AC – Access Control

NIST SP 800-53 Rev. 5 – AC – Access Control

1.Kravtext (engelskt original)#

AC-1 – Policy and Procedures#

• a. Develop, document, and disseminate to [organization-defined personnel or roles]:
  • 1. [organization-level or mission/business process-level or system-level] access control policy that:
    • (a) Addresses purpose, scope, roles, responsibilities, management commitment, coordination among organizational entities, and compliance; and
    • (b) Is consistent with applicable laws, executive orders, directives, regulations, policies, standards, and guidelines; and
  • 2. Procedures to facilitate the implementation of the access control policy and the associated access controls;
• b. Designate an [organization-defined official] to manage the development, documentation, and dissemination of the access control policy and procedures; and
• c. Review and update the current access control:
  • 1. Policy [organization-defined frequency] and following [organization-defined events] ; and
  • 2. Procedures [organization-defined frequency] and following [organization-defined events].

AC-2 – Account Management#

• a. Define and document the types of accounts allowed and specifically prohibited for use within the system;
• b. Assign account managers;
• c. Require [organization-defined prerequisites and criteria] for group and role membership;
• d. Specify:
  • 1. Authorized users of the system;
  • 2. Group and role membership; and
  • 3. Access authorizations (i.e., privileges) and [organization-defined attributes (as required)] for each account;
• e. Require approvals by [organization-defined personnel or roles] for requests to create accounts;
• f. Create, enable, modify, disable, and remove accounts in accordance with [organization-defined policy, procedures, prerequisites, and criteria];
• g. Monitor the use of accounts;
• h. Notify account managers and [organization-defined personnel or roles] within:
  • 1. [organization-defined time period] when accounts are no longer required;
  • 2. [organization-defined time period] when users are terminated or transferred; and
  • 3. [organization-defined time period] when system usage or need-to-know changes for an individual;
• i. Authorize access to the system based on:
  • 1. A valid access authorization;
  • 2. Intended system usage; and
  • 3. [organization-defined attributes (as required)];
• j. Review accounts for compliance with account management requirements [organization-defined frequency];
• k. Establish and implement a process for changing shared or group account authenticators (if deployed) when individuals are removed from the group; and
• l. Align account management processes with personnel termination and transfer processes.

AC-2(1) – Automated System Account Management

Support the management of system accounts using [organization-defined automated mechanisms].

AC-2(2) – Automated Temporary and Emergency Account Management

Automatically [remove or disable] temporary and emergency accounts after [organization-defined time period].

AC-2(3) – Disable Accounts

Disable accounts within [organization-defined time period] when the accounts:

• (a) Have expired;
• (b) Are no longer associated with a user or individual;
• (c) Are in violation of organizational policy; or
• (d) Have been inactive for [organization-defined time period].

AC-2(4) – Automated Audit Actions

Automatically audit account creation, modification, enabling, disabling, and removal actions.

AC-2(5) – Inactivity Logout

Require that users log out when [organization-defined time period of expected inactivity or description of when to log out].

AC-2(6) – Dynamic Privilege Management

Implement [organization-defined dynamic privilege management capabilities].

AC-2(7) – Privileged User Accounts

• (a) Establish and administer privileged user accounts in accordance with [a role-based access scheme or an attribute-based access scheme];
• (b) Monitor privileged role or attribute assignments;
• (c) Monitor changes to roles or attributes; and
• (d) Revoke access when privileged role or attribute assignments are no longer appropriate.

AC-2(8) – Dynamic Account Management

Create, activate, manage, and deactivate [organization-defined system accounts] dynamically.

AC-2(9) – Restrictions on Use of Shared and Group Accounts

Only permit the use of shared and group accounts that meet [organization-defined conditions].

AC-2(10) – Shared and Group Account Credential Change

AC-2(11) – Usage Conditions

Enforce [organization-defined circumstances and/or usage conditions] for [organization-defined system accounts].

AC-2(12) – Account Monitoring for Atypical Usage

• (a) Monitor system accounts for [organization-defined atypical usage] ; and
• (b) Report atypical usage of system accounts to [organization-defined personnel or roles].

