SOC 2 vs ISO 27001 — Choose in 5 Questions

When a customer asks for “security proof,” they usually mean SOC 2 or ISO/IEC 27001. Both are credible, but they differ in audience, scope, output, and audit style. Use this guide to choose quickly—and set yourself up to reuse most of the evidence no matter which path you take.

The 30-second primer

• SOC 2 (AICPA): Attestation report against the Trust Services Criteria (Security, Availability, Confidentiality, Processing Integrity, Privacy).
  • Type I: point-in-time design effectiveness.
  • Type II: operating effectiveness over a period (commonly 6–12 months).
  • Output: auditor’s report, not a certificate.
• ISO/IEC 27001: Certifies your ISMS (Information Security Management System) via an accredited certification body.
  • Focus on risk management + Annex A control set (2022 version).
  • Output: internationally recognized certificate (3-year cycle with annual surveillance).

Choose in 5 questions

1. Who’s your buyer?
   • Mostly US enterprise/SaaS? → They typically ask for SOC 2 first.
   • Global, public sector, regulated, or EU/APAC buyers? → They favor ISO 27001.
2. What proof do they expect?
   • “Send the SOC 2 Type II report” is a common vendor-security prerequisite in US deals.
   • “Provide an ISO 27001 certificate” is often required for tenders, public sector, or global frameworks.
3. How do you want to scope?
   • Service/system-level scope with flexibility → SOC 2.
   • Organization-wide ISMS with risk register, objectives, internal audits → ISO 27001.
4. Evidence style & cadence?
   • SOC 2 Type II: continuous controls working over 6–12 months; one detailed report for customers under NDA.
   • ISO 27001: formal ISMS + risk treatment; Stage 1 & 2 certification, then annual surveillance audits.
5. Commercial timeline pressure?
   • Need faster sales unblock? Start SOC 2 Type I (then Type II).
   • Need global credibility for RFPs and frameworks? Start ISO 27001.

Rule of thumb: US B2B SaaS starts with SOC 2 Type II; multinational/regulated environments prioritize ISO 27001. Many mature orgs do both over 12–24 months.

Mapping the controls (so you don’t duplicate work)

Whether you pick SOC 2 or ISO 27001 first, build these reusable foundations:

• Governance: Security policy set, ISMS/InfoSec charter, roles and responsibilities.
• Risk Management: Asset inventory, risk register, treatment plan, Statement of Applicability (ISO) or criteria mapping (SOC 2).
• Access Control: Joiner-Mover-Leaver, least privilege, MFA, privileged access, periodic reviews.
• Secure Operations: Logging/monitoring, vulnerability management, patching, malware/EDR, backup & restore testing.
• Change & SDLC: Change management, code reviews, CI/CD controls, secrets management, dependency scanning.
• Supplier Management: Vendor due diligence, contract clauses, monitoring, exit plans.
• Incident Response: Runbook, roles, tabletop tests, regulatory/breach notifications.
• Business Continuity/DR: RTO/RPO, tested restores, DR exercises.
• People & Awareness: Background checks (where lawful), training, acceptable use, disciplinary process.
• Privacy & Data Lifecycle: Classification, retention, DLP, data subject rights workflow (if in scope).

Implement once, evidence twice: the same tickets, screenshots, configs, logs, and training records support both standards.

Scope, effort, and timelines (realistic view)

• SOC 2 Type I: 4–10 weeks of prep, then a point-in-time audit.
• SOC 2 Type II: add an observation window (6–12 months). Plan backwards from your sales season.
• ISO 27001:
  • Design/implement ISMS: 8–16 weeks (small/medium orgs).
  • Stage 1 (readiness/document review): ~1–3 days.
  • Stage 2 (certification audit): ~3–7+ days depending on size/scope.
  • Surveillance audits: 1–2 days annually in years 2–3.

Your bottlenecks will be: asset inventory, risk register quality, access reviews, supplier evidence, and proving that controls actually run (not just written down).

Decision guide (quick matrix)

Doing both (without the pain)

1. Start with the ISMS basics (risk register, asset inventory, policy set).
2. Use those artifacts to pass SOC 2 Type I, then operate controls for Type II.
3. In parallel, mature the ISMS (internal audits, objectives, metrics) and schedule ISO 27001 Stage 1 → Stage 2.
4. Keep a single control library with mappings to: SOC 2 TSC ↔ ISO 27001 Annex A.
5. Run one quarterly evidence sprint and feed both programs.

What auditors actually look for (and how to prepare)

• Consistency over time: tickets, change logs, patch windows, alert closures.
• Access reviews with decisions: keep/remove/downgrade; capture approvals.
• Vendor proofs: SOC 2/ISO certificates from suppliers, DPAs, penetration test summaries.
• IR drills: tabletop notes, lessons learned, updated runbooks.
• BC/DR realism: restore test screenshots, RTO/RPO achieved, remediation actions.

Create a “customer security pack”: policy excerpts, network diagrams, data flow, sub-processors, encryption descriptions, incident process, business continuity summary, and your SOC 2 or ISO certificate/report cover letter.

Common pitfalls to avoid

• Paper ISMS: policies exist, controls don’t run. Fix with quarterly control checks.
• Over-scoping: certify everything at once. Start with the product/org slice customers buy.
• Under-evidencing: no screenshots, no logs, no approvals. Treat evidence like a product.
• Identity drift: weak JML, no periodic access reviews, ghost admins.
• Vendor blind spots: unvetted sub-processors or missing SLAs/backups.
• One-and-done mindset: both standards expect continuous improvement.

30-60-90 day starter plan

Days 0–30 (Foundations)

• Appoint an ISMS owner and executive sponsor.
• Build asset inventory, risk register, and a minimal policy set.
• Lock in MFA everywhere, logging, patch cadence, backups with restore test.

Days 31–60 (Operate & Evidence)

• Run access reviews; fix over-privileged roles.
• Implement vendor due diligence and a third-party register.
• Dry-run an incident tabletop; record outcomes.
• Decide path: SOC 2 Type I or ISO 27001 first; schedule auditor/cert body.

Days 61–90 (Audit-ready)

• Finalize control mappings (SOC 2 TSC ↔ ISO 27001 Annex A).
• Assemble an evidence pack: tickets, screenshots, logs, change records.
• Conduct internal audit/management review (ISO) or readiness assessment (SOC 2).
• Start observation window (SOC 2 Type II) or Stage 1 (ISO 27001).

FAQ (quick hits)

• Do customers accept SOC 2 instead of ISO?
  Often in the US yes; globally or in regulated tenders, ISO 27001 is frequently mandatory.
• Can we share the SOC 2 report publicly?
  No; it’s under NDA. Create a security overview and share the full report on request.
• How long should the SOC 2 period be?
  Aim for 6–12 months; many buyers prefer 12. Your first cycle can be 6 to reach market sooner.
• Is ISO 27001 only for big companies?
  No. Small firms certify successfully with a lean ISMS that fits their risk.

Bottom line

Pick the path that gets you to revenue and trust fastest, but build a single control system that can satisfy both SOC 2 and ISO 2701 with shared evidence. Think in quarters, not years; run the controls, gather proof, improve, repeat.

If you want help choosing the fastest route and building a reusable evidence pack, see Imagis – Managed Security & Compliance (we’ll map your buyers, timeline, and controls, then execute).