Knowledge is Power

Sitewide Search

Search Bare Metal Cyber

Search courses, individual lessons, wiki entries, books, podcasts, magazine articles, Daily Cyber News, and Darwin.

NIST SP 800-53 Learning Center

SC — System and Communications Protection

Study this control family as a connected set of risk outcomes, implementation decisions, evidence expectations, and assessment questions.

51Base controls
111Enhancements
162Family records
23Withdrawn records

Control family

System and Communications Protection

Use the family as a planning boundary, but assess each selected control against the system context, inherited services, organization-defined parameters, and evidence available from real operations.

51 base controls111 enhancementsRelease 5.2.0
SC

Family catalog

Search System and Communications Protection controls.

Base controls open full profiles. Enhancement results link directly to the corresponding enhancement section on the parent control page.

SC-1control

Policy and Procedures

System and communications protection policy and procedures address the controls in the SC family that are implemented within systems and organizations. The risk management strategy is an important factor in establishing such policies and procedures. Policies and procedures contribute to security and privacy assurance. Therefore, it is important that security

SC-2control

Separation of System and User Functionality

System management functionality includes functions that are necessary to administer databases, network components, workstations, or servers. These functions typically require privileged user access. The separation of user functions from system management functions is physical or logical. Organizations may separate system management functions from user functi

SC-3control

Security Function Isolation

Security functions are isolated from nonsecurity functions by means of an isolation boundary implemented within a system via partitions and domains. The isolation boundary controls access to and protects the integrity of the hardware, software, and firmware that perform system security functions. Systems implement code separation in many ways, such as throug

SC-4control

Information in Shared System Resources

Preventing unauthorized and unintended information transfer via shared system resources stops information produced by the actions of prior users or roles (or the actions of processes acting on behalf of prior users or roles) from being available to current users or roles (or current processes acting on behalf of current users or roles) that obtain access to

SC-5control

Denial-of-service Protection

Denial-of-service events may occur due to a variety of internal and external causes, such as an attack by an adversary or a lack of planning to support organizational needs with respect to capacity and bandwidth. Such attacks can occur across a wide range of network protocols (e.g., IPv4, IPv6). A variety of technologies are available to limit or eliminate t

SC-6control

Resource Availability

Priority protection prevents lower-priority processes from delaying or interfering with the system that services higher-priority processes. Quotas prevent users or processes from obtaining more than predetermined amounts of resources.

SC-7control

Boundary Protection

Managed interfaces include gateways, routers, firewalls, guards, network-based malicious code analysis, virtualization systems, or encrypted tunnels implemented within a security architecture. Subnetworks that are physically or logically separated from internal networks are referred to as demilitarized zones or DMZs. Restricting or prohibiting interfaces wit

SC-8control

Transmission Confidentiality and Integrity

Protecting the confidentiality and integrity of transmitted information applies to internal and external networks as well as any system components that can transmit information, including servers, notebook computers, desktop computers, mobile devices, printers, copiers, scanners, facsimile machines, and radios. Unprotected communication paths are exposed to

SC-10control

Network Disconnect

Network disconnect applies to internal and external networks. Terminating network connections associated with specific communications sessions includes de-allocating TCP/IP address or port pairs at the operating system level and de-allocating the networking assignments at the application level if multiple application sessions are using a single operating sys

SC-11control

Trusted Path

Trusted paths are mechanisms by which users can communicate (using input devices such as keyboards) directly with the security functions of systems with the requisite assurance to support security policies. Trusted path mechanisms can only be activated by users or the security functions of organizational systems. User responses that occur via trusted paths a

SC-12control

Cryptographic Key Establishment and Management

Cryptographic key management and establishment can be performed using manual procedures or automated mechanisms with supporting manual procedures. Organizations define key management requirements in accordance with applicable laws, executive orders, directives, regulations, policies, standards, and guidelines and specify appropriate options, parameters, and

SC-13control

Cryptographic Protection

Cryptography can be employed to support a variety of security solutions, including the protection of classified information and controlled unclassified information, the provision and implementation of digital signatures, and the enforcement of information separation when authorized individuals have the necessary clearances but lack the necessary formal acces

SC-15control

Collaborative Computing Devices and Applications

Collaborative computing devices and applications include remote meeting devices and applications, networked white boards, cameras, and microphones. The explicit indication of use includes signals to users when collaborative computing devices and applications are activated.