AC-2(13) – Disable Accounts for High-risk Individuals

Disable accounts of individuals within [organization-defined time period] of discovery of [organization-defined significant risks].

AC-3 – Access Enforcement#

Enforce approved authorizations for logical access to information and system resources in accordance with applicable access control policies.

AC-3(1) – Restricted Access to Privileged Functions

AC-3(2) – Dual Authorization

Enforce dual authorization for [organization-defined privileged commands and/or other actions].

AC-3(3) – Mandatory Access Control

Enforce [organization-defined mandatory access control policy] over the set of covered subjects and objects specified in the policy, and where the policy:

• (a) Is uniformly enforced across the covered subjects and objects within the system;
• (b) Specifies that a subject that has been granted access to information is constrained from doing any of the following;
  • (1) Passing the information to unauthorized subjects or objects;
  • (2) Granting its privileges to other subjects;
  • (3) Changing one or more security attributes (specified by the policy) on subjects, objects, the system, or system components;
  • (4) Choosing the security attributes and attribute values (specified by the policy) to be associated with newly created or modified objects; and
  • (5) Changing the rules governing access control; and
• (c) Specifies that [organization-defined subjects] may explicitly be granted [organization-defined privileges] such that they are not limited by any defined subset (or all) of the above constraints.

AC-3(4) – Discretionary Access Control

Enforce [organization-defined discretionary access control policy] over the set of covered subjects and objects specified in the policy, and where the policy specifies that a subject that has been granted access to information can do one or more of the following:

• (a) Pass the information to any other subjects or objects;
• (b) Grant its privileges to other subjects;
• (c) Change security attributes on subjects, objects, the system, or the system’s components;
• (d) Choose the security attributes to be associated with newly created or revised objects; or
• (e) Change the rules governing access control.

AC-3(5) – Security-relevant Information

Prevent access to [organization-defined security-relevant information] except during secure, non-operable system states.

AC-3(6) – Protection of User and System Information

AC-3(7) – Role-based Access Control

Enforce a role-based access control policy over defined subjects and objects and control access based upon [organization-defined roles and users authorized to assume such roles].

AC-3(8) – Revocation of Access Authorizations

Enforce the revocation of access authorizations resulting from changes to the security attributes of subjects and objects based on [organization-defined rules].

AC-3(9) – Controlled Release

Release information outside of the system only if:

• (a) The receiving [organization-defined system or system component] provides [organization-defined controls] ; and
• (b) [organization-defined controls] are used to validate the appropriateness of the information designated for release.

AC-3(10) – Audited Override of Access Control Mechanisms

Employ an audited override of automated access control mechanisms under [organization-defined conditions] by [organization-defined roles].

AC-3(11) – Restrict Access to Specific Information Types

Restrict access to data repositories containing [organization-defined information types].

AC-3(12) – Assert and Enforce Application Access

• (a) Require applications to assert, as part of the installation process, the access needed to the following system applications and functions: [organization-defined system applications and functions];
• (b) Provide an enforcement mechanism to prevent unauthorized access; and
• (c) Approve access changes after initial installation of the application.

AC-3(13) – Attribute-based Access Control

Enforce attribute-based access control policy over defined subjects and objects and control access based upon [organization-defined attributes].

AC-3(14) – Individual Access

Provide [organization-defined mechanisms] to enable individuals to have access to the following elements of their personally identifiable information: [organization-defined elements].

AC-3(15) – Discretionary and Mandatory Access Control

• (a) Enforce [organization-defined mandatory access control policy] over the set of covered subjects and objects specified in the policy; and
• (b) Enforce [organization-defined discretionary access control policy] over the set of covered subjects and objects specified in the policy.

AC-4 – Information Flow Enforcement#

Enforce approved authorizations for controlling the flow of information within the system and between connected systems based on [organization-defined information flow control policies].

AC-4(1) – Object Security and Privacy Attributes

Use [organization-defined security and privacy attributes] associated with [organization-defined information, source, and destination objects] to enforce [organization-defined information flow control policies] as a basis for flow control decisions.

AC-4(2) – Processing Domains

Use protected processing domains to enforce [organization-defined information flow control policies] as a basis for flow control decisions.

AC-4(3) – Dynamic Information Flow Control

Enforce [organization-defined information flow control policies].

