Overview

Security Requirements for 03.03.03 Event Review

The intent of this requirement is to periodically re-evaluate which logged events will continue to be included in the list of events to be logged. The event types that are logged by organizations may change over time. Reviewing and updating the set of logged event types periodically is necessary to ensure that the current set remains necessary and sufficient.

Assessment GuidanceExamine 0/8

How an assessor determines this requirement is met. Source: CMMC Assessment Guide – Level 2, Version 2.13 (NIST SP 800-171 Rev. 2).

Discussion

This requirement is focused on the configuration of the auditing system, not the review of the audit records produced by the selected events. The review of the audit logs is covered under AU.L2-3.3.5 and AU.L2-3.3.6.

Example You are in charge of IT operations for a company that processes CUI and are responsible for identifying and documenting which events are relevant to the security of your company’s systems. Your company has decided that this list of events should be updated annually or when new security threats or events have been identified, which may require additional events to be logged and reviewed [a]. The list of events you are capturing in your logs started as the list of recommended events given by the manufacturers of your operating systems and devices, but it has grown from experience. Your company experiences a security incident, and a forensics review shows the logs appear to have been deleted by a remote user. You notice that remote sessions are not currently being logged [b]. You update the list of events to include logging all VPN sessions [c].

Assessment Methods

Examine
The process of reviewing, inspecting, observing, studying, or analyzing assessment objects (e.g., policies, procedures, plans, system designs, mechanisms) to facilitate understanding, achieve clarification, or obtain evidence.Example: An assessor reads the access control policy and inspects system configuration settings to confirm they match.

Not all of the evidence listed is required to meet this requirement — check the items your organization has collected.

Interview
The process of holding discussions with individuals or groups within an organization to facilitate understanding, achieve clarification, or identify the location of evidence.Example: An assessor asks a system administrator to describe how user accounts are approved, reviewed, and disabled.
  • Personnel with audit and accountability responsibilities
  • Personnel with information security responsibilities
Test
The process of exercising assessment objects (e.g., activities, mechanisms) under specified conditions to compare actual behavior with expected behavior.Example: An assessor attempts to sign in with a disabled account to confirm that access is denied.
  • Mechanisms supporting review and update of logged event types

Potential Assessment Considerations

  • Do documented processes include methods for determining when to review logged event types (i.e., regular frequency, after incidents, after major system changes) [a]?
  • Do documented processes include methods for reviewing event types being logged (i.e., based on specific threat, use case, retention capacity, current utilization, and/or newly added system component or functionality) [b]?

Key References

NIST SP 800-171 Rev. 2 3.3.3

Evidence

  1. 03.03.03.a

    A process for determining when to review logged events is defined

  1. 03.03.03.b

    Event types being logged are reviewed in accordance with the defined review process

  1. 03.03.03.c

    Event types being logged are updated based on the review