Information in Shared System Resources
LOW ✓ MODERATE ✓ HIGHRequirements NIST SOURCE
Prevent unauthorized and unintended information transfer via shared system resources.
Discussion (NIST Supplemental Guidance)
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 shared system resources after those resources have been released back to the system. Information in shared system resources also applies to encrypted representations of information. In other contexts, control of information in shared system resources is referred to as object reuse and residual information protection. Information in shared system resources does not address information remanence, which refers to the residual representation of data that has been nominally deleted; covert channels (including storage and timing channels), where shared system resources are manipulated to violate information flow restrictions; or components within systems for which there are only single users or roles.
Enhancements NIST SOURCE
SC-4(1) Security Levels WITHDRAWN
Withdrawn. Incorporated into SC-4.
SC-4(2) Multilevel or Periods Processing LOW MODERATE HIGH
Prevent unauthorized information transfer via shared resources in accordance with [procedures] when system processing explicitly switches between different information classification levels or security categories.
Discussion
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 information.
Implementation Guidance
Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.
No engineering interpretation has been authored for SC-4 yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.
Assessment
Assessment Objectives
- unauthorized information transfer via shared system resources is prevented;
- unintended information transfer via shared system resources is prevented.
Examine
[SELECT FROM: System and communications protection policy; procedures addressing information protection in shared system resources; system design documentation; system configuration settings and associated documentation; system audit records; system security plan; other relevant documents or records].
Interview
[SELECT FROM: System/network administrators; organizational personnel with information security responsibilities; system developer].
Test
[SELECT FROM: Mechanisms preventing the unauthorized and unintended transfer of information via shared system resources].
Overlays
STIGs & CCIs
No STIG checks or CCI mappings are currently loaded for SC-4. This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.
Learn more about STIG/CCI integration →Evidence
Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.
Policy
- System and communications protection policy
- system security plan
Configuration
- system design documentation
- system configuration settings and associated documentation
Testing
- Mechanisms preventing the unauthorized and unintended transfer of information via shared system resources
Other Records
- procedures addressing information protection in shared system resources
- system audit records
- other relevant documents or records