AC-4(4) – Flow Control of Encrypted Information

Prevent encrypted information from bypassing [organization-defined information flow control mechanisms] by [decrypting the information or blocking the flow of the encrypted information or terminating communications sessions attempting to pass encrypted information or [organization-defined procedure or method] ].

AC-4(5) – Embedded Data Types

Enforce [organization-defined limitations] on embedding data types within other data types.

AC-4(6) – Metadata

Enforce information flow control based on [organization-defined metadata].

AC-4(7) – One-way Flow Mechanisms

Enforce one-way information flows through hardware-based flow control mechanisms.

AC-4(8) – Security and Privacy Policy Filters

• (a) Enforce information flow control using [organization-defined security or privacy policy filters] as a basis for flow control decisions for [organization-defined information flows] ; and
• (b) [block or strip or modify or quarantine] data after a filter processing failure in accordance with [organization-defined security or privacy policy].

AC-4(9) – Human Reviews

Enforce the use of human reviews for [organization-defined information flows] under the following conditions: [organization-defined conditions].

AC-4(10) – Enable and Disable Security or Privacy Policy Filters

Provide the capability for privileged administrators to enable and disable [organization-defined security or privacy policy filters] under the following conditions: [organization-defined conditions].

AC-4(11) – Configuration of Security or Privacy Policy Filters

Provide the capability for privileged administrators to configure [organization-defined security or privacy policy filters] to support different security or privacy policies.

AC-4(12) – Data Type Identifiers

When transferring information between different security domains, use [organization-defined data type identifiers] to validate data essential for information flow decisions.

AC-4(13) – Decomposition into Policy-relevant Subcomponents

When transferring information between different security domains, decompose information into [organization-defined policy-relevant subcomponents] for submission to policy enforcement mechanisms.

AC-4(14) – Security or Privacy Policy Filter Constraints

When transferring information between different security domains, implement [organization-defined security or privacy policy filters] requiring fully enumerated formats that restrict data structure and content.

AC-4(15) – Detection of Unsanctioned Information

When transferring information between different security domains, examine the information for the presence of [organization-defined unsanctioned information] and prohibit the transfer of such information in accordance with the [organization-defined security or privacy policy].

AC-4(16) – Information Transfers on Interconnected Systems

AC-4(17) – Domain Authentication

Uniquely identify and authenticate source and destination points by [organization, system, application, service, individual] for information transfer.

AC-4(18) – Security Attribute Binding

AC-4(19) – Validation of Metadata

When transferring information between different security domains, implement [organization-defined security or privacy policy filters] on metadata.

AC-4(20) – Approved Solutions

Employ [organization-defined solutions in approved configurations] to control the flow of [organization-defined information] across security domains.

AC-4(21) – Physical or Logical Separation of Information Flows

Separate information flows logically or physically using [organization-defined mechanisms and/or techniques] to accomplish [organization-defined required separations].

AC-4(22) – Access Only

Provide access from a single device to computing platforms, applications, or data residing in multiple different security domains, while preventing information flow between the different security domains.

AC-4(23) – Modify Non-releasable Information

When transferring information between different security domains, modify non-releasable information by implementing [organization-defined modification action].

AC-4(24) – Internal Normalized Format

When transferring information between different security domains, parse incoming data into an internal normalized format and regenerate the data to be consistent with its intended specification.

AC-4(25) – Data Sanitization

When transferring information between different security domains, sanitize data to minimize [delivery of malicious content, command and control of malicious code, malicious code augmentation, and steganography-encoded data or spillage of sensitive information] in accordance with [organization-defined policy].

AC-4(26) – Audit Filtering Actions

When transferring information between different security domains, record and audit content filtering actions and results for the information being filtered.

AC-4(27) – Redundant/Independent Filtering Mechanisms

When transferring information between different security domains, implement content filtering solutions that provide redundant and independent filtering mechanisms for each data type.

AC-4(28) – Linear Filter Pipelines

When transferring information between different security domains, implement a linear content filter pipeline that is enforced with discretionary and mandatory access controls.

