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AC-18: WIRELESS ACCESS

TAILORED FOR INDUSTRIAL CONTROL SYSTEMS

  • ICS Control Baselines:
  • Low
  • Moderate
  • High

The organization:

    • a. Establishes usage restrictions, configuration/connection requirements, and implementation guidance for wireless access; and
    • b. Authorizes wireless access to the information system prior to allowing such connections.

SUPPLEMENTAL GUIDANCE

Wireless technologies include, for example, microwave, packet radio (UHF/VHF), 802.11x, and Bluetooth. Wireless networks use authentication protocols (e.g., EAP/TLS, PEAP), which provide credential protection and mutual authentication.

ICS SUPPLEMENTAL GUIDANCE

In situations where the ICS cannot implement any or all of the components of this control, the organization employs other mechanisms or procedures as compensating controls in accordance with the general tailoring guidance.

CONTROL ENHANCEMENTS

AC-18 (1) WIRELESS ACCESS | AUTHENTICATION AND ENCRYPTION
  • ICS Control Baselines:
  • Moderate
  • High

The information system protects wireless access to the system using authentication of [Selection (one or more): users; devices] and encryption.

Supplemental Guidance: NONE

ICS Supplemental Guidance:

See AC-17. Example compensating controls include providing increased auditing for wireless access or limiting wireless access privileges to key personnel.

RELATED CONTROLS: AC-18 (1)

AC-18 (2) WIRELESS ACCESS | MONITORING UNAUTHORIZED CONNECTIONS

[Withdrawn: Incorporated into SI-4].

AC-18 (3) WIRELESS ACCESS | DISABLE WIRELESS NETWORKING

NOT SELECTED FOR THE NIST ISC CONTROL SET

The organization disables, when not intended for use, wireless networking capabilities internally embedded within information system components prior to issuance and deployment.

Supplemental Guidance: NONE

RELATED CONTROLS: AC-18 (3)

AC-18 (4) WIRELESS ACCESS | RESTRICT CONFIGURATIONS BY USERS
  • ISC Control Baseline:
  • High

The organization identifies and explicitly authorizes users allowed to independently configure wireless networking capabilities.

Supplemental Guidance:

Organizational authorizations to allow selected users to configure wireless networking capability are enforced in part, by the access enforcement mechanisms employed within organizational information systems.

No ICS Supplemental Guidance.

RELATED CONTROLS: AC-18 (4)

AC-18 (5) WIRELESS ACCESS | ANTENNAS/TRANSMISSION POWER LEVELS
  • ISC Control Baseline:
  • High

The organization selects radio antennas and calibrates transmission power levels to reduce the probability that usable signals can be received outside of organization-controlled boundaries.

Supplemental Guidance:

Actions that may be taken by organizations to limit unauthorized use of wireless communications outside of organization-controlled boundaries include, for example: (i) reducing the power of wireless transmissions so that the transmissions are less likely to emit a signal that can be used by adversaries outside of the physical perimeters of organizations; (ii) employing measures such as TEMPEST to control wireless emanations; and (iii) using directional/beam forming antennas that reduce the likelihood that unintended receivers will be able to intercept signals. Prior to taking such actions, organizations can conduct periodic wireless surveys to understand the radio frequency profile of organizational information systems as well as other systems that may be operating in the area.

No ICS Supplemental Guidance.

RELATED CONTROLS: AC-18 (5)

REFERENCES:

  • NIST Special Publication 800-82 | GUIDE TO INDUSTRIAL CONTROL SYSTEMS (ICS) SECURITY
  • NIST Special Publication 800-48
  • NIST Special Publication 800-94
  • NIST Special Publication 800-97