NIST 800-171 Control 3.13.4: Shared Resource Control
Control 3.13.4 requires organizations to prevent unauthorized and unintended information transfer through shared system resources—a critical gap in environments where multiple users or processes access common storage, memory, or processing capacity. For SMBs managing sensitive data, this control ensures that residual data or covert channels don't expose confidential information to unauthorized parties.
What this means
Shared system resources—such as RAM, cache, temporary files, shared directories, and processor cores—can inadvertently carry sensitive data between users or applications. Without proper controls, one user or process could access leftover data from another, or exploit timing and resource allocation patterns to infer confidential information. This control requires technical and procedural measures to sanitize, isolate, or restrict access to these shared resources to prevent both intentional and accidental data leakage.
How to comply
- 1.Inventory all shared system resources across your infrastructure, including RAM, temporary storage, shared network drives, and processor caches.
- 2.Implement data sanitization procedures that securely overwrite shared memory and temporary storage when released by a user or process.
- 3.Configure logical separation or partitioning of shared resources to restrict cross-user visibility and access.
- 4.Enable process isolation and privilege restrictions to prevent applications from accessing memory or resources outside their allocated domains.
- 5.Deploy and configure shared resource management controls (e.g., container isolation, virtual machine segmentation) to enforce access boundaries.
- 6.Document resource-sharing architecture and controls in your system security plan, including sanitization procedures and validation methods.
- 7.Perform periodic testing or audits to verify that sanitization is effective and unauthorized information transfer is prevented.
- 8.Train system administrators and developers on secure shared resource handling and the risks of covert channels.
Evidence auditors look for
- System documentation detailing shared resource identification, isolation mechanisms, and sanitization procedures
- Configuration records showing memory protection, cache clearing, and temporary file deletion settings
- Access control policies and logs demonstrating logical separation of shared resources by user or process
- Test results or audit reports validating that residual data is not accessible across process or user boundaries
- Procedures and scripts that implement automatic sanitization of RAM, temporary storage, or shared directories
- Container or VM configuration files demonstrating resource isolation and namespace separation
- Security assessment or penetration test reports addressing covert channel risks and shared resource vulnerabilities
- Change management records for updates to resource-sharing controls or sanitization procedures
Frequently asked questions
When will FAQs be available?
The FAQ for this control is currently being prepared.
GRCWatch automatically maps your system configurations, memory management settings, and resource isolation policies to Control 3.13.4 requirements, generating evidence of sanitization procedures and flagging shared resource risks without manual audit overhead.
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