AC-4(29) – Filter Orchestration Engines

When transferring information between different security domains, employ content filter orchestration engines to ensure that:

• (a) Content filtering mechanisms successfully complete execution without errors; and
• (b) Content filtering actions occur in the correct order and comply with [organization-defined policy].

AC-4(30) – Filter Mechanisms Using Multiple Processes

When transferring information between different security domains, implement content filtering mechanisms using multiple processes.

AC-4(31) – Failed Content Transfer Prevention

When transferring information between different security domains, prevent the transfer of failed content to the receiving domain.

AC-4(32) – Process Requirements for Information Transfer

When transferring information between different security domains, the process that transfers information between filter pipelines:

• (a) Does not filter message content;
• (b) Validates filtering metadata;
• (c) Ensures the content associated with the filtering metadata has successfully completed filtering; and
• (d) Transfers the content to the destination filter pipeline.

AC-5 – Separation of Duties#

• a. Identify and document [organization-defined duties of individuals] ; and
• b. Define system access authorizations to support separation of duties.

AC-6 – Least Privilege#

Employ the principle of least privilege, allowing only authorized accesses for users (or processes acting on behalf of users) that are necessary to accomplish assigned organizational tasks.

AC-6(1) – Authorize Access to Security Functions

Authorize access for [organization-defined individuals and roles] to:

• (a) [organization-defined security functions (deployed in hardware, software, and firmware)] ; and
• (b) [organization-defined security-relevant information].

AC-6(2) – Non-privileged Access for Nonsecurity Functions

Require that users of system accounts (or roles) with access to [organization-defined security functions or security-relevant information] use non-privileged accounts or roles, when accessing nonsecurity functions.

AC-6(3) – Network Access to Privileged Commands

Authorize network access to [organization-defined privileged commands] only for [organization-defined compelling operational needs] and document the rationale for such access in the security plan for the system.

AC-6(4) – Separate Processing Domains

Provide separate processing domains to enable finer-grained allocation of user privileges.

AC-6(5) – Privileged Accounts

Restrict privileged accounts on the system to [organization-defined personnel or roles].

AC-6(6) – Privileged Access by Non-organizational Users

Prohibit privileged access to the system by non-organizational users.

AC-6(7) – Review of User Privileges

• (a) Review [organization-defined frequency] the privileges assigned to [organization-defined roles and classes] to validate the need for such privileges; and
• (b) Reassign or remove privileges, if necessary, to correctly reflect organizational mission and business needs.

AC-6(8) – Privilege Levels for Code Execution

Prevent the following software from executing at higher privilege levels than users executing the software: [organization-defined software].

AC-6(9) – Log Use of Privileged Functions

Log the execution of privileged functions.

AC-6(10) – Prohibit Non-privileged Users from Executing Privileged Functions

Prevent non-privileged users from executing privileged functions.

AC-7 – Unsuccessful Logon Attempts#

• a. Enforce a limit of [organization-defined number] consecutive invalid logon attempts by a user during a [organization-defined time period] ; and
• b. Automatically [lock the account or node for [organization-defined time period] or lock the account or node until released by an administrator or delay next logon prompt per [organization-defined delay algorithm] or notify system administrator or take other [organization-defined action] ] when the maximum number of unsuccessful attempts is exceeded.

AC-7(1) – Automatic Account Lock

AC-7(2) – Purge or Wipe Mobile Device

Purge or wipe information from [organization-defined mobile devices] based on [organization-defined purging or wiping requirements and techniques] after [organization-defined number] consecutive, unsuccessful device logon attempts.

AC-7(3) – Biometric Attempt Limiting

Limit the number of unsuccessful biometric logon attempts to [organization-defined number].

AC-7(4) – Use of Alternate Authentication Factor

• (a) Allow the use of [organization-defined authentication factors] that are different from the primary authentication factors after the number of organization-defined consecutive invalid logon attempts have been exceeded; and
• (b) Enforce a limit of [organization-defined number] consecutive invalid logon attempts through use of the alternative factors by a user during a [organization-defined time period].

