nistonomicon

{ "controls:controls": { "$": { "xmlns": "http://scap.nist.gov/schema/sp800-53/2.0", "xmlns:controls": "http://scap.nist.gov/schema/sp800-53/feed/2.0", "xmlns:xhtml": "http://www.w3.org/1999/xhtml", "xmlns:xsi": "http://www.w3.org/2001/XMLSchema-instance", "pub_date": "2015-02-03T10:11:18.645-05:00", "xsi:schemaLocation": "http://scap.nist.gov/schema/sp800-53/feed/2.0 http://scap.nist.gov/schema/sp800-53/feed/2.0/sp800-53-feed_2.0.xsd" }, "controls:control": [ { "family": "ACCESS CONTROL", "number": "AC-1", "title": "ACCESS CONTROL POLICY AND PROCEDURES", "priority": "P1", "baseline-impact": [ "LOW", "MODERATE", "HIGH" ], "statement": { "description": "The organization:", "statement": [ { "number": "AC-1a.", "description": "Develops, documents, and disseminates to [Assignment: organization-defined personnel or roles]:", "statement": [ { "number": "AC-1a.1.", "description": "An access control policy that addresses purpose, scope, roles, responsibilities, management commitment, coordination among organizational entities, and compliance; and" }, { "number": "AC-1a.2.", "description": "Procedures to facilitate the implementation of the access control policy and associated access controls; and" } ] }, { "number": "AC-1b.", "description": "Reviews and updates the current:", "statement": [ { "number": "AC-1b.1.", "description": "Access control policy [Assignment: organization-defined frequency]; and" }, { "number": "AC-1b.2.", "description": "Access control procedures [Assignment: organization-defined frequency]." } ] } ] }, "supplemental-guidance": { "description": "This control addresses the establishment of policy and procedures for the effective implementation of selected security controls and control enhancements in the AC family. Policy and procedures reflect applicable federal laws, Executive Orders, directives, regulations, policies, standards, and guidance. Security program policies and procedures at the organization level may make the need for system-specific policies and procedures unnecessary. The policy can be included as part of the general information security policy for organizations or conversely, can be represented by multiple policies reflecting the complex nature of certain organizations. The procedures can be established for the security program in general and for particular information systems, if needed. The organizational risk management strategy is a key factor in establishing policy and procedures.", "related": "PM-9" }, "references": { "reference": [ { "item": { "_": "NIST Special Publication 800-12", "$": { "xml:lang": "en-US", "href": "http://csrc.nist.gov/publications/PubsSPs.html#800-12" } } }, { "item": { "_": "NIST Special Publication 800-100", "$": { "xml:lang": "en-US", "href": "http://csrc.nist.gov/publications/PubsSPs.html#800-100" } } } ] } }, { "family": "ACCESS CONTROL", "number": "AC-2", "title": "ACCOUNT MANAGEMENT", "priority": "P1", "baseline-impact": [ "LOW", "MODERATE", "HIGH" ], "statement": { "description": "The organization:", "statement": [ { "number": "AC-2a.", "description": "Identifies and selects the following types of information system accounts to support organizational missions/business functions: [Assignment: organization-defined information system account types];" }, { "number": "AC-2b.", "description": "Assigns account managers for information system accounts;" }, { "number": "AC-2c.", "description": "Establishes conditions for group and role membership;" }, { "number": "AC-2d.", "description": "Specifies authorized users of the information system, group and role membership, and access authorizations (i.e., privileges) and other attributes (as required) for each account;" }, { "number": "AC-2e.", "description": "Requires approvals by [Assignment: organization-defined personnel or roles] for requests to create information system accounts;" }, { "number": "AC-2f.", "description": "Creates, enables, modifies, disables, and removes information system accounts in accordance with [Assignment: organization-defined procedures or conditions];" }, { "number": "AC-2g.", "description": "Monitors the use of information system accounts;" }, { "number": "AC-2h.", "description": "Notifies account managers:", "statement": [ { "number": "AC-2h.1.", "description": "When accounts are no longer required;" }, { "number": "AC-2h.2.", "description": "When users are terminated or transferred; and" }, { "number": "AC-2h.3.", "description": "When individual information system usage or need-to-know changes;" } ] }, { "number": "AC-2i.", "description": "Authorizes access to the information system based on:", "statement": [ { "number": "AC-2i.1.", "description": "A valid access authorization;" }, { "number": "AC-2i.2.", "description": "Intended system usage; and" }, { "number": "AC-2i.3.", "description": "Other attributes as required by the organization or associated missions/business functions;" } ] }, { "number": "AC-2j.", "description": "Reviews accounts for compliance with account management requirements [Assignment: organization-defined frequency]; and" }, { "number": "AC-2k.", "description": "Establishes a process for reissuing shared/group account credentials (if deployed) when individuals are removed from the group." } ] }, "supplemental-guidance": { "description": "Information system account types include, for example, individual, shared, group, system, guest/anonymous, emergency, developer/manufacturer/vendor, temporary, and service. Some of the account management requirements listed above can be implemented by organizational information systems. The identification of authorized users of the information system and the specification of access privileges reflects the requirements in other security controls in the security plan. Users requiring administrative privileges on information system accounts receive additional scrutiny by appropriate organizational personnel (e.g., system owner, mission/business owner, or chief information security officer) responsible for approving such accounts and privileged access. Organizations may choose to define access privileges or other attributes by account, by type of account, or a combination of both. Other attributes required for authorizing access include, for example, restrictions on time-of-day, day-of-week, and point-of-origin. In defining other account attributes, organizations consider system-related requirements (e.g., scheduled maintenance, system upgrades) and mission/business requirements, (e.g., time zone differences, customer requirements, remote access to support travel requirements). Failure to consider these factors could affect information system availability. Temporary and emergency accounts are accounts intended for short-term use. Organizations establish temporary accounts as a part of normal account activation procedures when there is a need for short-term accounts without the demand for immediacy in account activation. Organizations establish emergency accounts in response to crisis situations and with the need for rapid account activation. Therefore, emergency account activation may bypass normal account authorization processes. Emergency and temporary accounts are not to be confused with infrequently used accounts (e.g., local logon accounts used for special tasks defined by organizations or when network resources are unavailable). Such accounts remain available and are not subject to automatic disabling or removal dates. Conditions for disabling or deactivating accounts include, for example: (i) when shared/group, emergency, or temporary accounts are no longer required; or (ii) when individuals are transferred or terminated. Some types of information system accounts may require specialized training.", "related": [ "AC-3", "AC-4", "AC-5", "AC-6", "AC-10", "AC-17", "AC-19", "AC-20", "AU-9", "IA-2", "IA-4", "IA-5", "IA-8", "CM-5", "CM-6", "CM-11", "MA-3", "MA-4", "MA-5", "PL-4", "SC-13" ] }, "control-enhancements": { "control-enhancement": [ { "number": "AC-2 (1)", "title": "AUTOMATED SYSTEM ACCOUNT MANAGEMENT", "baseline-impact": [ "MODERATE", "HIGH" ], "statement": { "description": "The organization employs automated mechanisms to support the management of information system accounts." }, "supplemental-guidance": { "description": "The use of automated mechanisms can include, for example: using email or text messaging to automatically notify account managers when users are terminated or transferred; using the information system to monitor account usage; and using telephonic notification to report atypical system account usage." } }, { "number": "AC-2 (2)", "title": "REMOVAL OF TEMPORARY / EMERGENCY ACCOUNTS", "baseline-impact": [ "MODERATE", "HIGH" ], "statement": { "description": "The information system automatically [Selection: removes; disables] temporary and emergency accounts after [Assignment: organization-defined time period for each type of account]." }, "supplemental-guidance": { "description": "This control enhancement requires the removal of both temporary and emergency accounts automatically after a predefined period of time has elapsed, rather than at the convenience of the systems administrator." } }, { "number": "AC-2 (3)", "title": "DISABLE INACTIVE ACCOUNTS", "baseline-impact": [ "MODERATE", "HIGH" ], "statement": { "description": "The information system automatically disables inactive accounts after [Assignment: organization-defined time period]." } }, { "number": "AC-2 (4)", "title": "AUTOMATED AUDIT ACTIONS", "baseline-impact": [ "MODERATE", "HIGH" ], "statement": { "description": "The information system automatically audits account creation, modification, enabling, disabling, and removal actions, and notifies [Assignment: organization-defined personnel or roles]." }, "supplemental-guidance": { "related": [ "AU-2", "AU-12" ] } }, { "number": "AC-2 (5)", "title": "INACTIVITY LOGOUT", "baseline-impact": "HIGH", "statement": { "description": "The organization requires that users log out when [Assignment: organization-defined time-period of expected inactivity