SC-16control

Transmission of Security and Privacy Attributes

Security and privacy attributes can be explicitly or implicitly associated with the information contained in organizational systems or system components. Attributes are abstractions that represent the basic properties or characteristics of an entity with respect to protecting information or the management of personally identifiable information. Attributes ar

SC-17control

Public Key Infrastructure Certificates

Public key infrastructure (PKI) certificates are certificates with visibility external to organizational systems and certificates related to the internal operations of systems, such as application-specific time services. In cryptographic systems with a hierarchical structure, a trust anchor is an authoritative source (i.e., a certificate authority) for which

SC-18control

Mobile Code

Mobile code includes any program, application, or content that can be transmitted across a network (e.g., embedded in an email, document, or website) and executed on a remote system. Decisions regarding the use of mobile code within organizational systems are based on the potential for the code to cause damage to the systems if used maliciously. Mobile code

SC-20control

Secure Name/Address Resolution Service (Authoritative Source)

Providing authoritative source information enables external clients, including remote Internet clients, to obtain origin authentication and integrity verification assurances for the host/service name to network address resolution information obtained through the service. Systems that provide name and address resolution services include domain name system (DN

SC-2(1)enhancement

Interfaces for Non-privileged Users

Preventing the presentation of system management functionality at interfaces to non-privileged users ensures that system administration options, including administrator privileges, are not available to the general user population. Restricting user access also prohibits the use of the grey-out option commonly used to eliminate accessibility to such informatio

SC-21control

Secure Name/Address Resolution Service (Recursive or Caching Resolver)

Each client of name resolution services either performs this validation on its own or has authenticated channels to trusted validation providers. Systems that provide name and address resolution services for local clients include recursive resolving or caching domain name system (DNS) servers. DNS client resolvers either perform validation of DNSSEC signatur

SC-2(2)enhancement

Disassociability

If a system is compromised, storing applications and software separately from state information about users’ interactions with an application may better protect individuals’ privacy.

SC-22control

Architecture and Provisioning for Name/Address Resolution Service

Systems that provide name and address resolution services include domain name system (DNS) servers. To eliminate single points of failure in systems and enhance redundancy, organizations employ at least two authoritative domain name system servers—one configured as the primary server and the other configured as the secondary server. Additionally, organizatio

SC-23control

Session Authenticity

Protecting session authenticity addresses communications protection at the session level, not at the packet level. Such protection establishes grounds for confidence at both ends of communications sessions in the ongoing identities of other parties and the validity of transmitted information. Authenticity protection includes protecting against "man-in-the-mi

SC-24control

Fail in Known State

Failure in a known state addresses security concerns in accordance with the mission and business needs of organizations. Failure in a known state prevents the loss of confidentiality, integrity, or availability of information in the event of failures of organizational systems or system components. Failure in a known safe state helps to prevent systems from f

SC-25control

Thin Nodes

The deployment of system components with minimal functionality reduces the need to secure every endpoint and may reduce the exposure of information, systems, and services to attacks. Reduced or minimal functionality includes diskless nodes and thin client technologies.

SC-26control

Decoys

Decoys (i.e., honeypots, honeynets, or deception nets) are established to attract adversaries and deflect attacks away from the operational systems that support organizational mission and business functions. Use of decoys requires some supporting isolation measures to ensure that any deflected malicious code does not infect organizational systems. Depending

SC-27control

Platform-independent Applications

Platforms are combinations of hardware, firmware, and software components used to execute software applications. Platforms include operating systems, the underlying computer architectures, or both. Platform-independent applications are applications with the capability to execute on multiple platforms. Such applications promote portability and reconstitution

SC-28control

Protection of Information at Rest

Information at rest refers to the state of information when it is not in process or in transit and is located on system components. Such components include internal or external hard disk drives, storage area network devices, or databases. However, the focus of protecting information at rest is not on the type of storage device or frequency of access but rath

SC-29control

Heterogeneity

Increasing the diversity of information technologies within organizational systems reduces the impact of potential exploitations or compromises of specific technologies. Such diversity protects against common mode failures, including those failures induced by supply chain attacks. Diversity in information technologies also reduces the likelihood that the mea

SC-30control

Concealment and Misdirection

Concealment and misdirection techniques can significantly reduce the targeting capabilities of adversaries (i.e., window of opportunity and available attack surface) to initiate and complete attacks. For example, virtualization techniques provide organizations with the ability to disguise systems, potentially reducing the likelihood of successful attacks wit

SC-3(1)enhancement

Hardware Separation

Hardware separation mechanisms include hardware ring architectures that are implemented within microprocessors and hardware-enforced address segmentation used to support logically distinct storage objects with separate attributes (i.e., readable, writeable).

