03.13.04: Shared Resource Control

Beyond CMMC Level 1

The free web app covers the 17 CMMC Level 1 practices. This requirement is part of the full NIST 800-171 set — get the desktop app to work on all 110 requirements with SPRS scoring. Previously saved data is shown read-only below, and your data always remains exportable in full.

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Security Requirements for 03.13.04 Shared Resource Control

The control of information in shared system resources (e.g., registers, cache memory, main memory, hard disks) is also commonly referred to as object reuse and residual information protection. This requirement prevents 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 any current users or roles (or current processes acting on behalf of current users or roles) that obtain access to shared system resources after those resources have been released back to the system. This requirement also applies to encrypted representations of information. This requirement does not address information remanence, which refers to residual representation of data that has been nominally deleted; covert channels (including storage or timing channels) where shared resources are manipulated to violate information flow restrictions; or components within systems for which there are only single users or roles.

Assessment GuidanceExamine 0/7

How an assessor determines this requirement is met. Source: CMMC Assessment Guide – Level 2, Version 2.13 (NIST SP 800-171 Rev. 2).

Discussion

No shared system resource, such as cache memory, hard disks, registers, or main memory may pass information from one user to another user. In other words, when objects are reused no residual information should exist on that object. This protects the confidentiality of the information. This is typically a feature provided by operating system and software vendors.

Examples

Example 1
You are a system administrator responsible for creating and deploying the system hardening procedures for your company’s computers. You ensure that the computer baselines include software patches to prevent attackers from exploiting flaws in the processor architecture to read data (e.g., the Meltdown and Spectre exploits). You also verify that the computer operating system is configured to prevent users from accessing other users’ folders [a].

Assessment Methods

Examine

The process of reviewing, inspecting, observing, studying, or analyzing assessment objects (e.g., policies, procedures, plans, system designs, mechanisms) to facilitate understanding, achieve clarification, or obtain evidence.Example: An assessor reads the access control policy and inspects system configuration settings to confirm they match.

Not all of the evidence listed is required to meet this requirement — check the items your organization has collected.

System and communications protection policy
Procedures addressing application partitioning
System security plan
System design documentation
System configuration settings and associated documentation
System audit logs and records
Other relevant documents or records

Interview

The process of holding discussions with individuals or groups within an organization to facilitate understanding, achieve clarification, or identify the location of evidence.Example: An assessor asks a system administrator to describe how user accounts are approved, reviewed, and disabled.

System or network administrators
Personnel with information security responsibilities
System developer

Test

The process of exercising assessment objects (e.g., activities, mechanisms) under specified conditions to compare actual behavior with expected behavior.Example: An assessor attempts to sign in with a disabled account to confirm that access is denied.

Separation of user functionality from system management functionality

Potential Assessment Considerations

Are shared system resources identified and documented [a]?

Key References

NIST SP 800-171 Rev. 2 3.13.4

Overview