or description of when to log out]." }, "supplemental-guidance": { "related": "SC-23" } }, { "number": "AC-2 (6)", "title": "DYNAMIC PRIVILEGE MANAGEMENT", "statement": { "description": "The information system implements the following dynamic privilege management capabilities: [Assignment: organization-defined list of dynamic privilege management capabilities]." }, "supplemental-guidance": { "description": "In contrast to conventional access control approaches which employ static information system accounts and predefined sets of user privileges, dynamic access control approaches (e.g., service-oriented architectures) rely on run time access control decisions facilitated by dynamic privilege management. While user identities may remain relatively constant over time, user privileges may change more frequently based on ongoing mission/business requirements and operational needs of organizations. Dynamic privilege management can include, for example, the immediate revocation of privileges from users, as opposed to requiring that users terminate and restart their sessions to reflect any changes in privileges. Dynamic privilege management can also refer to mechanisms that change the privileges of users based on dynamic rules as opposed to editing specific user profiles. This type of privilege management includes, for example, automatic adjustments of privileges if users are operating out of their normal work times, or if information systems are under duress or in emergency maintenance situations. This control enhancement also includes the ancillary effects of privilege changes, for example, the potential changes to encryption keys used for communications. Dynamic privilege management can support requirements for information system resiliency.", "related": "AC-16" } }, { "number": "AC-2 (7)", "title": "ROLE-BASED SCHEMES", "statement": { "description": "The organization:", "statement": [ { "number": "AC-2 (7)(a)", "description": "Establishes and administers privileged user accounts in accordance with a role-based access scheme that organizes allowed information system access and privileges into roles;" }, { "number": "AC-2 (7)(b)", "description": "Monitors privileged role assignments; and" }, { "number": "AC-2 (7)(c)", "description": "Takes [Assignment: organization-defined actions] when privileged role assignments are no longer appropriate." } ] }, "supplemental-guidance": { "description": "Privileged roles are organization-defined roles assigned to individuals that allow those individuals to perform certain security-relevant functions that ordinary users are not authorized to perform. These privileged roles include, for example, key management, account management, network and system administration, database administration, and web administration." } }, { "number": "AC-2 (8)", "title": "DYNAMIC ACCOUNT CREATION", "statement": { "description": "The information system creates [Assignment: organization-defined information system accounts] dynamically." }, "supplemental-guidance": { "description": "Dynamic approaches for creating information system accounts (e.g., as implemented within service-oriented architectures) rely on establishing accounts (identities) at run time for entities that were previously unknown. Organizations plan for dynamic creation of information system accounts by establishing trust relationships and mechanisms with the appropriate authorities to validate related authorizations and privileges.", "related": "AC-16" } }, { "number": "AC-2 (9)", "title": "RESTRICTIONS ON USE OF SHARED / GROUP ACCOUNTS", "statement": { "description": "The organization only permits the use of shared/group accounts that meet [Assignment: organization-defined conditions for establishing shared/group accounts]." } }, { "number": "AC-2 (10)", "title": "SHARED / GROUP ACCOUNT CREDENTIAL TERMINATION", "statement": { "description": "The information system terminates shared/group account credentials when members leave the group." } }, { "number": "AC-2 (11)", "title": "USAGE CONDITIONS", "baseline-impact": "HIGH", "statement": { "description": "The information system enforces [Assignment: organization-defined circumstances and/or usage conditions] for [Assignment: organization-defined information system accounts]." }, "supplemental-guidance": { "description": "Organizations can describe the specific conditions or circumstances under which information system accounts can be used, for example, by restricting usage to certain days of the week, time of day, or specific durations of time." } }, { "number": "AC-2 (12)", "title": "ACCOUNT MONITORING / ATYPICAL USAGE", "baseline-impact": "HIGH", "statement": { "description": "The organization:", "statement": [ { "number": "AC-2 (12)(a)", "description": "Monitors information system accounts for [Assignment: organization-defined atypical usage]; and" }, { "number": "AC-2 (12)(b)", "description": "Reports atypical usage of information system accounts to [Assignment: organization-defined personnel or