SC-31control

Covert Channel Analysis

Developers are in the best position to identify potential areas within systems that might lead to covert channels. Covert channel analysis is a meaningful activity when there is the potential for unauthorized information flows across security domains, such as in the case of systems that contain export-controlled information and have connections to external n

SC-3(2)enhancement

Access and Flow Control Functions

Security function isolation occurs because of implementation. The functions can still be scanned and monitored. Security functions that are potentially isolated from access and flow control enforcement functions include auditing, intrusion detection, and malicious code protection functions.

SC-32control

System Partitioning

System partitioning is part of a defense-in-depth protection strategy. Organizations determine the degree of physical separation of system components. Physical separation options include physically distinct components in separate racks in the same room, critical components in separate rooms, and geographical separation of critical components. Security catego

SC-3(3)enhancement

Minimize Nonsecurity Functionality

Where it is not feasible to achieve strict isolation of nonsecurity functions from security functions, it is necessary to take actions to minimize nonsecurity-relevant functions within the security function boundary. Nonsecurity functions contained within the isolation boundary are considered security-relevant because errors or malicious code in the software

SC-3(4)enhancement

Module Coupling and Cohesiveness

The reduction of inter-module interactions helps to constrain security functions and manage complexity. The concepts of coupling and cohesion are important with respect to modularity in software design. Coupling refers to the dependencies that one module has on other modules. Cohesion refers to the relationship between functions within a module. Best practic

SC-34control

Non-modifiable Executable Programs

The operating environment for a system contains the code that hosts applications, including operating systems, executives, or virtual machine monitors (i.e., hypervisors). It can also include certain applications that run directly on hardware platforms. Hardware-enforced, read-only media include Compact Disc-Recordable (CD-R) and Digital Versatile Disc-Recor

SC-3(5)enhancement

Layered Structures

The implementation of layered structures with minimized interactions among security functions and non-looping layers (i.e., lower-layer functions do not depend on higher-layer functions) enables the isolation of security functions and the management of complexity.

SC-35control

External Malicious Code Identification

External malicious code identification differs from decoys in [SC-26](#sc-26) in that the components actively probe networks, including the Internet, in search of malicious code contained on external websites. Like decoys, the use of external malicious code identification techniques requires some supporting isolation measures to ensure that any malicious cod

SC-36control

Distributed Processing and Storage

Distributing processing and storage across multiple physical locations or logical domains provides a degree of redundancy or overlap for organizations. The redundancy and overlap increase the work factor of adversaries to adversely impact organizational operations, assets, and individuals. The use of distributed processing and storage does not assume a singl

SC-37control

Out-of-band Channels

Out-of-band channels include local, non-network accesses to systems; network paths physically separate from network paths used for operational traffic; or non-electronic paths, such as the U.S. Postal Service. The use of out-of-band channels is contrasted with the use of in-band channels (i.e., the same channels) that carry routine operational traffic. Out-o

SC-38control

Operations Security

Operations security (OPSEC) is a systematic process by which potential adversaries can be denied information about the capabilities and intentions of organizations by identifying, controlling, and protecting generally unclassified information that specifically relates to the planning and execution of sensitive organizational activities. The OPSEC process inv

SC-39control

Process Isolation

Systems can maintain separate execution domains for each executing process by assigning each process a separate address space. Each system process has a distinct address space so that communication between processes is performed in a manner controlled through the security functions, and one process cannot modify the executing code of another process. Maintai

SC-40control

Wireless Link Protection

Wireless link protection applies to internal and external wireless communication links that may be visible to individuals who are not authorized system users. Adversaries can exploit the signal parameters of wireless links if such links are not adequately protected. There are many ways to exploit the signal parameters of wireless links to gain intelligence,

SC-41control

Port and I/O Device Access

Connection ports include Universal Serial Bus (USB), Thunderbolt, and Firewire (IEEE 1394). Input/output (I/O) devices include compact disc and digital versatile disc drives. Disabling or removing such connection ports and I/O devices helps prevent the exfiltration of information from systems and the introduction of malicious code from those ports or devices

SC-4(2)enhancement

Multilevel or Periods Processing

Changes in processing levels can occur during multilevel or periods processing with information at different classification levels or security categories. It can also occur during serial reuse of hardware components at different classification levels. Organization-defined procedures can include approved sanitization processes for electronically stored inform

SC-42control

Sensor Capability and Data

Sensor capability and data applies to types of systems or system components characterized as mobile devices, such as cellular telephones, smart phones, and tablets. Mobile devices often include sensors that can collect and record data regarding the environment where the system is in use. Sensors that are embedded within mobile devices include microphones, ca