AC-8 – System Use Notification#

• a. Display [organization-defined system use notification] to users before granting access to the system that provides privacy and security notices consistent with applicable laws, executive orders, directives, regulations, policies, standards, and guidelines and state that:
  • 1. Users are accessing a U.S. Government system;
  • 2. System usage may be monitored, recorded, and subject to audit;
  • 3. Unauthorized use of the system is prohibited and subject to criminal and civil penalties; and
  • 4. Use of the system indicates consent to monitoring and recording;
• b. Retain the notification message or banner on the screen until users acknowledge the usage conditions and take explicit actions to log on to or further access the system; and
• c. For publicly accessible systems:
  • 1. Display system use information [organization-defined conditions] , before granting further access to the publicly accessible system;
  • 2. Display references, if any, to monitoring, recording, or auditing that are consistent with privacy accommodations for such systems that generally prohibit those activities; and
  • 3. Include a description of the authorized uses of the system.

AC-9 – Previous Logon Notification#

Notify the user, upon successful logon to the system, of the date and time of the last logon.

AC-9(1) – Unsuccessful Logons

Notify the user, upon successful logon, of the number of unsuccessful logon attempts since the last successful logon.

AC-9(2) – Successful and Unsuccessful Logons

Notify the user, upon successful logon, of the number of [successful logons or unsuccessful logon attempts or both] during [organization-defined time period].

AC-9(3) – Notification of Account Changes

Notify the user, upon successful logon, of changes to [organization-defined security-related characteristics or parameters] during [organization-defined time period].

AC-9(4) – Additional Logon Information

Notify the user, upon successful logon, of the following additional information: [organization-defined additional information].

AC-10 – Concurrent Session Control#

Limit the number of concurrent sessions for each [organization-defined account and/or account types] to [organization-defined number].

AC-11 – Device Lock#

• a. Prevent further access to the system by [initiating a device lock after [organization-defined time period] of inactivity or requiring the user to initiate a device lock before leaving the system unattended] ; and
• b. Retain the device lock until the user reestablishes access using established identification and authentication procedures.

AC-11(1) – Pattern-hiding Displays

Conceal, via the device lock, information previously visible on the display with a publicly viewable image.

AC-12 – Session Termination#

Automatically terminate a user session after [organization-defined conditions or trigger events].

AC-12(1) – User-initiated Logouts

Provide a logout capability for user-initiated communications sessions whenever authentication is used to gain access to [organization-defined information resources].

AC-12(2) – Termination Message

Display an explicit logout message to users indicating the termination of authenticated communications sessions.

AC-12(3) – Timeout Warning Message

Display an explicit message to users indicating that the session will end in [organization-defined time].

AC-13 – Supervision and Review — Access Control#

AC-14 – Permitted Actions Without Identification or Authentication#

• a. Identify [organization-defined user actions] that can be performed on the system without identification or authentication consistent with organizational mission and business functions; and
• b. Document and provide supporting rationale in the security plan for the system, user actions not requiring identification or authentication.

AC-14(1) – Necessary Uses

AC-15 – Automated Marking#

AC-16 – Security and Privacy Attributes#

• a. Provide the means to associate [organization-defined types of security and privacy attributes] with [organization-defined security and privacy attribute values] for information in storage, in process, and/or in transmission;
• b. Ensure that the attribute associations are made and retained with the information;
• c. Establish the following permitted security and privacy attributes from the attributes defined in AC-16a for [organization-defined systems]: [organization-defined security and privacy attributes];
• d. Determine the following permitted attribute values or ranges for each of the established attributes: [organization-defined attribute values or ranges];
• e. Audit changes to attributes; and
• f. Review [organization-defined security and privacy attributes] for applicability [organization-defined frequency].

AC-16(1) – Dynamic Attribute Association

Dynamically associate security and privacy attributes with [organization-defined subjects and objects] in accordance with the following security and privacy policies as information is created and combined: [organization-defined security and privacy policies].

AC-16(2) – Attribute Value Changes by Authorized Individuals

Provide authorized individuals (or processes acting on behalf of individuals) the capability to define or change the value of associated security and privacy attributes.

AC-16(3) – Maintenance of Attribute Associations by System

Maintain the association and integrity of [organization-defined security and privacy attributes] to [organization-defined subjects and objects].

AC-16(4) – Association of Attributes by Authorized Individuals

Provide the capability to associate [organization-defined security and privacy attributes] with [organization-defined subjects and objects] by authorized individuals (or processes acting on behalf of individuals).

