SA-3: System Development Life Cycle

To meet the sa-3: system development life cycle requirement, you must run acquisition, development, and ongoing management of each system through a defined SDLC method that explicitly embeds security and privacy work in every phase (requirements through retirement), with auditable evidence. Operationalize SA-3 by mapping ownership, gated SDLC activities, and recurring artifacts to each system and release.

Key takeaways:

• SA-3 expects a defined SDLC that bakes in security and privacy, not a separate “security review” at the end. ¹
• Auditors look for repeatable gates, clear ownership, and artifacts that show security/privacy were considered for real changes. ²
• Your fastest path is a system-by-system SA-3 control map: owner, SDLC procedure, and evidence pack. ¹

SA-3 sits in the NIST SP 800-53 “System and Services Acquisition” family and is one of the controls that separates “we build securely” from “we have security policies.” The requirement is simple on paper: acquire, develop, and manage systems using an SDLC approach that incorporates information security and privacy considerations. ¹ In practice, SA-3 becomes the spine that ties together your engineering workflow (product requirements, architecture, code, CI/CD, and change management) with your governance workflow (risk decisions, approvals, and evidence).

For a Compliance Officer, CCO, or GRC lead, the goal is fast operational clarity: what exactly must exist, who owns it, and what proof you retain so an assessor can confirm security and privacy are integrated into how systems are built and changed. SA-3 does not require a single “perfect” SDLC framework. It requires a consistent method that you can explain, follow, and evidence across the system lifecycle. ²

If you handle federal data directly or as a contractor, SA-3 commonly becomes a control that must be demonstrably implemented across in-scope systems, not just documented at an enterprise level. ²

Regulatory text

Requirement (verbatim excerpt): “Acquire, develop, and manage the system using {{ insert: param, sa-03_odp }} that incorporates information security and privacy considerations;” ¹

Operator interpretation of what you must do:

• Use a defined SDLC method for how you acquire/build and maintain systems (your “how we do engineering” approach). ²
• Embed security and privacy considerations into that SDLC, meaning they appear as required activities and decision points across phases (requirements, design, build, test, deploy, operate, change, retire). ¹
• Be able to show evidence that the SDLC method is followed for real work, not just described in a policy. ²

Practical reading: SA-3 is a “how you build and change systems” control, not a one-time compliance memo.

Plain-English requirement meaning

SA-3 requires that your organization’s SDLC includes security and privacy as standard engineering work. Security and privacy must show up as:

• Inputs (requirements, risk acceptance criteria, data classification),
• Activities (threat modeling, secure design review, security testing),
• Outputs (approved designs, test results, change records),
• Approvals (gates before deployment, documented risk decisions),
• Ongoing management (patching, vulnerability handling, lifecycle end-of-life planning). ²

Who it applies to (entity + operational context)

SA-3 is typically applied wherever NIST SP 800-53 is the control baseline, including:

• Federal information systems and the programs operating them. ²
• Contractor systems handling federal data, including systems used to deliver services to federal agencies or process/store federal information. ²

Operationally, SA-3 applies to:

• Systems you build (custom apps, internal services, infrastructure-as-code).
• Systems you configure heavily (SaaS with significant workflows/integrations).
• Systems you acquire (COTS products, managed platforms) where your responsibility is to ensure the acquisition and onboarding lifecycle includes security/privacy reviews and ongoing management. ²

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

1) Set SA-3 ownership and scope

• Assign a control owner (often Engineering Governance, Security, or GRC) and an operator owner (e.g., Head of Engineering or Platform lead).
• Define in-scope systems: systems subject to your NIST baseline, including major components and integrations. ²

Deliverable: SA-3 control record with owners, scope statement, and system inventory linkage.
Daydream tip: Start by mapping SA-3 to an owner, an implementation procedure, and a recurring evidence list so you can collect proof continuously instead of at audit time. ¹

2) Choose and document your SDLC method (as-operated)

Write a short SDLC standard that reflects reality, such as:

• Agile + CI/CD with defined security gates, or
• Hybrid with formal design reviews for higher-risk changes.

