LLMPrompt AC.L2-3.1.3

I am a cybersecurity manager working for an organization that is a DoD contractor. I need to implement various security practices that conform to DoD's CMMC program at level 2. The CMMC program stipulates security practices that are based on NIST Special Publication 800-171 R2. For each security practice of CMMC Level 2, I need to show evidence that my organization is in compliance with CMMC. Each security practice has a security requirement and several assessment objectives that support that high-level security requirement.

I am assessing one of the assessment objectives within the practice AC.L2-3.1.3 "CONTROL CUI FLOW." The CMMC program has published the following assessment guidance, so take them into account as you formulate your response. Also refer to the attached CMMC Level 2 Assessment Guide for more context and information about the practice.

A. SECURITY REQUIREMENT: Control the flow of CUI in accordance with approved authorizations.

B. ASSESSMENT OBJECTIVES [NIST SP 800-171A]: Determine if: [a] information flow control policies are defined; [b] methods and enforcement mechanisms for controlling the flow of CUI are defined; [c] designated sources and destinations (e.g., networks, individuals, and devices) for CUI within the system and between interconnected systems are identified; [d] authorizations for controlling the flow of CUI are defined; and [e] approved authorizations for controlling the flow of CUI are enforced.

C. ASSESSMENT APPROACH AND OBJECTS: I have three assessment approaches for assessing any security practice. They are listed as follows:

C1. Examine: The process of checking, inspecting, reviewing, observing, studying, or analyzing one or more assessment objectives to facilitate understanding, achieve clarification, or obtain evidence. The results are used to support the determination of security safeguard existence, functionality, correctness, completeness, and potential for improvement over time.

C2. Interview: The process of conducting discussion with individuals or groups of individuals in an organization to facilitate understanding, achieve clarification, or lead to the location of evidence. The results are used to support the determination of security safeguard existence, functionality, correctness, completeness, and potential for improvement over time.

C3. Test: The process of exercising one or more assessment objects under specified conditions to compare actual with expected behavior. The results are used to support the determination of security safeguard existence, functionality, correctness, completeness, and potential for improvement over time.

D. ASSESSMENT OBJECTS: Each assessment approach can yield potential assessment objects:

D1. Examine: [SELECT FROM: Access control policy; information flow control policies; procedures addressing information flow enforcement; system security plan; system design documentation; system configuration settings and associated documentation; list of information flow authorizations; system baseline configuration; system audit logs and records; other relevant documents or records].

D2. Interview: [SELECT FROM: System or network administrators; personnel with information security responsibilities; system developers].

D3. Test: [SELECT FROM: Mechanisms implementing information flow enforcement policy].

The previously mentioned assessment objects should help to support the recommended evidence.

E. DISCUSSION: Organizations may choose to define access privileges or other attributes by account, by type of account, or a combination of both. System account types include individual, shared, group, system, anonymous, guest, emergency, developer, manufacturer, vendor, and temporary. Other attributes required for authorizing access include restrictions on time-of-day, day-of- week, and point-of-origin. In defining other account attributes, organizations consider system-related requirements (e.g., system upgrades scheduled maintenance,) and mission or business requirements, (e.g., time zone differences, customer requirements, remote access to support travel requirements).

F. FURTHER DISCUSSION: Information flow control regulates where information can travel within a system and between systems (versus who can access the information) and without explicit regard to subsequent accesses to that information. Flow control restrictions include the following: 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 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.

Organizations commonly use 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 systems and between interconnected systems. Flow control is based on characteristics of the information or the information path. Enforcement occurs in boundary protection devices (e.g., gateways, routers, guards, encrypted tunnels, firewalls) that employ rule sets or establish configuration settings that restrict 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 and inspection mechanisms (i.e., hardware, firmware, and software components) that are critical to information flow enforcement.

Transferring information between systems representing different security domains with different security policies introduces risk that such transfers violate one or more domain security policies.

Organizations consider the shared nature of commercial telecommunications services in the implementation of security requirements associated with the use of such services. Commercial telecommunications services are commonly based on network components and consolidated management systems shared by all attached commercial customers and may also include third party-provided access lines and other service elements. Such transmission services may represent sources of increased risk despite contract security provisions. NIST SP 800-41 provides guidance on firewalls and firewall policy. SP 800-125B provides guidance on security for virtualization technologies.

In such situations, information owners or 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: prohibiting information transfers between interconnected systems (i.e., allowing access only); employing hardware mechanisms to enforce one-way information flows; and implementing trustworthy regrading mechanisms to reassign security attributes and security labels.

G. Examples:

G1. Example 1: As a system administrator, you configure a proxy device on your company’s network. Your goal is to better mask and protect the devices inside the network while enforcing information flow policies. After the device is configured, information does not flow directly from the internal network to the internet. The proxy device intercepts the traffic and analyzes it to determine if the traffic conforms to organization information flow control policies. If it does, the device allows the information to pass to its destination [b]. The proxy blocks traffic that does not meet policy requirements [e].

G2. Example 2: As a subcontractor on a DoD contract, your organization sometimes needs to transmit CUI to the prime contractor. You create a policy document that specifies who is allowed to transmit CUI and that such transmission requires manager approval [a,c,d]. The policy instructs users to encrypt any CUI transmitted via email or to use a designated secure file sharing utility [b,d]. The policy states that users who do not follow appropriate procedures may be subject to disciplinary action [e].

H. Potential Assessment Considerations: Are designated sources of regulated data identified within the system (e.g., internal network and IP address) and between interconnected systems (e.g., external networks, IP addresses, ports, and protocols) [c]? Are designated destinations of regulated data identified within the system (e.g., internal network and IP address) and between interconnected systems (external networks and IP addresses) [c]? Are authorizations defined for each source and destination within the system and between interconnected systems (e.g., allow or deny rules for each combination of source and destination) [d]? Are approved authorizations for controlling the flow of regulated data enforced within the system and between interconnected systems (e.g., traffic between authorized sources and destinations is allowed and traffic between unauthorized sources and destinations is denied) [e]?

I. EVIDENCE TYPES: Finally, I have four evidence types that I can collect. The definitions of the evidence types are as follows:

I1. Artifacts: Tangible and reviewable records that are the direct outcome of a practice or process being performed by a system, person, or persons performing a role in that practice, control, or process. (See CAP Glossary for additional details.)

I2. Document: Any tangible thing which constitutes or contains information and means the original and any copies (whether different from the originals because of notes made on such copies or otherwise) of all writing of every kind and description over which an agency has authority. (See CAP Glossary for additional details.)

I3. Physical Review: An on-premise observation of Evidence.

I4. Screen Share: Live observation ""over the shoulder"" of a user as they share their computer screen while performing a task.

J. KEY REFERENCES: NIST SP 800-171 Rev 2 3.1.3