roles]." } ] }, "supplemental-guidance": { "description": "Atypical usage includes, for example, accessing information systems at certain times of the day and from locations that are not consistent with the normal usage patterns of individuals working in organizations.", "related": "CA-7" } }, { "number": "AC-2 (13)", "title": "DISABLE ACCOUNTS FOR HIGH-RISK INDIVIDUALS", "baseline-impact": "HIGH", "statement": { "description": "The organization disables accounts of users posing a significant risk within [Assignment: organization-defined time period] of discovery of the risk." }, "supplemental-guidance": { "description": "Users posing a significant risk to organizations include individuals for whom reliable evidence or intelligence indicates either the intention to use authorized access to information systems to cause harm or through whom adversaries will cause harm. Harm includes potential adverse impacts to organizational operations and assets, individuals, other organizations, or the Nation. Close coordination between authorizing officials, information system administrators, and human resource managers is essential in order for timely execution of this control enhancement.", "related": "PS-4" } } ] } }, { "family": "ACCESS CONTROL", "number": "AC-3", "title": "ACCESS ENFORCEMENT", "priority": "P1", "baseline-impact": [ "LOW", "MODERATE", "HIGH" ], "statement": { "description": "The information system enforces approved authorizations for logical access to information and system resources in accordance with applicable access control policies." }, "supplemental-guidance": { "description": "Access control policies (e.g., identity-based policies, role-based policies, control matrices, cryptography) control access between active entities or subjects (i.e., users or processes acting on behalf of users) and passive entities or objects (e.g., devices, files, records, domains) in information systems. In addition to enforcing authorized access at the information system level and recognizing that information systems can host many applications and services in support of organizational missions and business operations, access enforcement mechanisms can also be employed at the application and service level to provide increased information security.", "related": [ "AC-2", "AC-4", "AC-5", "AC-6", "AC-16", "AC-17", "AC-18", "AC-19", "AC-20", "AC-21", "AC-22", "AU-9", "CM-5", "CM-6", "CM-11", "MA-3", "MA-4", "MA-5", "PE-3" ] }, "control-enhancements": { "control-enhancement": [ { "number": "AC-3 (1)", "title": "RESTRICTED ACCESS TO PRIVILEGED FUNCTIONS", "withdrawn": { "incorporated-into": "AC-6" }, "statement": { "description": "[Withdrawn: Incorporated into AC-6]." } }, { "number": "AC-3 (2)", "title": "DUAL AUTHORIZATION", "statement": { "description": "The information system enforces dual authorization for [Assignment: organization-defined privileged commands and/or other organization-defined actions]." }, "supplemental-guidance": { "description": "Dual authorization mechanisms require the approval of two authorized individuals in order to execute. Organizations do not require dual authorization mechanisms when immediate responses are necessary to ensure public and environmental safety. Dual authorization may also be known as two-person control.", "related": [ "CP-9", "MP-6" ] } }, { "number": "AC-3 (3)", "title": "MANDATORY ACCESS CONTROL", "statement": { "description": "The information system enforces [Assignment: organization-defined mandatory access control policy] over all subjects and objects where the policy:", "statement": [ { "number": "AC-3 (3)(a)", "description": "Is uniformly enforced across all subjects and objects within the boundary of the information system;" }, { "number": "AC-3 (3)(b)", "description": "Specifies that a subject that has been granted access to information is constrained from doing any of the following;", "statement": [ { "number": "AC-3 (3)(b)(1)", "description": "Passing the information to unauthorized subjects or objects;" }, { "number": "AC-3 (3)(b)(2)", "description": "Granting its privileges to other subjects;" }, { "number": "AC-3 (3)(b)(3)", "description": "Changing one or more security attributes on subjects, objects, the information system, or information system components;" }, { "number": "AC-3 (3)(b)(4)", "description": "Choosing the security attributes and attribute values to be associated with newly created or modified objects; or" }, { "number": "AC-3 (3)(b)(5)", "description": "Changing the rules governing access control; and" } ] }, { "number": "AC-3 (3)(c)", "description": "Specifies that [Assignment: organization-defined subjects] may explicitly be granted [Assignment: organization-defined privileges (i.e., they are trusted subjects)] such that they are not limited by some or all of the above constraints." } ] }, "supplemental-guidance": { "description": "Mandatory access control as defined in this control enhancement is synonymous with nondiscretionary access control, and is not constrained only to certain historical uses (e.g., implementations using the Bell-LaPadula Model). The above class of mandatory access control policies constrains what actions subjects can take with information obtained from data objects for which they have already been granted access, thus preventing the subjects from passing the information to unauthorized subjects and objects. This class of mandatory access control policies also constrains what actions subjects can take with respect to the propagation of access control privileges; that is, a subject with a privilege cannot pass that privilege to other subjects. The policy is uniformly enforced over all subjects and objects to which the information system has control. Otherwise, the access control policy can be circumvented. This enforcement typically is provided via an implementation that meets the reference monitor concept (see AC-25). The policy is bounded by the information system boundary (i.e., once the information is passed outside of the control of the system, additional means may be required to ensure that the constraints on the information remain in effect). The trusted subjects described above are granted privileges consistent with the concept of least privilege (see AC-6). Trusted subjects are only given the minimum privileges relative to the above policy necessary for satisfying organizational mission/business needs. The control is most applicable when there is some policy mandate (e.g., law, Executive Order, directive, or regulation) that establishes a policy regarding access to sensitive/classified information and some users of the information system are not authorized access to all sensitive/classified information resident in the information system. This control can operate in conjunction with AC-3 (4). A subject that is constrained in its operation by policies governed by this control is still able to operate under the less rigorous constraints of AC-3 (4), but policies governed by this control take precedence over the less rigorous constraints of AC-3 (4). For example, while a mandatory access control policy imposes a constraint preventing a subject from passing information to another subject operating at a different sensitivity label, AC-3 (4) permits the subject to pass the information to any subject with the same sensitivity label as the subject.", "related": [ "AC-25", "SC-11" ] } }, { "number": "AC-3 (4)", "title": "DISCRETIONARY ACCESS CONTROL", "statement": { "description": "The information system enforces [Assignment: organization-defined discretionary access control policy] over defined subjects and objects where the policy specifies that a subject that has been granted access to information can do one or more of the following:", "statement": [ { "number": "AC-3 (4)(a)", "description": "Pass the information to any other subjects or objects;" }, { "number": "AC-3 (4)(b)", "description": "Grant its privileges to other subjects;" }, { "number": "AC-3 (4)(c)", "description": "Change security attributes on subjects, objects, the information system, or the information system�s components;" }, { "number": "AC-3 (4)(d)", "description": "Choose the security attributes to be associated with newly created or revised objects; or" }, { "number": "AC-3 (4)(e)", "description": "Change the rules governing access control." } ] }, "supplemental-guidance": { "description": "When discretionary access control policies are implemented, subjects are not constrained with regard to what actions they can take with information for which they have already been granted access. Thus, subjects that have been granted access to information are not prevented from passing (i.e., the subjects have the discretion to pass) the information to other subjects or objects. This control enhancement can operate in conjunction with AC-3 (3). A subject that is constrained in its operation by policies governed by AC-3 (3) is still able to operate under the less rigorous constraints of this control enhancement. Thus, while AC-3 (3) imposes constraints preventing a subject from passing information to another subject operating at a different sensitivity level, AC-3 (4) permits the subject to pass the information to any subject at the same sensitivity level. The policy is bounded by the information system boundary. Once the information is passed outside of the control of the information system, additional means may be required to ensure that the constraints remain in effect. While the older, more traditional definitions of discretionary access control require identity-based access control, that limitation is not required for this use of discretionary access control." } }, { "number": "AC-3 (5)", "title": "SECURITY-RELEVANT INFORMATION", "statement": { "description": "The information system prevents access to [Assignment: organization-defined security-relevant information] except during secure, non-operable system states." }, "supplemental-guidance": { "description": "Security-relevant information is any information within information systems that can potentially