Trusted Path
LOW MODERATE HIGHRequirements NIST SOURCE
Requirement Context
This element is part of SC-11 — Trusted Path. See the Assessment section below for the related SP 800-53A examine/interview/test procedures. No engineering interpretation has been authored for this control yet.
Requirement Context
This element is part of SC-11 — Trusted Path. See the Assessment section below for the related SP 800-53A examine/interview/test procedures. No engineering interpretation has been authored for this control yet.
Discussion (NIST Supplemental Guidance)
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 are protected from modification by and disclosure to untrusted applications. Organizations employ trusted paths for trustworthy, high-assurance connections between security functions of systems and users, including during system logons. The original implementations of trusted paths employed an out-of-band signal to initiate the path, such as using the <BREAK> key, which does not transmit characters that can be spoofed. In later implementations, a key combination that could not be hijacked was used (e.g., the <CTRL> + <ALT> + <DEL> keys). Such key combinations, however, are platform-specific and may not provide a trusted path implementation in every case. The enforcement of trusted communications paths is provided by a specific implementation that meets the reference monitor concept.
Enhancements NIST SOURCE
SC-11(1) Irrefutable Communications Path LOW MODERATE HIGH
- (a) Provide a trusted communications path that is irrefutably distinguishable from other communications paths; and
- (b) Initiate the trusted communications path for communications between the [security functions] of the system and the user.
Discussion
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 cannot be spoofed.
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-11 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
- one of the following PARAMETER VALUES is selected: {physically; logically};
- security functions of the system are defined;
- a <SC-11_ODP[01] SELECTED PARAMETER VALUE> isolated trusted communication path is provided for communications between the user and the trusted components of the system;
- users are permitted to invoke the trusted communication path for communications between the user and the <SC-11_ODP[02] security functions> of the system, including authentication and re-authentication, at a minimum.
Examine
[SELECT FROM: System and communications protection policy; procedures addressing trusted communication paths; security plan; system design documentation; system configuration settings and associated documentation; assessment results from independent, testing organizations; 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 supporting and/or implementing trusted communication paths].
STIGs & CCIs
No STIG checks or CCI mappings are currently loaded for SC-11. 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
- security plan
- system security plan
Configuration
- system design documentation
- system configuration settings and associated documentation
Testing
- Mechanisms supporting and/or implementing trusted communication paths
Other Records
- procedures addressing trusted communication paths
- assessment results from independent, testing organizations
- system audit records
- other relevant documents or records