AC-16(5) – Attribute Displays on Objects to Be Output

Display security and privacy attributes in human-readable form on each object that the system transmits to output devices to identify [organization-defined instructions] using [organization-defined naming conventions].

AC-16(6) – Maintenance of Attribute Association

Require personnel to associate and maintain the association of [organization-defined security and privacy attributes] with [organization-defined subjects and objects] in accordance with [organization-defined security and privacy policies].

AC-16(7) – Consistent Attribute Interpretation

Provide a consistent interpretation of security and privacy attributes transmitted between distributed system components.

AC-16(8) – Association Techniques and Technologies

Implement [organization-defined techniques and technologies] in associating security and privacy attributes to information.

AC-16(9) – Attribute Reassignment — Regrading Mechanisms

Change security and privacy attributes associated with information only via regrading mechanisms validated using [organization-defined techniques or procedures].

AC-16(10) – Attribute Configuration by Authorized Individuals

Provide authorized individuals the capability to define or change the type and value of security and privacy attributes available for association with subjects and objects.

AC-17 – Remote Access#

• a. Establish and document usage restrictions, configuration/connection requirements, and implementation guidance for each type of remote access allowed; and
• b. Authorize each type of remote access to the system prior to allowing such connections.

AC-17(1) – Monitoring and Control

Employ automated mechanisms to monitor and control remote access methods.

AC-17(2) – Protection of Confidentiality and Integrity Using Encryption

Implement cryptographic mechanisms to protect the confidentiality and integrity of remote access sessions.

AC-17(3) – Managed Access Control Points

Route remote accesses through authorized and managed network access control points.

AC-17(4) – Privileged Commands and Access

• (a) Authorize the execution of privileged commands and access to security-relevant information via remote access only in a format that provides assessable evidence and for the following needs: [organization-defined needs] ; and
• (b) Document the rationale for remote access in the security plan for the system.

AC-17(5) – Monitoring for Unauthorized Connections

AC-17(6) – Protection of Mechanism Information

Protect information about remote access mechanisms from unauthorized use and disclosure.

AC-17(7) – Additional Protection for Security Function Access

AC-17(8) – Disable Nonsecure Network Protocols

AC-17(9) – Disconnect or Disable Access

Provide the capability to disconnect or disable remote access to the system within [organization-defined time period].

AC-17(10) – Authenticate Remote Commands

Implement [organization-defined mechanisms] to authenticate [organization-defined remote commands].

AC-18 – Wireless Access#

• a. Establish configuration requirements, connection requirements, and implementation guidance for each type of wireless access; and
• b. Authorize each type of wireless access to the system prior to allowing such connections.

AC-18(1) – Authentication and Encryption

Protect wireless access to the system using authentication of [users or devices] and encryption.

AC-18(2) – Monitoring Unauthorized Connections

AC-18(3) – Disable Wireless Networking

Disable, when not intended for use, wireless networking capabilities embedded within system components prior to issuance and deployment.

AC-18(4) – Restrict Configurations by Users

Identify and explicitly authorize users allowed to independently configure wireless networking capabilities.

AC-18(5) – Antennas and Transmission Power Levels

Select radio antennas and calibrate transmission power levels to reduce the probability that signals from wireless access points can be received outside of organization-controlled boundaries.

AC-19 – Access Control for Mobile Devices#

• a. Establish configuration requirements, connection requirements, and implementation guidance for organization-controlled mobile devices, to include when such devices are outside of controlled areas; and
• b. Authorize the connection of mobile devices to organizational systems.

AC-19(1) – Use of Writable and Portable Storage Devices

AC-19(2) – Use of Personally Owned Portable Storage Devices

AC-19(3) – Use of Portable Storage Devices with No Identifiable Owner

AC-19(4) – Restrictions for Classified Information

• (a) Prohibit the use of unclassified mobile devices in facilities containing systems processing, storing, or transmitting classified information unless specifically permitted by the authorizing official; and
• (b) Enforce the following restrictions on individuals permitted by the authorizing official to use unclassified mobile devices in facilities containing systems processing, storing, or transmitting classified information:
  • (1) Connection of unclassified mobile devices to classified systems is prohibited;
  • (2) Connection of unclassified mobile devices to unclassified systems requires approval from the authorizing official;
  • (3) Use of internal or external modems or wireless interfaces within the unclassified mobile devices is prohibited; and
  • (4) Unclassified mobile devices and the information stored on those devices are subject to random reviews and inspections by [organization-defined security officials] , and if classified information is found, the incident handling policy is followed.
• (c) Restrict the connection of classified mobile devices to classified systems in accordance with [organization-defined security policies].

