NIST SP 800-61

Even though information security professionals plan to effectively manage risk, incidents still occur. NIST SP 800-61 is the National Institute of Standards and Technology (NIST) special publication that gives guidelines for organizations on how to handle security incidents. Read section 2.2 on page 6 to learn more about the need for, and the benefits of, an incident response capability. Also read section 3 on pages 21-44 to learn how to appropriately handle information security incidents. Before you move on, make sure you can explain the four stages of the incident response process: preparation; detection and analysis; containment, eradication, and recovery; and post-incident activity.

Handling an Incident

3.2. Evidence Gathering and Handling

Although the primary reason for gathering evidence during an incident is to resolve the incident, it may also be needed for legal proceedings. In such cases, it is important to clearly document how all evidence, including compromised systems, has been preserved. Evidence should be collected according to procedures that meet all applicable laws and regulations that have been developed from previous discussions with legal staff and appropriate law enforcement agencies so that any evidence can be admissible in court. In addition, evidence should be accounted for at all times; whenever evidence is transferred from person to person, chain of custody forms should detail the transfer and include each party's signature. A detailed log should be kept for all evidence, including the following:

  • Identifying information (e.g., the location, serial number, model number, hostname, media access control (MAC) addresses, and IP addresses of a computer) 
  • Name, title, and phone number of each individual who collected or handled the evidence during the investigation
  • Time and date (including time zone) of each occurrence of evidence handling 
  • Locations where the evidence was stored.

Collecting evidence from computing resources presents some challenges. It is generally desirable to acquire evidence from a system of interest as soon as one suspects that an incident may have occurred. Many incidents cause a dynamic chain of events to occur; an initial system snapshot may do more good in identifying the problem and its source than most other actions that can be taken at this stage. From an evidentiary standpoint, it is much better to get a snapshot of the system as-is rather than doing so after incident handlers, system administrators, and others have inadvertently altered the state of the machine during the investigation. Users and system administrators should be made aware of the steps that they should take to preserve evidence. See NIST SP 800-86, Guide to Integrating Forensic Techniques into Incident Response, for additional information on preserving evidence.