SC-27: Platform-independent Applications

To meet the sc-27: platform-independent applications requirement, you must define which platform-independent applications your system is required to include, ensure they are implemented across the system boundary where applicable, and maintain assessor-ready evidence that the applications are present, approved, and operated as intended ¹.

Key takeaways:

• SC-27 is an explicit “include these applications” control; it fails if you cannot name the required apps and show they exist in the system ¹.
• Operationalize it by scoping the system boundary, listing the required platform-independent apps, and tying them to build/config, inventory, and change control artifacts ¹.
• Most audit pain comes from undefined parameters (the “ODP” list), unclear ownership, and missing recurring evidence that the apps remain present after changes ¹.

SC-27 is easy to misread as a “good engineering idea” instead of what it is: a requirement to include specific platform-independent applications in your organizational system(s) ¹. The control text contains an organization-defined parameter (ODP), which means you do not pass by saying “we use containers” or “our code is portable.” You pass by documenting the specific platform-independent applications you are required to include, implementing them within the system boundary, and proving they are present and governed through normal operations ¹.

For a CCO, GRC lead, or compliance officer supporting a federal system or a contractor system handling federal data, SC-27 is primarily an assessment-readiness control: can you show an assessor (or customer) a crisp list of required platform-independent applications, where they run, who owns them, and what evidence demonstrates they are implemented and maintained ¹? This page gives you requirement-level implementation guidance you can hand to control owners and auditors without translating theory into action.

Regulatory text

Control requirement (verbatim): “Include within organizational systems the following platform independent applications: {{ insert: param, sc-27_odp }}.” ¹

What the operator must do:

1. Fill in the blank: define the organization-defined parameter (the list of “platform independent applications” required for your environment) and get it approved as a control parameter ¹.
2. Include them within the system: ensure those applications are actually implemented within the assessed system boundary (not just “available somewhere in IT”) ¹.
3. Prove it continuously: retain evidence that the required applications are deployed, inventoried, and governed through change control so the control stays true after upgrades and replatforming ¹.

Plain-English interpretation

SC-27 requires you to standardize on a set of applications that can run across multiple platforms (for example, across OSes, hosting environments, or hardware architectures), then ensure your systems actually include them ¹. In practice, this is usually about avoiding hard dependencies on a single platform that becomes a security, availability, or supply-chain constraint.

What assessors look for is straightforward:

• A defined list of required platform-independent applications (the SC-27 ODP list).
• Clear mapping to system components and environments where those apps are present.
• Evidence that the list is enforced through normal engineering controls (inventory, build standards, change control).

Who it applies to (entity and operational context)

Entity types commonly in scope: federal information systems and contractor systems handling federal data ¹.

Operational contexts where SC-27 becomes “real”:

• Systems with multiple operating environments (dev/test/prod; on-prem plus cloud; multiple cloud providers).
• Mission/business services that must survive platform changes (OS upgrades, cloud migration, hardware refresh).
• Programs where the customer or authorizing official expects NIST SP 800-53 alignment and will test evidence, not intent ².

Typical control owners: enterprise architecture, platform engineering, application security, or the system owner. GRC owns the requirement statement, parameter definition workflow, and evidence pack assembly.

What you actually need to do (step-by-step)

Step 1: Define the SC-27 parameter (your required app list)

SC-27 includes an ODP placeholder; you must define it ¹. Build a short “SC-27 Parameter Sheet” with:

• System boundary: which system(s) this list applies to.
• Required platform-independent applications: explicit names and versions or version ranges.
• Business/technical rationale: why these are required in the system.
• Approval: control owner + authorizing party sign-off.

Practical tip: keep the initial list small and defensible. Assessors prefer a clear, enforceable list over a sprawling catalog nobody can prove exists everywhere.

Step 2: Map required applications to where they run

Create a mapping that answers: “Where, exactly, are these apps included within the system?” ¹

• For each required application, list:
  • Hosting patterns (VM images, containers, managed service, endpoint install package).
  • Environments (prod, staging, DR).
  • Primary owner/team.
  • Source of truth (CMDB, asset inventory, Git repo, image registry entry).

Deliverable: a one-page table your assessor can read in five minutes.

Step 3: Build the control into engineering guardrails

SC-27 fails in real life when teams can “accidentally” stop including the required apps after a platform change. Add guardrails that create durable evidence trails:

• Golden images / base container images that include the required application components where appropriate.
• CI/CD checks that validate required runtime components are present (for apps packaged into artifacts).
• Configuration management that enforces install/config state (where the model is “must be installed and configured”).
• Change control hooks: any proposed platform migration must include an SC-27 impact check (“Will the required platform-independent apps remain included?”).

Keep the guardrails proportional. You want repeatable proof, not bureaucracy.

Step 4: Tie SC-27 to inventory and change management evidence

Decide how you will prove “included within organizational systems” on demand:

• Inventory evidence: reports showing the application is deployed across relevant assets.
• Build evidence: versioned base images or manifests showing inclusion.
• Change evidence: tickets/PRs showing changes were reviewed for SC-27 impact and approved.

