What is the difference between secure-by-design and secure-by-default in software procurement requirements?

Secure-by-design means security is built into the architecture, development process, and validation steps from the start. Secure-by-default means the shipped product is configured to minimise risk without requiring customers to harden it first. In procurement settings, the two work together, because buyers increasingly expect software that is both engineered securely and safe to deploy immediately.

What procurement language is really asking for

In procurement, secure-by-design and secure-by-default address two different layers of supplier responsibility. Secure-by-design is about how the product is engineered, tested, and maintained. Secure-by-default is about the state a buyer receives on day one, including whether unsafe features are off, privileges are minimal, and secure settings do not depend on customer hardening.

That distinction matters because a product can be well-designed internally but still arrive in a risky configuration, or it can ship with safer defaults while still lacking secure engineering discipline. Buyers should treat the terms as complementary, not interchangeable, when writing requirements, scoring responses, and checking delivery evidence. See CISA’s Secure by Design guidance for the broader product-security posture behind the term.

Where procurement teams get value is in separating claims about architecture and development from claims about deployment state. That helps avoid vague supplier answers such as “security is built in” when the real question is whether insecure features, default accounts, exposed admin interfaces, or permissive settings are removed before first use.

Why the difference changes supplier evaluation

Secure-by-design is the stronger test for whether the vendor has reduced defects and security debt upstream. It asks whether security requirements shaped threat modelling, coding, testing, patching, and release governance. Secure-by-default is the stronger test for whether the buyer can deploy the product with low initial exposure and without a long hardening project.

For procurement, this creates a practical split in evidence. Design claims should be supported by secure development practices, vulnerability handling, and release controls. Default claims should be supported by product configuration, installation baselines, and administrator documentation that shows the safest settings are also the usable settings. The EU Cyber Resilience Act is a useful reference point because it pushes both safer product engineering and safer lifecycle outcomes for products with digital elements.

Buyers should also distinguish between “secure by default” and “customers can make it secure after effort.” The second is a weak procurement answer. If the seller requires a long list of manual changes before the product is acceptable, then the default state is not genuinely secure, even if the product can be hardened later.

What good procurement requirements look like

Strong procurement language asks for both a secure engineering approach and a secure out-of-box state. A useful requirement set typically includes:

evidence that security requirements were designed into the product lifecycle, not added after release;
a secure installation profile with minimal privileges, disabled unnecessary services, and no unsafe default accounts or keys;
documented hardening guidance for optional features, integrations, and administrative access;
a vulnerability disclosure and patch process that supports continued secure operation;
verification that the buyer can deploy the product safely without undocumented tuning.

For application-heavy procurement, OWASP ASVS is useful as a verification lens because it translates secure engineering into testable expectations around authentication, access control, and validation. If the product also relies on certificate handling or trust relationships, the CA/Browser Forum requirements provide a good example of how default trust and revocation expectations are governed in a mature ecosystem.

Risk and Threat Considerations:

Procurement language that treats the two terms as synonyms can leave buyers exposed to products that are well marketed but poorly deployable. The failure mode is usually hidden configuration risk, where insecure defaults, excessive administrative access, or undeclared setup steps shift the burden of safety onto the customer.

Failure mechanism: The supplier may have secure engineering practices but still ship with permissive defaults, exposed management functions, or credential and privilege settings that create avoidable attack surface before the buyer performs any hardening.

Impact: The buyer inherits higher initial risk, longer deployment cycles, and a wider chance of misconfiguration, especially when operations teams assume the product is safe simply because it was described as secure-by-design.

Standards & Framework Alignment

This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.

OWASP Non-Human Identity Top 10 and OWASP Agentic AI Top 10 address the attack and risk surface, while NIST CSF 2.0, CIS Controls v8 and NIST SP 800-63 set the governance and control requirements practitioners need to meet.

Framework	Control / Reference	Relevance
NIST CSF 2.0	PR.IP — Information Protection Processes and Procedures	Secure-by-design depends on built-in secure development and release processes.
Recommendation — Establish secure development and release processes that keep security built into the product lifecycle.
CIS Controls v8	5 — Account Management	Secure-by-default requires safe shipped accounts and minimal initial access paths.
	4 — Secure Configuration of Enterprise Assets and Software	Secure-by-default is about the product's initial hardened configuration.
Recommendation — Remove unnecessary default accounts and enforce least-privilege account setup at deployment. Ship and verify secure baseline configurations before first use.
OWASP Non-Human Identity Top 10	NHI-01 — Secret Sprawl and Exposure	Products that ship with unsafe defaults often expose secrets or credentials unnecessarily.
	NHI-02 — Overprivileged Non-Human Identities	Default access models often grant excessive machine or service privileges at start.
Recommendation — Eliminate exposed secrets and default credentials from shipped configurations. Design service and machine access to start with minimal privilege and explicit scope.
NIST SP 800-63	IAL/AAL — Identity Assurance and Authenticator Assurance	Procurement often needs proof that authentication and identity controls are designed securely.
Recommendation — Require strong authentication and assurance evidence for user and administrative access.
OWASP Agentic AI Top 10	A2 — Identity and Access Abuse	If the product includes autonomous or tool-using agents, default access settings directly affect abuse risk.
Recommendation — Constrain agent and tool access so defaults do not permit unintended actions.

Practitioner Guidance

What to verify: Ask suppliers for both development evidence and deployment evidence. Development evidence should show how security influenced design, testing, and release approval. Deployment evidence should show the shipped configuration, not the hardened configuration, including whether the product starts with least privilege and no unnecessary exposure.

Decision rule: If the requirement is about what the buyer receives on first install, make secure-by-default explicit and testable. If the requirement is about how the supplier builds and maintains the product, make secure-by-design explicit and require lifecycle evidence. Do not accept one as a substitute for the other.

Practitioner takeaway: Good procurement separates product engineering quality from initial deployment safety, and the strongest contracts require both, because a secure architecture does not protect the buyer if the shipped defaults are still unsafe.