SC-43control

Usage Restrictions

Usage restrictions apply to all system components including but not limited to mobile code, mobile devices, wireless access, and wired and wireless peripheral components (e.g., copiers, printers, scanners, optical devices, and other similar technologies). The usage restrictions and implementation guidelines are based on the potential for system components to

SC-44control

Detonation Chambers

Detonation chambers, also known as dynamic execution environments, allow organizations to open email attachments, execute untrusted or suspicious applications, and execute Universal Resource Locator requests in the safety of an isolated environment or a virtualized sandbox. Protected and isolated execution environments provide a means of determining whether

SC-45control

System Time Synchronization

Time synchronization of system clocks is essential for the correct execution of many system services, including identification and authentication processes that involve certificates and time-of-day restrictions as part of access control. Denial of service or failure to deny expired credentials may result without properly synchronized clocks within and betwee

SC-46control

Cross Domain Policy Enforcement

For logical policy enforcement mechanisms, organizations avoid creating a logical path between interfaces to prevent the ability to bypass the policy enforcement mechanism. For physical policy enforcement mechanisms, the robustness of physical isolation afforded by the physical implementation of policy enforcement to preclude the presence of logical covert c

SC-47control

Alternate Communications Paths

An incident, whether adversarial- or nonadversarial-based, can disrupt established communications paths used for system operations and organizational command and control. Alternate communications paths reduce the risk of all communications paths being affected by the same incident. To compound the problem, the inability of organizational officials to obtain

SC-48control

Sensor Relocation

Adversaries may take various paths and use different approaches as they move laterally through an organization (including its systems) to reach their target or as they attempt to exfiltrate information from the organization. The organization often only has a limited set of monitoring and detection capabilities, and they may be focused on the critical or like

SC-49control

Hardware-enforced Separation and Policy Enforcement

System owners may require additional strength of mechanism and robustness to ensure domain separation and policy enforcement for specific types of threats and environments of operation. Hardware-enforced separation and policy enforcement provide greater strength of mechanism than software-enforced separation and policy enforcement.

SC-5(1)enhancement

Restrict Ability to Attack Other Systems

Restricting the ability of individuals to launch denial-of-service attacks requires the mechanisms commonly used for such attacks to be unavailable. Individuals of concern include hostile insiders or external adversaries who have breached or compromised the system and are using it to launch a denial-of-service attack. Organizations can restrict the ability o

SC-5(2)enhancement

Capacity, Bandwidth, and Redundancy

Managing capacity ensures that sufficient capacity is available to counter flooding attacks. Managing capacity includes establishing selected usage priorities, quotas, partitioning, or load balancing.

SC-5(3)enhancement

Detection and Monitoring

Organizations consider the utilization and capacity of system resources when managing risk associated with a denial of service due to malicious attacks. Denial-of-service attacks can originate from external or internal sources. System resources that are sensitive to denial of service include physical disk storage, memory, and CPU cycles. Techniques used to p

SC-7(3)enhancement

Access Points

Limiting the number of external network connections facilitates monitoring of inbound and outbound communications traffic. The Trusted Internet Connection [DHS TIC](#4f42ee6e-86cc-403b-a51f-76c2b4f81b54) initiative is an example of a federal guideline that requires limits on the number of external network connections. Limiting the number of external network

SC-7(4)enhancement

External Telecommunications Services

External telecommunications services can provide data and/or voice communications services. Examples of control plane traffic include Border Gateway Protocol (BGP) routing, Domain Name System (DNS), and management protocols. See [SP 800-189](#f5edfe51-d1f2-422e-9b27-5d0e90b49c72) for additional information on the use of the resource public key infrastructure

SC-7(5)enhancement

Deny by Default — Allow by Exception

Denying by default and allowing by exception applies to inbound and outbound network communications traffic. A deny-all, permit-by-exception network communications traffic policy ensures that only those system connections that are essential and approved are allowed. Deny by default, allow by exception also applies to a system that is connected to an external

SC-7(7)enhancement

Split Tunneling for Remote Devices

Split tunneling is the process of allowing a remote user or device to establish a non-remote connection with a system and simultaneously communicate via some other connection to a resource in an external network. This method of network access enables a user to access remote devices and simultaneously, access uncontrolled networks. Split tunneling might be de

SC-7(8)enhancement

Route Traffic to Authenticated Proxy Servers

External networks are networks outside of organizational control. A proxy server is a server (i.e., system or application) that acts as an intermediary for clients requesting system resources from non-organizational or other organizational servers. System resources that may be requested include files, connections, web pages, or services. Client requests esta

