SA-5(5): Source Code

SA-5(5): Source Code requires you to put formal controls around source code received or produced under system acquisition, so you can verify integrity, manage changes, and maintain trustworthy provenance through the software lifecycle. Operationalize it by defining ownership, enforcing secure repositories and change control, and retaining audit-ready evidence that source code is protected and governed. ¹

Key takeaways:

• Treat source code as a controlled, high-value configuration item with defined custody, access control, and change management. ¹
• Make third-party source code contractually governable: receipt criteria, escrow/availability needs, and verification expectations. ²
• Evidence matters: you need repeatable artifacts that show code integrity, review, and controlled deployment. ¹

Compliance teams usually inherit SA controls after engineering has already picked tools and workflows. SA-5(5): Source Code is one of the SA enhancements that can fail audits for a simple reason: teams “do the right things” in practice, but cannot show consistent governance over code that enters, changes, and ships in regulated environments.

Treat this requirement as two problems you can solve quickly: (1) define which source code is in scope (internal, third-party, open source components brought in as code, code delivered under contract, infrastructure-as-code), and (2) prove you can control it end-to-end (where it lives, who can change it, how changes are reviewed, how releases are tied back to approved changes).

This page gives you requirement-level implementation guidance for a CCO, Compliance Officer, or GRC lead. You will get an operator’s interpretation, a step-by-step implementation checklist, the evidence to retain, the audit questions to expect, and a practical execution plan you can run with your engineering and procurement counterparts. ²

Regulatory text

Control: SA-5(5): Source Code.
Provided excerpt: “NIST SP 800-53 control SA-5.5.” ¹

What the operator must do (from an implementation standpoint): establish explicit governance over source code associated with system acquisition and development so that code is controlled, traceable, and protected against unauthorized change across its lifecycle. Your implementation should be documented, owned, and evidenced in a way an assessor can test. ²

Plain-English interpretation (what SA-5(5) is really asking)

SA-5(5): source code requirement expects that source code is not “just files in Git.” It is a managed asset with:

• Defined custody (who owns it, where it resides, and who administers the platform)
• Integrity protections (controls that prevent or detect tampering)
• Controlled change (review/approval paths and traceability from change to release)
• Acquisition discipline (how you accept source code from third parties and ensure you can maintain it, if required)

If you cannot prove where code came from, who changed it, and how changes were authorized, you have an integrity gap that can translate into production compromise risk and audit findings. ¹

Who it applies to (entity and operational context)

In-scope entities

• Federal information systems and programs implementing NIST SP 800-53 controls. ²
• Contractors and other third parties handling federal data or operating systems on behalf of the government where NIST SP 800-53 is contractually flowed down. ²

In-scope operational contexts

• Custom software development (internal teams or outsourced development).
• Procurement of software where source code is delivered (e.g., bespoke applications, regulated embedded software, critical tools).
• DevOps environments where infrastructure-as-code and deployment scripts materially affect production behavior.
• M&A or carve-outs where inherited repositories and commit history become part of the environment you must govern.

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

1) Name the control owner and define the boundary

1. Assign a primary owner (often AppSec, DevSecOps, or Engineering Enablement) and a GRC co-owner for evidence and testing coordination. ¹
2. Define “source code in scope” in one paragraph:
   • First-party application code
   • IaC (Terraform/CloudFormation), pipelines, deployment scripts
   • Third-party source code delivered under contract
   • Code snapshots received for build or audit purposes

Output: SA-5(5) control statement with scope, owner, and system applicability. ¹

2) Standardize where code lives (authoritative repositories)

1. Require all in-scope code to be stored in approved version control systems (VCS) under enterprise administration.
2. Prohibit “shadow repos” for production-bound code (personal accounts, unmanaged hosting).
3. Define repository-level baseline controls:
   • SSO enforcement
   • Role-based access
   • Audit logging enabled
   • Backup/retention configured

Output: “Approved repositories standard” and a register (even a simple inventory) of in-scope repos mapped to systems. ²

3) Enforce change control that is testable

Implement a minimum set of controls that create traceability:

1. Branch protection (or equivalent) for production branches.
2. Pull request (PR) reviews required before merge (define required reviewers and exceptions).
3. Segregation of duties expectations for high-risk systems (at least independent review for material changes).
4. Linkage between change request/ticket and PR (where applicable).

Operator tip: Auditors rarely care about your Git provider. They care that you can demonstrate a control that prevents unreviewed change from reaching the release branch and that exceptions are managed. ²

4) Establish integrity verification for received third-party code

If you receive source code from a third party (consultant, development shop, partner, contractor):

1. Define acceptance criteria: delivery format, complete repository history (if required), build instructions, and licensing attestations as relevant to your environment.
2. Require the third party to deliver code through controlled channels (enterprise repo transfer or controlled archive).
3. Validate integrity and provenance in a practical way:
   • Confirm code is received into an approved repo
   • Confirm commit authorship attribution is preserved when feasible
   • Record who accepted the delivery and when

Output: Third-party code intake checklist and completed intake records for each engagement. ²

5) Tie source code to builds and releases (release integrity story)

1. Require builds to be produced from the authoritative repo and a defined branch/tag.
2. Maintain a release record that ties:
   • Release identifier (tag/build)
   • Associated PRs/changes
   • Approvals (change ticket approvals, CAB approval if used)
3. Keep logs or system reports that demonstrate the pipeline executed from the expected source.