Include minimum required phases and how work moves:

• Intake → requirements → design → build → test → deploy → operate/change → retire. ²

Deliverable: “SDLC Standard” (2–6 pages) plus links to tooling workflows (Jira, GitHub, GitLab, Azure DevOps).

3) Embed security and privacy activities as SDLC gates

Define gates that must be satisfied before promotion to the next stage. Example structure:

• Requirements gate: data types identified; privacy impact considered; security requirements captured for the feature/system.
• Design gate: architecture review; threat model or risk analysis for material changes; logging/auth requirements defined.
• Build gate: secure coding expectations; secrets handling; dependency policy acknowledged.
• Test gate: security testing evidence appropriate to the change (SAST/DAST where applicable); remediation tracked.
• Deploy gate: change approval; rollback plan; risk acceptance if issues remain open.
• Operate gate: vulnerability triage process active; patching ownership set; incident hooks tested. ²

Control design rule: gates must be mandatory for in-scope releases, and exceptions must be tracked as risk decisions.

4) Tailor gates by risk, but document the tailoring logic

Auditors accept tailoring if it is consistent. Define categories such as:

• New system build
• Major architecture change
• Standard feature change
• Configuration-only change

For each category, define which SDLC security/privacy activities are required, optional, or not applicable, and what constitutes evidence.

Deliverable: “SDLC Security & Privacy Gate Matrix” (table format) referenced by the SDLC Standard. ²

5) Integrate third party acquisition into the same lifecycle

For acquired systems and third party services:

• Treat selection, contracting, onboarding, and major upgrades as SDLC events.
• Require security/privacy inputs at procurement time (minimum security requirements, data processing terms, integration review).
• Ensure ongoing management includes patching, configuration drift monitoring, and exit/retirement planning. ²

Deliverable: procurement/onboarding checklist mapped to SDLC gates for acquired components.

6) Make evidence collection automatic and repeatable

Attach evidence collection to existing tools:

• Ticket templates that require security/privacy fields
• Pull request templates requiring threat model link for defined triggers
• Release checklists with required attachments
• Central repository for “audit packets” per system/release ²

Daydream workflow option: Use Daydream to maintain the SA-3 requirement mapping (owner, procedure, evidence) and to generate an assessor-ready evidence request list by system and release train. ¹

Required evidence and artifacts to retain

Keep artifacts at two levels: program-level (the SDLC method) and execution-level (proof you followed it).

Program-level artifacts

• SDLC Standard document and version history
• SDLC Security & Privacy Gate Matrix (tailoring rules)
• Roles and responsibilities (RACI) for SDLC gates and approvals
• List of in-scope systems and how the SDLC applies to each ²

Execution-level artifacts (sample set)

• Requirements tickets showing security/privacy requirements or data handling notes
• Architecture/design review records for major changes
• Threat models or risk analyses where triggered
• Security testing outputs (tool reports or summarized results) and remediation tickets
• Change/release approvals and deployment records
• Risk acceptances with approver, scope, and expiration/reevaluation trigger
• Evidence of ongoing management (vulnerability triage records, patch/change logs) ²

Retention practice: store by system and by release so you can answer “show me for this system, this change.”

Common exam/audit questions and hangups

Auditors commonly probe:

• “Show your SDLC and where security and privacy are required.” ²
• “Provide examples from the last few releases showing the gates were followed.”
• “How do you decide when threat modeling is required?”
• “How are third party products brought in, assessed, and managed over time?”
• “Who can approve exceptions, and how do you track them?” ²

Hangups that create findings:

• SDLC policy exists, but engineering teams can bypass it with no detection.
• Security testing tools exist, but results are not reviewed or tracked to closure.
• “Privacy considerations” are asserted in narrative form with no workflow touchpoints. ¹

Frequent implementation mistakes (and how to avoid them)

1. Writing an SDLC that doesn’t match reality
   Fix: document the SDLC you actually run, then add incremental gates that engineering can meet consistently. ²

2. One-size-fits-all gates that create constant exceptions
   Fix: create a tailoring matrix and define triggers for “high ceremony” steps (architecture review, threat modeling). Exceptions should be rare.