SC-7(9)enhancement

Restrict Threatening Outgoing Communications Traffic

Detecting outgoing communications traffic from internal actions that may pose threats to external systems is known as extrusion detection. Extrusion detection is carried out within the system at managed interfaces. Extrusion detection includes the analysis of incoming and outgoing communications traffic while searching for indications of internal threats to

SC-8(1)enhancement

Cryptographic Protection

Encryption protects information from unauthorized disclosure and modification during transmission. Cryptographic mechanisms that protect the confidentiality and integrity of information during transmission include TLS and IPSec. Cryptographic mechanisms used to protect information integrity include cryptographic hash functions that have applications in digit

SC-8(2)enhancement

Pre- and Post-transmission Handling

Information can be unintentionally or maliciously disclosed or modified during preparation for transmission or during reception, including during aggregation, at protocol transformation points, and during packing and unpacking. Such unauthorized disclosures or modifications compromise the confidentiality or integrity of the information.

SC-8(3)enhancement

Cryptographic Protection for Message Externals

Cryptographic protection for message externals addresses protection from the unauthorized disclosure of information. Message externals include message headers and routing information. Cryptographic protection prevents the exploitation of message externals and applies to internal and external networks or links that may be visible to individuals who are not au

SC-8(4)enhancement

Conceal or Randomize Communications

Concealing or randomizing communication patterns addresses protection from unauthorized disclosure of information. Communication patterns include frequency, periods, predictability, and amount. Changes to communications patterns can reveal information with intelligence value, especially when combined with other available information related to the mission an

SC-8(5)enhancement

Protected Distribution System

The purpose of a protected distribution system is to deter, detect, and/or make difficult physical access to the communication lines that carry national security information.

SC-11(1)enhancement

Irrefutable Communications Path

An irrefutable communications path permits the system to initiate a trusted path, which necessitates that the user can unmistakably recognize the source of the communication as a trusted system component. For example, the trusted path may appear in an area of the display that other applications cannot access or be based on the presence of an identifier that

SC-12(1)enhancement

Availability

Escrowing of encryption keys is a common practice for ensuring availability in the event of key loss. A forgotten passphrase is an example of losing a cryptographic key.

SC-12(2)enhancement

Symmetric Keys

[SP 800-56A](#20957dbb-6a1e-40a2-b38a-66f67d33ac2e), [SP 800-56B](#0d083d8a-5cc6-46f1-8d79-3081d42bcb75) , and [SP 800-56C](#eef62b16-c796-4554-955c-505824135b8a) provide guidance on cryptographic key establishment schemes and key derivation methods. [SP 800-57-1](#110e26af-4765-49e1-8740-6750f83fcda1), [SP 800-57-2](#e7942589-e267-4a5a-a3d9-f39a7aae81f0) ,

SC-12(3)enhancement

Asymmetric Keys

[SP 800-56A](#20957dbb-6a1e-40a2-b38a-66f67d33ac2e), [SP 800-56B](#0d083d8a-5cc6-46f1-8d79-3081d42bcb75) , and [SP 800-56C](#eef62b16-c796-4554-955c-505824135b8a) provide guidance on cryptographic key establishment schemes and key derivation methods. [SP 800-57-1](#110e26af-4765-49e1-8740-6750f83fcda1), [SP 800-57-2](#e7942589-e267-4a5a-a3d9-f39a7aae81f0) ,

SC-12(6)enhancement

Physical Control of Keys

For organizations that use external service providers (e.g., cloud service or data center providers), physical control of cryptographic keys provides additional assurance that information stored by such external providers is not subject to unauthorized disclosure or modification.

SC-15(1)enhancement

Physical or Logical Disconnect

Failing to disconnect from collaborative computing devices can result in subsequent compromises of organizational information. Providing easy methods to disconnect from such devices after a collaborative computing session ensures that participants carry out the disconnect activity without having to go through complex and tedious procedures. Disconnect from c

SC-15(3)enhancement

Disabling and Removal in Secure Work Areas

Failing to disable or remove collaborative computing devices and applications from systems or system components can result in compromises of information, including eavesdropping on conversations. A Sensitive Compartmented Information Facility (SCIF) is an example of a secure work area.

SC-15(4)enhancement

Explicitly Indicate Current Participants

Explicitly indicating current participants prevents unauthorized individuals from participating in collaborative computing sessions without the explicit knowledge of other participants.

