algorithm to a piece of data to produce a unique value. This value can later be used to verify that the data has not been altered. If the hash value of a forensic image changes, it indicates that the data has been modified—and may no longer be trustworthy.
Timestamping, log correlation, and artifact examination all play key roles in forensic analysis. Analysts reconstruct timelines, examine file metadata, investigate registry changes, and analyze system logs to determine how the incident unfolded. Every step must be documented clearly, including how the analysis was performed and what conclusions were drawn.
Forensic teams must validate their tools and processes. Tools should be tested regularly to ensure accuracy. Analysts must undergo training and certification to remain competent and current. Forensics is both an art and a science—it requires precision, judgment, and constant learning.
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Now let’s look more closely at how to maintain a proper chain of custody. Begin by establishing secure and standardized procedures for how evidence will be documented. Every piece of evidence should be logged immediately at the point of collection. This includes assigning a unique identifier, describing the item, recording who collected it, and specifying where it will be stored.
Use standardized custody forms to track each time evidence is accessed, transferred, analyzed, or moved to a new storage location. Each action should include a timestamp, the name of the person involved, the reason for the action, and any changes made to the evidence state.
Storage must be secure. Digital evidence should be stored in access-controlled systems, ideally with audit logs showing who accessed what and when. Encryption should be applied to sensitive data, and physical storage areas should have locks, alarms, and surveillance controls.
Chain of custody procedures should also be audited. This means reviewing custody records periodically to confirm accuracy and adherence to policy. If any irregularities are found—such as a missing timestamp or an unexplained transfer—they must be investigated and corrected.
Training is key. Everyone involved in handling forensic evidence should receive training in chain-of-custody management. This includes not only forensic analysts, but also incident responders, legal advisors, and anyone who may serve as a custodian or reviewer of evidence.
Let’s now turn to the security controls that support forensic processes and chain of custody. Start with secure forensic tools and tamper-proof storage systems. Imaging software should support hashing and logging. Storage systems should enforce access controls, support encryption, and generate audit trails.
Authentication must be strict. Only authorized personnel should be able to access forensic data or chain-of-custody records. Logging and monitoring systems should be in place to detect unauthorized access attempts or anomalous behavior.
Regular audits, vulnerability assessments, and penetration tests help confirm that forensic infrastructure is secure and functioning properly. This includes both hardware and software components used in evidence collection, analysis, and reporting.
Backups are essential. Evidence must be preserved for potential legal action, which could occur months or even years after an incident. Secure backups, offsite storage, and archival systems ensure that data is preserved and available when needed.
During collection and reporting, secure communication channels must be used. Whether you are transferring evidence between offices or emailing a forensic report, encryption and secure protocols should always be applied to prevent interception or tampering.
Finally, let’s talk about continuous improvement in digital forensics. Forensic techniques and chain-of-custody practices must evolve alongside threats, technologies, and legal requirements. Your procedures should be reviewed regularly to reflect new tools, updated legal standards, and lessons learned from recent incidents.
Use feedback from forensic reviews to improve training, processes, and controls. Cross-functional collaboration enhances the process. Work with legal, compliance, IT, and operations to ensure that forensic activities are consistent, thorough, and legally sound.
Ongoing training helps maintain competency. Offer refresher courses, simulation exercises, and certification opportunities for your forensic team. Encourage knowledge sharing across departments and stay current with industry developments.
Thank you for joining the CISSP Prepcast by Bare Metal Cyber. Visit baremetalcyber.com for additional episodes, comprehensive CISSP study resources, and personalized certification support. Deepen your understanding of Digital Forensics and Chain of Custody, and we'll consistently support your journey toward CISSP certification success.