Output: Release evidence pack per major release or per sampling period (depending on audit scope). ²

6) Document the procedure and evidence cadence (make it sustainable)

Write a short operating procedure that states:

• Where code must be stored
• How access is granted and reviewed
• How changes are approved
• How third-party code is accepted
• What evidence is captured and how often

Daydream (or similar GRC tooling) becomes useful here because SA-5(5) often fails on “evidence sprawl.” The control is easier to maintain when evidence collection is mapped to owners and scheduled artifacts rather than ad hoc screenshots. ¹

Required evidence and artifacts to retain

Keep artifacts that an assessor can test without reading your entire SDLC handbook.

Core artifacts (typical minimum set)

• SA-5(5) control narrative: scope, owners, systems in scope, and implementation summary. ¹
• Source code repository inventory for in-scope systems (name, owner, platform, criticality). ²
• Repository configuration evidence (exported settings or admin screenshots) showing:
  • Branch protections
  • Review requirements
  • Audit logging enabled ²
• Access control evidence:
  • List of repo admins/maintainers
  • Access request/approval tickets (sample) ²
• Change evidence:
  • Sample PRs showing review/approval
  • Linkage to tickets (where used)
  • Exception approvals and expiration ²
• Third-party source code intake records (completed checklists, delivery confirmations, acceptance sign-off). ²
• Release traceability artifacts:
  • Release notes or deployment records tied to tags/commits
  • CI/CD run logs demonstrating source reference ²

Common exam/audit questions and hangups

What auditors ask

• “Show me where the production source code resides and who administers it.” ²
• “Demonstrate that changes to the main branch require review. Show settings, then show samples.” ¹
• “How do you accept source code from contractors, and how do you know it’s complete?” ²
• “What happens in an emergency change? Who can bypass controls, and how is it recorded?” ²
• “Prove that what you deployed maps back to approved code.” ²

Hangups that slow assessments

• Mixed tooling (some teams in GitHub, others in GitLab, some in on-prem) with inconsistent guardrails.
• “Temporary” admin access that never expires.
• Third-party code delivered as a zip file with no intake record and no traceability. ²

Frequent implementation mistakes and how to avoid them

1. Mistake: Treating open-source packages as “source code management” under SA-5(5) without scoping clarity.
   Fix: State explicitly whether SA-5(5) covers only source repositories or also embedded source delivered into your environment. Keep SBOM and component governance under your separate software supply chain controls, but document the boundary. ²

2. Mistake: Relying on policy language without enforceable repo settings.
   Fix: Pair policy with branch protection and review rules; keep exported settings as evidence. ²

3. Mistake: No third-party code intake procedure.
   Fix: Add an intake checklist to procurement and SOW closeout so you always capture delivery and acceptance evidence. ²

4. Mistake: No exception path, so teams bypass controls informally.
   Fix: Create an emergency change path with time-bound approvals and after-action review evidence. ²

Enforcement context and risk implications

No public enforcement cases were provided in your source catalog for SA-5(5). Treat this as an assessment-readiness requirement: failure usually appears as audit findings, contract noncompliance, delayed Authority to Operate (ATO) decisions, or increased remediation scope when incidents occur and you cannot reconstruct code provenance. ²

A practical 30/60/90-day execution plan

Use phases so you can start immediately without inventing a rigid timeline that won’t fit your SDLC.

First 30 days (Immediate stabilization)

• Assign SA-5(5) owner(s) and publish the one-page control statement and scope. ¹
• Inventory in-scope repositories for your highest-impact systems.
• Turn on baseline repo protections for those systems (SSO, logging, branch protections, required reviews). ²
• Define the exception process for emergency changes and admin access.

Days 31–60 (Make it repeatable)

• Roll the repo baseline standard across remaining in-scope systems.
• Implement third-party source code intake checklist and embed it into procurement/SOW closeout steps. ²
• Create an evidence binder structure (or Daydream control workspace) mapping each required artifact to an owner and a refresh cadence. ¹

Days 61–90 (Audit-ready operations)

• Run an internal mini-assessment: sample repos, sample PRs, sample releases, and a third-party code delivery.
• Close gaps: admin sprawl, unmanaged repos, missing intake records.
• Formalize ongoing monitoring: periodic access reviews for repo admins and periodic spot checks that branch protections remain enabled. ²

Frequently Asked Questions

Does SA-5(5) require us to escrow source code from a third-party software provider?

The provided excerpt does not specify escrow. Treat escrow as a contractual risk decision: if you need source to maintain a critical system, define delivery and availability terms in the contract and operationalize intake and custody. ²

We use multiple Git platforms. Is that automatically noncompliant?

Multiple platforms can work if you apply consistent guardrails and can produce consistent evidence. The audit risk comes from inconsistent settings, unmanaged admin access, and missing logs across platforms. ²

What’s the minimum evidence set an auditor will accept?

Expect to show: scope and ownership, repo inventory, repo configuration controls (branch protections/reviews/logging), samples of reviewed changes, and traceability from code to release. Keep third-party intake records when contractors deliver code. ¹

Does this apply to infrastructure-as-code and CI/CD pipeline code?

If pipeline or IaC code can change production behavior, include it in scope and apply the same governance: controlled repos, access control, review, and release traceability. Document the boundary so assessors can test it. ²

How do we handle emergency fixes that need to bypass normal review?

Define a break-glass path with named approvers, time-bound access, and an after-the-fact review recorded in a ticket. Keep that ticket as evidence and sample it during audits. ²

Where does Daydream fit without adding process overhead to engineering?

Use Daydream to assign SA-5(5) ownership, map required artifacts to evidence owners, and schedule recurring evidence pulls (repo settings exports, access reviews, change samples). Engineering keeps its workflow; GRC gets consistent audit-ready output. ¹

Footnotes

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

2. NIST SP 800-53 Rev. 5