SC-16(1)enhancement

Integrity Verification

Part of verifying the integrity of transmitted information is ensuring that security and privacy attributes that are associated with such information have not been modified in an unauthorized manner. Unauthorized modification of security or privacy attributes can result in a loss of integrity for transmitted information.

SC-16(2)enhancement

Anti-spoofing Mechanisms

Some attack vectors operate by altering the security attributes of an information system to intentionally and maliciously implement an insufficient level of security within the system. The alteration of attributes leads organizations to believe that a greater number of security functions are in place and operational than have actually been implemented.

SC-16(3)enhancement

Cryptographic Binding

Cryptographic mechanisms and techniques can provide strong security and privacy attribute binding to transmitted information to help ensure the integrity of such information.

SC-18(1)enhancement

Identify Unacceptable Code and Take Corrective Actions

Corrective actions when unacceptable mobile code is detected include blocking, quarantine, or alerting administrators. Blocking includes preventing the transmission of word processing files with embedded macros when such macros have been determined to be unacceptable mobile code.

SC-18(4)enhancement

Prevent Automatic Execution

Actions enforced before executing mobile code include prompting users prior to opening email attachments or clicking on web links. Preventing the automatic execution of mobile code includes disabling auto-execute features on system components that employ portable storage devices, such as compact discs, digital versatile discs, and universal serial bus device

SC-23(3)enhancement

Unique System-generated Session Identifiers

Generating unique session identifiers curtails the ability of adversaries to reuse previously valid session IDs. Employing the concept of randomness in the generation of unique session identifiers protects against brute-force attacks to determine future session identifiers.

SC-23(5)enhancement

Allowed Certificate Authorities

Reliance on certificate authorities for the establishment of secure sessions includes the use of Transport Layer Security (TLS) certificates. These certificates, after verification by their respective certificate authorities, facilitate the establishment of protected sessions between web clients and web servers.

SC-28(1)enhancement

Cryptographic Protection

The selection of cryptographic mechanisms is based on the need to protect the confidentiality and integrity of organizational information. The strength of mechanism is commensurate with the security category or classification of the information. Organizations have the flexibility to encrypt information on system components or media or encrypt data structures

SC-28(2)enhancement

Offline Storage

Removing organizational information from online storage to offline storage eliminates the possibility of individuals gaining unauthorized access to the information through a network. Therefore, organizations may choose to move information to offline storage in lieu of protecting such information in online storage.

SC-28(3)enhancement

Cryptographic Keys

A Trusted Platform Module (TPM) is an example of a hardware-protected data store that can be used to protect cryptographic keys.

SC-29(1)enhancement

Virtualization Techniques

While frequent changes to operating systems and applications can pose significant configuration management challenges, the changes can result in an increased work factor for adversaries to conduct successful attacks. Changing virtual operating systems or applications, as opposed to changing actual operating systems or applications, provides virtual changes t

SC-30(2)enhancement

Randomness

Randomness introduces increased levels of uncertainty for adversaries regarding the actions that organizations take to defend their systems against attacks. Such actions may impede the ability of adversaries to correctly target information resources of organizations that support critical missions or business functions. Uncertainty may also cause adversaries

SC-30(3)enhancement

Change Processing and Storage Locations

Adversaries target critical mission and business functions and the systems that support those mission and business functions while also trying to minimize the exposure of their existence and tradecraft. The static, homogeneous, and deterministic nature of organizational systems targeted by adversaries make such systems more susceptible to attacks with less a

SC-30(4)enhancement

Misleading Information

Employing misleading information is intended to confuse potential adversaries regarding the nature and extent of controls deployed by organizations. Thus, adversaries may employ incorrect and ineffective attack techniques. One technique for misleading adversaries is for organizations to place misleading information regarding the specific controls deployed in

SC-30(5)enhancement

Concealment of System Components

By hiding, disguising, or concealing critical system components, organizations may be able to decrease the probability that adversaries target and successfully compromise those assets. Potential means to hide, disguise, or conceal system components include the configuration of routers or the use of encryption or virtualization techniques.

SC-31(2)enhancement

Maximum Bandwidth

The complete elimination of covert channels, especially covert timing channels, is usually not possible without significant performance impacts.

SC-31(3)enhancement

Measure Bandwidth in Operational Environments

Measuring covert channel bandwidth in specified operational environments helps organizations determine how much information can be covertly leaked before such leakage adversely affects mission or business functions. Covert channel bandwidth may be significantly different when measured in settings that are independent of the specific environments of operation

SC-34(1)enhancement

No Writable Storage

Disallowing writeable storage eliminates the possibility of malicious code insertion via persistent, writeable storage within the designated system components. The restriction applies to fixed and removable storage, with the latter being addressed either directly or as specific restrictions imposed through access controls for mobile devices.

