NIST SP 800-53 Rev. 5 Common Control Library

NIST control statement

a. Identify the types of events that the system is capable of logging in support of the audit function: [Assignment: event types]; b. Coordinate the event logging function with other organizational entities requiring audit-related information to guide and inform the selection criteria for events to be logged; c. Specify the following event types for logging within the system: [Assignment: organization-defined event types (subset of the event types defined in [AU-2a.](#au-2_smt.a)) along with the frequency of (or situation requiring) logging for each identified event type]; d. Provide a rationale for why the event types selected for logging are deemed to be adequate to support after-the-fact investigations of incidents; and e. Review and update the event types selected for logging [Assignment: frequency].

Discussion

An event is an observable occurrence in a system. The types of events that require logging are those events that are significant and relevant to the security of systems and the privacy of individuals. Event logging also supports specific monitoring and auditing needs. Event types include password changes, failed logons or failed accesses related to systems, security or privacy attribute changes, administrative privilege usage, PIV credential usage, data action changes, query parameters, or external credential usage. In determining the set of event types that require logging, organizations consider the monitoring and auditing appropriate for each of the controls to be implemented. For completeness, event logging includes all protocols that are operational and supported by the system. To balance monitoring and auditing requirements with other system needs, event logging requires identifying the subset of event types that are logged at a given point in time. For example, organizations may determine that systems need the capability to log every file access successful and unsuccessful, but not activate that capability except for specific circumstances due to the potential burden on system performance. The types of events that organizations desire to be logged may change. Reviewing and updating the set of logged events is necessary to help ensure that the events remain relevant and continue to support the needs of the organization. Organizations consider how the types of logging events can reveal information about individuals that may give rise to privacy risk and how best to mitigate such risks. For example, there is the potential to reveal personally identifiable information in the audit trail, especially if the logging event is based on patterns or time of usage. Event logging requirements, including the need to log specific event types, may be referenced in other controls and control enhancements. These include [AC-2(4)](#ac-2.4), [AC-3(10)](#ac-3.10), [AC-6(9)](#ac-6.9), [AC-17(1)](#ac-17.1), [CM-3f](#cm-3_smt.f), [CM-5(1)](#cm-5.1), [IA-3(3)(b)](#ia-3.3_smt.b), [MA-4(1)](#ma-4.1), [MP-4(2)](#mp-4.2), [PE-3](#pe-3), [PM-21](#pm-21), [PT-7](#pt-7), [RA-8](#ra-8), [SC-7(9)](#sc-7.9), [SC-7(15)](#sc-7.15), [SI-3(8)](#si-3.8), [SI-4(22)](#si-4.22), [SI-7(8)](#si-7.8) , and [SI-10(1)](#si-10.1) . Organizations include event types that are required by applicable laws, executive orders, directives, policies, regulations, standards, and guidelines. Audit records can be generated at various levels, including at the packet level as information traverses the network. Selecting the appropriate level of event logging is an important part of a monitoring and auditing capability and can identify the root causes of problems. When defining event types, organizations consider the logging necessary to cover related event types, such as the steps in distributed, transaction-based processes and the actions that occur in service-oriented architectures.

NIST control statement

Uniquely identify and authenticate [Assignment: devices and/or types of devices] before establishing a [Selection (one-or-more): local; remote; network] connection.

Discussion

Devices that require unique device-to-device identification and authentication are defined by type, device, or a combination of type and device. Organization-defined device types include devices that are not owned by the organization. Systems use shared known information (e.g., Media Access Control [MAC], Transmission Control Protocol/Internet Protocol [TCP/IP] addresses) for device identification or organizational authentication solutions (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.1x and Extensible Authentication Protocol [EAP], RADIUS server with EAP-Transport Layer Security [TLS] authentication, Kerberos) to identify and authenticate devices on local and wide area networks. Organizations determine the required strength of authentication mechanisms based on the security categories of systems and mission or business requirements. Because of the challenges of implementing device authentication on a large scale, organizations can restrict the application of the control to a limited number/type of devices based on mission or business needs.

NIST control statement

Authenticate [Assignment: devices and/or types of devices] before establishing [Selection (one-or-more): local; remote; network] connection using bidirectional authentication that is cryptographically based.

Discussion

A local connection is a connection with a device that communicates without the use of a network. A network connection is a connection with a device that communicates through a network. A remote connection is a connection with a device that communicates through an external network. Bidirectional authentication provides stronger protection to validate the identity of other devices for connections that are of greater risk.

NIST control statement

Withdrawn in this source release; review the official source for disposition.

NIST control statement

(a) Where addresses are allocated dynamically, standardize dynamic address allocation lease information and the lease duration assigned to devices in accordance with [Assignment: organization-defined lease information and lease duration] ; and (b) Audit lease information when assigned to a device.

Discussion

The Dynamic Host Configuration Protocol (DHCP) is an example of a means by which clients can dynamically receive network address assignments.

NIST control statement

Handle device identification and authentication based on attestation by [Assignment: configuration management process].

Discussion

Device attestation refers to the identification and authentication of a device based on its configuration and known operating state. Device attestation can be determined via a cryptographic hash of the device. If device attestation is the means of identification and authentication, then it is important that patches and updates to the device are handled via a configuration management process such that the patches and updates are done securely and do not disrupt identification and authentication to other devices.

NIST control statement

Maintain the attributes for each uniquely identified individual, device, or service in [Assignment: protected central storage].

Discussion

For each of the entities covered in [IA-2](#ia-2), [IA-3](#ia-3), [IA-8](#ia-8) , and [IA-9](#ia-9) , it is important to maintain the attributes for each authenticated entity on an ongoing basis in a central (protected) store.