impact the operation of security functions or the provision of security services in a manner that could result in failure to enforce system security policies or maintain the isolation of code and data. Security-relevant information includes, for example, filtering rules for routers/firewalls, cryptographic key management information, configuration parameters for security services, and access control lists. Secure, non-operable system states include the times in which information systems are not performing mission/business-related processing (e.g., the system is off-line for maintenance, troubleshooting, boot-up, shut down).", "related": "CM-3" } }, { "number": "AC-3 (6)", "title": "PROTECTION OF USER AND SYSTEM INFORMATION", "withdrawn": { "incorporated-into": [ "MP-4", "SC-28" ] }, "statement": { "description": "[Withdrawn: Incorporated into MP-4 and SC-28]." } }, { "number": "AC-3 (7)", "title": "ROLE-BASED ACCESS CONTROL", "statement": { "description": "The information system enforces a role-based access control policy over defined subjects and objects and controls access based upon [Assignment: organization-defined roles and users authorized to assume such roles]." }, "supplemental-guidance": { "description": "Role-based access control (RBAC) is an access control policy that restricts information system access to authorized users. Organizations can create specific roles based on job functions and the authorizations (i.e., privileges) to perform needed operations on organizational information systems associated with the organization-defined roles. When users are assigned to the organizational roles, they inherit the authorizations or privileges defined for those roles. RBAC simplifies privilege administration for organizations because privileges are not assigned directly to every user (which can be a significant number of individuals for mid- to large-size organizations) but are instead acquired through role assignments. RBAC can be implemented either as a mandatory or discretionary form of access control. For organizations implementing RBAC with mandatory access controls, the requirements in AC-3 (3) define the scope of the subjects and objects covered by the policy." } }, { "number": "AC-3 (8)", "title": "REVOCATION OF ACCESS AUTHORIZATIONS", "statement": { "description": "The information system enforces the revocation of access authorizations resulting from changes to the security attributes of subjects and objects based on [Assignment: organization-defined rules governing the timing of revocations of access authorizations]." }, "supplemental-guidance": { "description": "Revocation of access rules may differ based on the types of access revoked. For example, if a subject (i.e., user or process) is removed from a group, access may not be revoked until the next time the object (e.g., file) is opened or until the next time the subject attempts a new access to the object. Revocation based on changes to security labels may take effect immediately. Organizations can provide alternative approaches on how to make revocations immediate if information systems cannot provide such capability and immediate revocation is necessary." } }, { "number": "AC-3 (9)", "title": "CONTROLLED RELEASE", "statement": { "description": "The information system does not release information outside of the established system boundary unless:", "statement": [ { "number": "AC-3 (9)(a)", "description": "The receiving [Assignment: organization-defined information system or system component] provides [Assignment: organization-defined security safeguards]; and" }, { "number": "AC-3 (9)(b)", "description": "[Assignment: organization-defined security safeguards] are used to validate the appropriateness of the information designated for release." } ] }, "supplemental-guidance": { "description": "Information systems can only protect organizational information within the confines of established system boundaries. Additional security safeguards may be needed to ensure that such information is adequately protected once it is passed beyond the established information system boundaries. Examples of information leaving the system boundary include transmitting information to an external information system or printing the information on one of its printers. In cases where the information system is unable to make a determination of the adequacy of the protections provided by entities outside its boundary, as a mitigating control, organizations determine procedurally whether the external information systems are providing adequate security. The means used to determine the adequacy of the security provided by external information systems include, for example, conducting inspections or periodic testing, establishing agreements between the organization and its counterpart organizations, or some other process. The means used by external entities to protect the information received need not be the same as those used by the organization, but the means employed are sufficient to provide