SC-34(2)enhancement

Integrity Protection on Read-only Media

Controls prevent the substitution of media into systems or the reprogramming of programmable read-only media prior to installation into the systems. Integrity protection controls include a combination of prevention, detection, and response.

SC-36(1)enhancement

Polling Techniques

Distributed processing and/or storage may be used to reduce opportunities for adversaries to compromise the confidentiality, integrity, or availability of organizational information and systems. However, the distribution of processing and storage components does not prevent adversaries from compromising one or more of the components. Polling compares the pro

SC-36(2)enhancement

Synchronization

[SC-36](#sc-36) and [CP-9(6)](#cp-9.6) require the duplication of systems or system components in distributed locations. The synchronization of duplicated and redundant services and data helps to ensure that information contained in the distributed locations can be used in the mission or business functions of organizations, as needed.

SC-37(1)enhancement

Ensure Delivery and Transmission

Techniques employed by organizations to ensure that only designated systems or individuals receive certain information, system components, or devices include sending authenticators via an approved courier service but requiring recipients to show some form of government-issued photographic identification as a condition of receipt.

SC-39(1)enhancement

Hardware Separation

Hardware-based separation of system processes is generally less susceptible to compromise than software-based separation, thus providing greater assurance that the separation will be enforced. Hardware separation mechanisms include hardware memory management.

SC-40(1)enhancement

Electromagnetic Interference

The implementation of cryptographic mechanisms for electromagnetic interference protects systems against intentional jamming that might deny or impair communications by ensuring that wireless spread spectrum waveforms used to provide anti-jam protection are not predictable by unauthorized individuals. The implementation of cryptographic mechanisms may also c

SC-40(2)enhancement

Reduce Detection Potential

The implementation of cryptographic mechanisms to reduce detection potential is used for covert communications and to protect wireless transmitters from geo-location. It also ensures that the spread spectrum waveforms used to achieve a low probability of detection are not predictable by unauthorized individuals. Mission requirements, projected threats, conce

SC-40(3)enhancement

Imitative or Manipulative Communications Deception

The implementation of cryptographic mechanisms to identify and reject imitative or manipulative communications ensures that the signal parameters of wireless transmissions are not predictable by unauthorized individuals. Such unpredictability reduces the probability of imitative or manipulative communications deception based on signal parameters alone.

SC-40(4)enhancement

Signal Parameter Identification

The implementation of cryptographic mechanisms to prevent the identification of wireless transmitters protects against the unique identification of wireless transmitters for the purposes of intelligence exploitation by ensuring that anti-fingerprinting alterations to signal parameters are not predictable by unauthorized individuals. It also provides anonymit

SC-42(2)enhancement

Authorized Use

Information collected by sensors for a specific authorized purpose could be misused for some unauthorized purpose. For example, GPS sensors that are used to support traffic navigation could be misused to track the movements of individuals. Measures to mitigate such activities include additional training to help ensure that authorized individuals do not abuse

SC-42(4)enhancement

Notice of Collection

Awareness that organizational sensors are collecting data enables individuals to more effectively engage in managing their privacy. Measures can include conventional written notices and sensor configurations that make individuals directly or indirectly aware through other devices that the sensor is collecting information. The usability and efficacy of the no

SC-42(5)enhancement

Collection Minimization

Although policies to control for authorized use can be applied to information once it is collected, minimizing the collection of information that is not needed mitigates privacy risk at the system entry point and mitigates the risk of policy control failures. Sensor configurations include the obscuring of human features, such as blurring or pixelating flesh

SC-7(10)enhancement

Prevent Exfiltration

Prevention of exfiltration applies to both the intentional and unintentional exfiltration of information. Techniques used to prevent the exfiltration of information from systems may be implemented at internal endpoints, external boundaries, and across managed interfaces and include adherence to protocol formats, monitoring for beaconing activity from systems

SC-7(11)enhancement

Restrict Incoming Communications Traffic

General source address validation techniques are applied to restrict the use of illegal and unallocated source addresses as well as source addresses that should only be used within the system. The restriction of incoming communications traffic provides determinations that source and destination address pairs represent authorized or allowed communications. De

SC-7(12)enhancement

Host-based Protection

Host-based boundary protection mechanisms include host-based firewalls. System components that employ host-based boundary protection mechanisms include servers, workstations, notebook computers, and mobile devices.

