Security requirement
- a.Determine alternate work sites allowed for use by employees.
- b.Employ the following security requirements at alternate work sites: [Organization-defined: security requirements].
Discussion
Alternate work sites include the private residences of employees or other facilities designated by the organization. Alternate work sites can provide readily available alternate locations during contingency operations. Organizations can define different security requirements for specific alternate work sites or types of sites, depending on the work-related activities conducted at the sites. Assessing the effectiveness of the requirements and providing a means to communicate incidents at alternate work sites supports the contingency planning activities of organizations.
Tailoring decisions required
Resolve these values through the governing organization’s approved tailoring and risk-management process before declaring the requirement implemented.
Implementation perspective
Treat Alternate Work Site as a CUI protection outcome that must be reflected in the system boundary, documented implementation, operational behavior, and assessment evidence. Pay particular attention to physical access, facility protection, visitor accountability, and protection of system components that handle CUI.
- Confirm the requirement is in scope for the CUI system components, services, users, and external connections being assessed.
- Resolve every organization-defined parameter through an approved governance and tailoring process.
- Map each clause of the requirement to an accountable owner, implementation mechanism, and evidence source.
- Verify that inherited and shared implementations are supported by current provider evidence and responsibility boundaries.
- Collect evidence during normal operation and review changes, exceptions, and deficiencies on a risk-based cadence.
Questions to ask
- Which CUI assets, data flows, users, and services are protected by this requirement?
- Which portions are implemented locally, inherited, shared, or not applicable, and what evidence supports that determination?
- Do the system security plan, deployed configuration, operating process, and assessment evidence tell the same story?
- What change, incident, or threshold should trigger reassessment?
Evidence and validation
- badge and visitor logs
- physical access reviews
- facility diagrams and sensor records
- environmental and power test results
Common failure patterns
- logical controls undermined by physical access
- tailgating or visitor exceptions normalized
- critical infrastructure omitted from access reviews
- environmental alarms disconnected from response
Assessment objectives and methods
Assessment objectives (2)
- a.
alternate work sites allowed for use by employees are determined.
- b.
the following security requirements are employed at alternate work sites: [Organization-defined: security requirements].
Examine
- physical protection policy and procedures
- procedures for alternate work sites for personnel
- list of security requirements for alternate work sites
- assessments of security requirements at alternate work sites
- system security plan
- other relevant documents or records
Interview
- personnel approving the use of alternate work sites
- personnel using alternate work sites
- personnel assessing security requirements at alternate work sites
- personnel with information security responsibilities
Test
- processes for security at alternate work sites
- mechanisms for supporting alternate work sites
- security requirements employed at alternate work sites
- means of communication between personnel at alternate work sites and security personnel
Source NIST SP 800-53 controls
These controls are referenced by the official SP 800-171 Rev. 3 OSCAL record. Open the corresponding control pages for complete control text, enhancements, D3FEND mappings, and related learning.
Authoritative sources
- NIST SP 800-171 Revision 3 official publication ↗
- NIST SP 800-171A Revision 3 official publication ↗
- NIST OSCAL Content release used for this import ↗
Bare Metal Cyber is an independent educational publisher and is not affiliated with or endorsed by NIST. The official publications, the responsible federal agency, and the governing contract or agreement determine applicability, tailoring, assessment depth, and required implementation.