Evidence collection and chain of custody are forensic disciplines that ensure digital evidence is gathered, preserved, and documented in a manner that maintains its integrity and admissibility in legal proceedings. Chain of custody is the chronological documentation of evidence handling from the moment of collection through analysis, storage, and presentation. Proper evidence handling is critical when incidents may result in criminal prosecution, civil litigation, regulatory action, or insurance claims.
Evidence collection follows a strict order of volatility, capturing the most ephemeral data first: CPU registers and cache, memory contents, network connections, running processes, disk contents, and finally removable media and backups. Each evidence item is collected using forensically sound tools that create verified copies without modifying the original. Write blockers prevent inadvertent changes to storage media. Cryptographic hashes (SHA-256) are calculated at collection time and verified at each subsequent handling event. Chain of custody documentation records who collected the evidence, when, where, how, and every subsequent transfer of possession. Evidence is stored in tamper-evident containers in secure, access-controlled environments with environmental monitoring.
Digital evidence is inherently fragile -- a single unlogged access or improper handling procedure can render critical evidence inadmissible in court. Without proper chain of custody, an organization may be unable to prosecute attackers, pursue civil remedies, or demonstrate regulatory compliance. Insurance carriers increasingly require forensic evidence to process cyber insurance claims. Even when legal proceedings are not anticipated, proper evidence collection preserves options and protects the organization's interests.
CDA's TID domain missions include evidence handling procedures aligned with NIST SP 800-86 and law enforcement standards. Our C-HARDEN campaigns train incident responders in forensically sound collection techniques, and CDA's Locker provides secure evidence storage with full audit trails. Every CDA operator understands that evidence integrity is non-negotiable and that proper chain of custody begins at the moment of detection.