Daydream (or any GRC system) fits best here as the control record that links: owner, parameter definition, mapping table, and recurring evidence tasks, so your evidence stays current without hunting across tools during an assessment ¹.

Step 5: Operate it as an “always true” control

Set an operating rhythm that matches your change velocity:

• Trigger evidence refresh on platform changes, base image updates, OS upgrades, or hosting migrations.
• Review the SC-27 app list when introducing major new platforms or deprecating existing ones.
• Validate exceptions: if a required app cannot be included in a particular segment, document the rationale, scope the exception narrowly, and record compensating measures where applicable.

Required evidence and artifacts to retain

Maintain an assessor-ready SC-27 evidence packet with:

• SC-27 ODP parameter definition (the required application list) and approvals ¹.
• System boundary statement for where SC-27 is claimed.
• Application-to-environment mapping table (apps → components/environments/owners).
• Inventory extracts (CMDB, asset management, endpoint management, registry listings) showing presence.
• Build artifacts (base image manifests, SBOM entries if you have them, container image tags, package lists).
• Change records demonstrating ongoing governance (tickets, PRs, CAB notes).
• Exception register (if any), with scope, time bounds, and approval.

Common exam/audit questions and hangups

Expect assessors to ask:

• “What are your platform-independent applications for SC-27, and who approved this list?” ¹
• “Show me where each one is included in the system boundary.”
• “How do you know they are still included after your last platform or pipeline change?”
• “Which tool is your source of truth for deployment evidence?”
• “Do you have any segments where the requirement is not met? Show exceptions and approvals.”

Hangups that stall assessments:

• The ODP list is missing or vague (“standard tools”).
• The team provides architectural intent, not objective deployment evidence.
• Evidence exists, but cannot be tied cleanly to the assessed system boundary.

Frequent implementation mistakes and how to avoid them

1. Leaving the SC-27 parameter undefined.
   Fix: treat the ODP list like a formal control parameter with owner, approval, and change tracking ¹.

2. Confusing “portable code” with “platform-independent applications.”
   Fix: name the actual applications/components you are claiming are included and prove they are present in the system.

3. Relying on tribal knowledge.
   Fix: make the mapping table and inventory extracts the canonical proof set.

4. Proving once, then drifting.
   Fix: attach SC-27 checks to platform change workflows and create recurring evidence pulls tied to system releases.

5. Over-scoping the list.
   Fix: keep the required list limited to what you can enforce and evidence across the system boundary.

Enforcement context and risk implications

No public enforcement cases were provided for SC-27 in the source material. Practically, the risk is assessment failure, loss of authorization/attestation confidence, and increased operational fragility when platforms change. Treat SC-27 as a control that reduces platform lock-in and improves survivability during migrations, but document it like an auditor will test it: explicit list, explicit inclusion, durable evidence ¹.

A practical 30/60/90-day execution plan

First 30 days (define and assign)

• Assign a control owner and a technical owner for SC-27 evidence.
• Draft the SC-27 ODP list and get formal approval ¹.
• Identify sources of truth for “included” evidence (CMDB, endpoint manager, image registry, CI/CD).

Days 31–60 (implement guardrails and mapping)

• Build the application-to-environment mapping table.
• Add CI/CD or image-standard checks where feasible.
• Create an SC-27 evidence checklist and store the first complete evidence packet.

Days 61–90 (operationalize and test)

• Run a tabletop assessment: have someone unfamiliar with the system try to validate SC-27 using only the evidence packet.
• Wire SC-27 checks into platform migration/change control.
• Set recurring evidence refresh tasks in Daydream so evidence stays current across releases ¹.

Frequently Asked Questions

What counts as a “platform-independent application” for SC-27?

SC-27 requires you to specify the platform-independent applications via the organization-defined parameter, then include them in the system ¹. Define this list in a way your engineers can implement and your assessor can verify.

Do we have to include the same applications in every environment (dev/test/prod)?

The control text says “include within organizational systems,” so scope hinges on your system boundary and how you define inclusion in that boundary ¹. If dev/test are in scope for your assessment, be ready to show inclusion or approved exceptions.

Can we meet SC-27 with SaaS applications?

Potentially, if you can show the required platform-independent application is included within the assessed system boundary and you can evidence its presence and governance ¹. Many teams still need internal artifacts like configuration baselines and inventory records to make that claim defensible.

What evidence is strongest for auditors?

Objective, system-generated evidence wins: inventory extracts, image manifests, package lists, and change records tied to the system boundary ¹. Screenshots without provenance usually create follow-up requests.

How do we handle exceptions where a required app can’t run on a target platform?

Document the exception with scope, rationale, and approval, and keep it tied to the system boundary and change control record ¹. Avoid open-ended exceptions that never expire.

How should a GRC team operationalize SC-27 without becoming a bottleneck?

Keep GRC focused on the parameter definition, ownership, and evidence workflow, and let engineering own implementation details and system-generated proof ¹. Daydream helps by linking the control to owners, procedures, and recurring artifacts so assessments do not turn into manual evidence hunts ¹.

Footnotes

1. NIST SP 800-53 Rev. 5 OSCAL JSON

2. NIST SP 800-53 Rev. 5