AC-19(5) – Full Device or Container-based Encryption

Employ [full-device encryption or container-based encryption] to protect the confidentiality and integrity of information on [organization-defined mobile devices].

AC-20 – Use of External Systems#

• a. [establish [organization-defined terms and conditions] or identify [organization-defined controls asserted] ] , consistent with the trust relationships established with other organizations owning, operating, and/or maintaining external systems, allowing authorized individuals to:
  • 1. Access the system from external systems; and
  • 2. Process, store, or transmit organization-controlled information using external systems; or
• b. Prohibit the use of [organization-defined prohibited types of external systems].

AC-20(1) – Limits on Authorized Use

Permit authorized individuals to use an external system to access the system or to process, store, or transmit organization-controlled information only after:

• (a) Verification of the implementation of controls on the external system as specified in the organization’s security and privacy policies and security and privacy plans; or
• (b) Retention of approved system connection or processing agreements with the organizational entity hosting the external system.

AC-20(2) – Portable Storage Devices — Restricted Use

Restrict the use of organization-controlled portable storage devices by authorized individuals on external systems using [organization-defined restrictions].

AC-20(3) – Non-organizationally Owned Systems — Restricted Use

Restrict the use of non-organizationally owned systems or system components to process, store, or transmit organizational information using [organization-defined restrictions].

AC-20(4) – Network Accessible Storage Devices — Prohibited Use

Prohibit the use of [organization-defined network-accessible storage devices] in external systems.

AC-20(5) – Portable Storage Devices — Prohibited Use

Prohibit the use of organization-controlled portable storage devices by authorized individuals on external systems.

AC-21 – Information Sharing#

• a. Enable authorized users to determine whether access authorizations assigned to a sharing partner match the information’s access and use restrictions for [organization-defined information-sharing circumstances] ; and
• b. Employ [organization-defined automated mechanisms] to assist users in making information sharing and collaboration decisions.

AC-21(1) – Automated Decision Support

Employ [organization-defined automated mechanisms] to enforce information-sharing decisions by authorized users based on access authorizations of sharing partners and access restrictions on information to be shared.

AC-21(2) – Information Search and Retrieval

Implement information search and retrieval services that enforce [organization-defined information-sharing restrictions].

AC-22 – Publicly Accessible Content#

• a. Designate individuals authorized to make information publicly accessible;
• b. Train authorized individuals to ensure that publicly accessible information does not contain nonpublic information;
• c. Review the proposed content of information prior to posting onto the publicly accessible system to ensure that nonpublic information is not included; and
• d. Review the content on the publicly accessible system for nonpublic information [organization-defined frequency] and remove such information, if discovered.

AC-23 – Data Mining Protection#

Employ [organization-defined techniques] for [organization-defined data storage objects] to detect and protect against unauthorized data mining.

AC-24 – Access Control Decisions#

[establish procedures or implement mechanisms] to ensure [organization-defined access control decisions] are applied to each access request prior to access enforcement.

AC-24(1) – Transmit Access Authorization Information

Transmit [organization-defined access authorization information] using [organization-defined controls] to [organization-defined systems] that enforce access control decisions.

AC-24(2) – No User or Process Identity

Enforce access control decisions based on [organization-defined security or privacy attributes] that do not include the identity of the user or process acting on behalf of the user.

AC-25 – Reference Monitor#

Implement a reference monitor for [organization-defined access control policies] that is tamperproof, always invoked, and small enough to be subject to analysis and testing, the completeness of which can be assured.

National Institute of Standards and Technology, OSCAL release 5.2.0. Republished courtesy of the National Institute of Standards and Technology. CC0 1.0. Source.