consistent adjudication of the security policy to protect the information. This control enhancement requires information systems to employ technical or procedural means to validate the information prior to releasing it to external systems. For example, if the information system passes information to another system controlled by another organization, technical means are employed to validate that the security attributes associated with the exported information are appropriate for the receiving system. Alternatively, if the information system passes information to a printer in organization-controlled space, procedural means can be employed to ensure that only appropriately authorized individuals gain access to the printer. This control enhancement is most applicable when there is some policy mandate (e.g., law, Executive Order, directive, or regulation) that establishes policy regarding access to the information, and that policy applies beyond the realm of a particular information system or organization." } }, { "number": "AC-3 (10)", "title": "AUDITED OVERRIDE OF ACCESS CONTROL MECHANISMS", "statement": { "description": "The organization employs an audited override of automated access control mechanisms under [Assignment: organization-defined conditions]." }, "supplemental-guidance": { "related": [ "AU-2", "AU-6" ] } } ] } }, { "family": "ACCESS CONTROL", "number": "AC-4", "title": "INFORMATION FLOW ENFORCEMENT", "priority": "P1", "baseline-impact": [ "MODERATE", "HIGH" ], "statement": { "description": "The information system enforces approved authorizations for controlling the flow of information within the system and between interconnected systems based on [Assignment: organization-defined information flow control policies]." }, "supplemental-guidance": { "description": "Information flow control regulates where information is allowed to travel within an information system and between information systems (as opposed to who is allowed to access the information) and without explicit regard to subsequent accesses to that information. Flow control restrictions include, for example, keeping export-controlled information from being transmitted in the clear to the Internet, blocking outside traffic that claims to be from within the organization, restricting web requests to the Internet that are not from the internal web proxy server, and limiting information transfers between organizations based on data structures and content. Transferring information between information systems representing different security domains with different security policies introduces risk that such transfers violate one or more domain security policies. In such situations, information owners/stewards provide guidance at designated policy enforcement points between interconnected systems. Organizations consider mandating specific architectural solutions when required to enforce specific security policies. Enforcement includes, for example: (i) prohibiting information transfers between interconnected systems (i.e., allowing access only); (ii) employing hardware mechanisms to enforce one-way information flows; and (iii) implementing trustworthy regrading mechanisms to reassign security attributes and security labels.\nOrganizations commonly employ information flow control policies and enforcement mechanisms to control the flow of information between designated sources and destinations (e.g., networks, individuals, and devices) within information systems and between interconnected systems. Flow control is based on the characteristics of the information and/or the information path. Enforcement occurs, for example, in boundary protection devices (e.g., gateways, routers, guards, encrypted tunnels, firewalls) that employ rule sets or establish configuration settings that restrict information system services, provide a packet-filtering capability based on header information, or message-filtering capability based on message content (e.g., implementing key word searches or using document characteristics). Organizations also consider the trustworthiness of filtering/inspection mechanisms (i.e., hardware, firmware, and software components) that are critical to information flow enforcement. Control enhancements 3 through 22 primarily address cross-domain solution needs which focus on more advanced filtering techniques, in-depth analysis, and stronger flow enforcement mechanisms implemented in cross-domain products, for example, high-assurance guards. Such capabilities are generally not available in commercial off-the-shelf information technology products.", "related": [ "AC-3", "AC-17", "AC-19", "AC-21", "CM-6", "CM-7", "SA-8", "SC-2", "SC-5", "SC-7", "SC-18" ] }, "control-enhancements": { "control-enhancement": [ { "number": "AC-4 (1)", "title": "OBJECT SECURITY ATTRIBUTES", "statement": { "description": "The information system uses [Assignment: organization-defined security attributes] associated with [Assignment: organization-defined information, source, and destination objects] to enforce [Assignment: organization-defined information flow control policies] as a basis for flow control decisions." }, "supplemental-guidance": { "description": "Information flow enforcement mechanisms compare security attributes associated with information (data content and data structure) and source/destination objects, and respond appropriately (e.g., block, quarantine, alert administrator) when the mechanisms encounter information flows not explicitly allowed by information flow policies. For example, an information object labeled Secret would be allowed to flow to a destination object labeled Secret, but an information object labeled Top Secret would not be allowed to flow to a destination object labeled Secret. Security attributes can also include, for example, source and destination addresses employed in traffic filter firewalls. Flow enforcement using explicit security attributes can be used, for example, to control the release of certain types of information.", "related": "AC-16" } }, { "number": "AC-4 (2)", "title": "PROCESSING DOMAINS", "statement": { "description": "The information system uses protected processing domains to enforce [Assignment: organization-defined information flow control policies] as a basis for flow control decisions." }, "supplemental-guidance": { "description": "Within information systems, protected processing domains are processing spaces that have controlled interactions with other processing spaces, thus enabling control of information flows between these spaces and to/from data/information objects. A protected processing domain can be provided, for example, by implementing domain and type enforcement. In domain and type enforcement, information system processes are assigned to domains; information is identified by types; and information flows are controlled based on allowed information accesses (determined by domain and type), allowed signaling among domains, and allowed process transitions to other domains." } }, { "number": "AC-4 (3)", "title": "DYNAMIC INFORMATION FLOW CONTROL", "statement": { "description": "The information system enforces dynamic information flow control based on [Assignment: organization-defined policies]." }, "supplemental-guidance": { "description": "Organizational policies regarding dynamic information flow control include, for example, allowing or disallowing information flows based on changing conditions or mission/operational considerations. Changing conditions include, for example, changes in organizational risk tolerance due to changes in the immediacy of mission/business needs, changes in the threat environment, and detection of potentially harmful or adverse events.", "related": "SI-4" } }, { "number": "AC-4 (4)", "title": "CONTENT CHECK ENCRYPTED INFORMATION", "statement": { "description": "The information system prevents encrypted information from bypassing content-checking mechanisms by [Selection (one or more): decrypting the information; blocking the flow of the encrypted information; terminating communications sessions attempting to pass encrypted information; [Assignment: organization-defined procedure or method]]." }, "supplemental-guidance": { "related": "SI-4" } }, { "number": "AC-4 (5)", "title": "EMBEDDED DATA TYPES", "statement": { "description": "The information system enforces [Assignment: organization-defined limitations] on embedding data types within other data types." }, "supplemental-guidance": { "description": "Embedding data types within other data types may result in reduced flow control effectiveness. Data type embedding includes, for example, inserting executable files as objects within word processing files, inserting references or descriptive information into a media file, and compressed or archived data types that may include multiple embedded data types. Limitations on data type embedding consider the levels of embedding and prohibit levels of data type embedding that are beyond the capability of the inspection tools." } }, { "number": "AC-4 (6)", "title": "METADATA", "statement": { "description": "The information system enforces information flow control based on [Assignment: organization-defined metadata]." }, "supplemental-guidance": { "description": "Metadata is information used to describe the characteristics of data. Metadata can include structural metadata describing data structures (e.g., data format, syntax, and semantics) or descriptive metadata describing data contents (e.g., age, location, telephone number). Enforcing allowed information flows based on metadata enables simpler and more effective flow control. Organizations consider the trustworthiness of metadata with regard to data accuracy (i.e., knowledge that the metadata values are correct with respect to the data), data integrity (i.e., protecting against unauthorized changes to metadata tags), and the binding of metadata to the data payload (i.e., ensuring sufficiently strong binding techniques with appropriate levels of assurance).", "related": [ "AC-16", "SI-7" ] } }, { "number"