3. Treating SA-3 as “DevSecOps tooling deployed”
   Fix: tooling helps, but SA-3 is about lifecycle governance. Require human review and explicit decisions where risk exists. ²

4. No evidence packaging strategy
   Fix: define an “SA-3 evidence pack” per system/release and collect artifacts continuously. Daydream-style mapping of owner/procedure/artifacts reduces scramble work. ¹

Risk implications (what goes wrong if SA-3 is weak)

A weak SA-3 posture typically produces:

• Inconsistent security controls across systems and releases
• Late discovery of design flaws (authn/authz gaps, insecure data flows)
• Poor traceability for risk decisions and exceptions
• Higher operational risk from unmanaged dependencies and third party components ²

Even without a named enforcement case in your source pack, assessors treat SDLC controls as foundational because they affect many other control families (change management, vulnerability management, configuration, incident response) through the same delivery pipeline. ²

Practical 30/60/90-day execution plan

First 30 days (stabilize and scope)

• Name SA-3 control owner and engineering operator owner.
• Inventory in-scope systems and identify their SDLC path (custom, configured SaaS, acquired).
• Draft SDLC Standard that matches current practice; document current gates.
• Define the initial evidence pack list and where it will be stored. ²

Days 31–60 (add gates + tailoring)

• Publish the SDLC Security & Privacy Gate Matrix (triggers and minimum artifacts).
• Update ticket/PR/release templates to capture required fields and links.
• Pilot on a small number of systems or one release train; collect evidence end-to-end.
• Define exception/risk acceptance workflow with approvers and tracking. ²

Days 61–90 (prove operation + harden)

• Expand to remaining in-scope systems.
• Run an internal “mini-assessment”: pick recent changes and assemble the SA-3 evidence packet.
• Close gaps: missing design reviews, inconsistent testing evidence, unclear privacy steps.
• Operationalize reporting: recurring check that gates are met and exceptions are reviewed. ²

Frequently Asked Questions

Do we need a formal “waterfall” SDLC to satisfy SA-3?

No. SA-3 expects a defined method you follow, and that security and privacy are embedded within it. Agile and CI/CD can meet SA-3 if the gates and evidence are consistent. ²

What counts as “privacy considerations” for SA-3?

Treat privacy like a required input and approval point: identify sensitive data, document intended use/disclosure, and capture design decisions that reduce exposure. Evidence should exist in requirements and design artifacts for applicable changes. ¹

How do we handle acquired systems and third party services under SA-3?

Bring acquisition and onboarding into your lifecycle: security/privacy requirements at selection, integration review before go-live, and ongoing management (updates, configuration, deprovisioning) after. Keep the same gate-and-evidence approach you use for internal builds. ²

What evidence is most persuasive to an assessor?

Real change samples: tickets, design reviews, testing outputs, and deployment approvals that show the gates were followed for specific releases. Program documents help, but execution artifacts usually decide the outcome. ²

How do we prevent “checkbox” security gates that engineers bypass?

Make gates part of the workflow (templates, required fields, release checklists) and require an approval trail for exceptions. If bypass is possible, auditors will treat the gate as non-operational. ²

Where does Daydream fit without adding process overhead?

Use Daydream to keep the SA-3 mapping tight: control owner, SDLC procedure reference, and recurring evidence artifacts per system. That reduces audit scramble and helps you spot which systems lack usable SDLC evidence. ¹

Footnotes

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

2. NIST SP 800-53 Rev. 5