SC-7(14)enhancement

Protect Against Unauthorized Physical Connections

Systems that operate at different security categories or classification levels may share common physical and environmental controls, since the systems may share space within the same facilities. In practice, it is possible that these separate systems may share common equipment rooms, wiring closets, and cable distribution paths. Protection against unauthoriz

SC-7(15)enhancement

Networked Privileged Accesses

Privileged access provides greater accessibility to system functions, including security functions. Adversaries attempt to gain privileged access to systems through remote access to cause adverse mission or business impacts, such as by exfiltrating information or bringing down a critical system capability. Routing networked, privileged access requests throug

SC-7(16)enhancement

Prevent Discovery of System Components

Preventing the discovery of system components representing a managed interface helps protect network addresses of those components from discovery through common tools and techniques used to identify devices on networks. Network addresses are not available for discovery and require prior knowledge for access. Preventing the discovery of components and devices

SC-7(17)enhancement

Automated Enforcement of Protocol Formats

System components that enforce protocol formats include deep packet inspection firewalls and XML gateways. The components verify adherence to protocol formats and specifications at the application layer and identify vulnerabilities that cannot be detected by devices operating at the network or transport layers.

SC-7(18)enhancement

Fail Secure

Fail secure is a condition achieved by employing mechanisms to ensure that in the event of operational failures of boundary protection devices at managed interfaces, systems do not enter into unsecure states where intended security properties no longer hold. Managed interfaces include routers, firewalls, and application gateways that reside on protected subn

SC-7(19)enhancement

Block Communication from Non-organizationally Configured Hosts

Communication clients independently configured by end users and external service providers include instant messaging clients and video conferencing software and applications. Traffic blocking does not apply to communication clients that are configured by organizations to perform authorized functions.

SC-7(20)enhancement

Dynamic Isolation and Segregation

The capability to dynamically isolate certain internal system components is useful when it is necessary to partition or separate system components of questionable origin from components that possess greater trustworthiness. Component isolation reduces the attack surface of organizational systems. Isolating selected system components can also limit the damage

SC-7(21)enhancement

Isolation of System Components

Organizations can isolate system components that perform different mission or business functions. Such isolation limits unauthorized information flows among system components and provides the opportunity to deploy greater levels of protection for selected system components. Isolating system components with boundary protection mechanisms provides the capabili

SC-7(24)enhancement

Personally Identifiable Information

Managing the processing of personally identifiable information is an important aspect of protecting an individual’s privacy. Applying, monitoring for, and documenting exceptions to processing rules ensure that personally identifiable information is processed only in accordance with established privacy requirements.

SC-7(25)enhancement

Unclassified National Security System Connections

A direct connection is a dedicated physical or virtual connection between two or more systems. Organizations typically do not have complete control over external networks, including the Internet. Boundary protection devices (e.g., firewalls, gateways, and routers) mediate communications and information flows between unclassified national security systems and

SC-7(26)enhancement

Classified National Security System Connections

A direct connection is a dedicated physical or virtual connection between two or more systems. Organizations typically do not have complete control over external networks, including the Internet. Boundary protection devices (e.g., firewalls, gateways, and routers) mediate communications and information flows between classified national security systems and e

SC-7(27)enhancement

Unclassified Non-national Security System Connections

A direct connection is a dedicated physical or virtual connection between two or more systems. Organizations typically do not have complete control over external networks, including the Internet. Boundary protection devices (e.g., firewalls, gateways, and routers) mediate communications and information flows between unclassified non-national security systems

SC-7(28)enhancement

Connections to Public Networks

A direct connection is a dedicated physical or virtual connection between two or more systems. A public network is a network accessible to the public, including the Internet and organizational extranets with public access.

SC-7(29)enhancement

Separate Subnets to Isolate Functions

Separating critical system components and functions from other noncritical system components and functions through separate subnetworks may be necessary to reduce susceptibility to a catastrophic or debilitating breach or compromise that results in system failure. For example, physically separating the command and control function from the in-flight entertai

Planned Academy connection

Bare Metal Cyber course coverage for this family.

These titles come from the approved NIST SP 800-53 course plan. They are shown as planned coverage and do not claim a public lesson URL before publication.

  1. Episode 41: System and Communications Protection — Part One: Segmentation and boundary thinking
  2. Episode 42: System and Communications Protection — Part Two: Cryptography and session protections
  3. Episode 43: System and Communications Protection — Part Three: Evidence, coverage, and pitfalls
  4. Episode 44: System and Communications Protection — Part Four: Advanced topics and metrics