Define the term "chain of custody" in the context of incident response.

In the context of incident response, the term "chain of custody" refers to the meticulous documentation and control of evidence gathered during the investigation of a security incident or a cybercrime. The purpose of maintaining a chain of custody is to ensure the integrity and admissibility of the evidence in legal proceedings, should they arise. The concept is borrowed from forensic science and is critical in both digital and physical investigations.

  1. Identification and Collection:
    • When an incident is detected, the incident response team identifies and collects relevant digital and physical evidence. This could include log files, system snapshots, memory dumps, network traffic captures, and any other artifacts associated with the incident.
  2. Documentation:
    • Each piece of evidence is documented thoroughly. This documentation includes details such as the date and time of collection, the location of the evidence, the personnel involved, and any relevant environmental conditions. Digital evidence, in particular, may require specific metadata, such as file hashes or digital signatures, to ensure its integrity.
  3. Packaging and Labeling:
    • Evidence is carefully packaged to prevent contamination or damage. Digital evidence might be stored on write-protected media or using specialized tools to ensure that it remains unchanged. Physical evidence might be sealed in tamper-evident bags or containers. Each package is labeled with a unique identifier that correlates with the documentation.
  4. Transportation:
    • If the investigation involves multiple locations, the evidence is transported securely. This may involve using encrypted channels for digital evidence or physical security measures for transporting physical evidence. The goal is to prevent any tampering, loss, or compromise during transit.
  5. Storage:
    • Evidence is stored in a secure environment, often in a controlled access facility. Digital evidence might be stored on servers with restricted access, while physical evidence may be stored in a locked evidence room. Access to the evidence should be limited to authorized personnel.
  6. Access and Handling:
    • Access to the evidence is restricted to authorized individuals, and any handling of the evidence is documented. This includes logging each time the evidence is accessed, by whom, and for what purpose. Any changes made during the investigation should be documented to maintain the integrity of the chain of custody.
  7. Legal Considerations:
    • Throughout the process, legal considerations are paramount. Adhering to the chain of custody protocols ensures that the evidence is admissible in court. This involves following established procedures, maintaining accurate documentation, and preserving the original state of the evidence.
  8. Chain of Custody Logs:
    • A detailed log is maintained, often referred to as the "chain of custody log." This log tracks every step of the evidence handling process, providing a comprehensive record that can be used to verify the integrity and authenticity of the evidence.