---
name: iso-27001-internal-audit
description: >-
  Run an ISO 27001 internal audit. Walk through controls by domain, identify
  gaps, collect evidence, and generate findings with corrective action
  recommendations. Uses NIST SP 800-53 (public domain) as canonical reference.
  Use when user says "run internal audit," "ISO 27001 audit," "control
  assessment," "audit findings," or "ISMS assessment."
license: Apache-2.0
compatibility: >-
  Works with any AI agent. Enhanced with compliance MCP server for live
  dashboard data. Falls back to embedded reference files when no live data
  is available.
metadata:
  author: open-agreements
  version: "0.1.0"
  frameworks:
    - ISO 27001:2022
    - SOC 2 Type II
    - NIST SP 800-53 Rev 5
catalog_group: Compliance And Audit
catalog_order: 20
---

# ISO 27001 Internal Audit

Run a structured internal audit against ISO 27001:2022. This skill walks you through scoping, control assessment, evidence collection, and findings generation — following the same workflow a certified auditor uses.

## Security Model

- **No scripts executed** — this skill is markdown-only procedural guidance
- **No secrets required** — works with public reference data
- **IP-clean** — all control descriptions are original writing referencing NIST SP 800-53 (public domain). ISO 27001:2022 controls are referenced by section ID only (e.g., "A.5.15"), never by copyrighted title or description
- **Evidence stays local** — all evidence collection commands output to local filesystem

## When to Use

Activate this skill when:

1. **Preparing for a surveillance or certification audit** — run 4-6 weeks before the external audit
2. **Performing quarterly internal audit** — ISO 27001 requires at least annual internal audits; quarterly is best practice
3. **Post-incident review** — assess whether controls failed and what corrective actions are needed
4. **New framework adoption** — map existing controls to ISO 27001 requirements
5. **Onboarding a new compliance tool** — validate that automated checks cover the right controls

Do NOT use for:
- Generating the ISO 27001 Statement of Applicability (SoA) from scratch — use `iso-27001-evidence-collection` for evidence gathering first
- SOC 2-only audits — use `soc2-readiness` instead
- Reading or interpreting a specific contract clause — use legal agreement skills

## Core Concepts

### Control Domains (ISO 27001:2022 Annex A)

ISO 27001:2022 has 93 Annex A controls across 4 domains, plus ISMS clauses 4-10 (30 sub-clauses). This skill covers **48 priority Annex A controls** (of 93 total) — the most critical per domain for cloud-native startups. Remaining controls are lower-tier or typically N/A for cloud-native organizations.

| Domain | Controls | Focus |
|--------|----------|-------|
| A.5 Organizational | 37 | Policies, roles, incident management, supplier relations |
| A.6 People | 8 | Screening, training, termination, confidentiality |
| A.7 Physical | 14 | Facility security, equipment, media — mostly N/A for cloud startups |
| A.8 Technological | 34 | Access control, crypto, logging, SDLC, network security |
| Clauses 4-10 | 30 | ISMS management system (context, leadership, planning, support, operation, performance, improvement) |

### Decision Tree: Startup Scoping

```
Is the organization cloud-native (no owned data centers)?
├── YES → Mark A.7.1-A.7.9, A.7.11-A.7.13 as "satisfied by cloud provider SOC 2"
│         Focus evidence on: laptops, home offices, mobile devices
├── NO  → Full A.7 assessment required
│
Does the organization develop software?
├── YES → A.8.25-A.8.34 (SDLC controls) are in scope
├── NO  → A.8.25-A.8.34 can be scoped out with justification
│
Does the organization handle PII?
├── YES → A.5.34 (privacy) is critical, cross-reference with GDPR/CCPA
├── NO  → A.5.34 is checkbox tier
```

### Control Tiering

Not all 93 controls fail equally. Prioritize by audit failure frequency:

| Tier | Count | Treatment |
|------|-------|-----------|
| **Critical** | ~30 | Full assessment: evidence, interviews, observation |
| **Relevant** | ~30 | Standard check: evidence review, spot-check |
| **Checkbox** | ~33 | Verify policy exists or cloud provider covers it |

For detailed per-control guidance, load `rules/<domain>.md`.

## Step-by-Step Workflow

### Step 1: Scope and Context

1. **Identify the ISMS scope** — What systems, processes, locations, and people are in scope?
2. **Gather the Statement of Applicability (SoA)** — Which of the 93 Annex A controls apply?
3. **Review previous audit findings** — What was flagged last time? Are corrective actions closed?
4. **Check data freshness** — If using a monitoring dashboard or automated testing system, verify data is < 7 days old

```
# If Internal ISO Audit MCP server is available:
list_controls()                                    # Get all controls with tier classifications
get_control_guidance(control_id="Clause 9.2")      # Check specific ISMS clause requirements

# If reading local files:
# Check compliance/status/last_refresh.yaml for staleness
```

### Step 2: ISMS Clause Assessment (Clauses 4-10)

Most startups fail here — they treat ISMS as documentation, not a functioning management system.

1. **Clause 5 (Leadership)** — Is there a signed security policy? Who is the ISMS owner? Is there evidence of management review?
2. **Clause 6 (Planning)** — Is there a risk assessment? Is it current (< 12 months)? Does it reference the SoA?
3. **Clause 7 (Support)** — Is there a competence matrix? Are training records current?
4. **Clause 8 (Operation)** — Is the risk treatment plan being executed?
5. **Clause 9 (Performance)** — Are there metrics? Has an internal audit been done? Is there a management review record?
6. **Clause 10 (Improvement)** — Are nonconformities tracked? Are corrective actions implemented?

**Auditor hint**: Auditors look for a CONNECTED chain — risk assessment → SoA → risk treatment plan → evidence of implementation → monitoring → management review → improvement. Any break in the chain is a nonconformity.

### Step 3: Annex A Control Assessment

Work through controls by domain, prioritizing Critical tier:

1. **For each Critical control**:
   - Check: Is there a documented policy/procedure?
   - Check: Is there evidence of implementation?
   - Check: Is there evidence of monitoring/review?
   - Record finding: Conformity / Minor nonconformity / Major nonconformity / Observation

2. **For each Relevant control**:
   - Check: Is there evidence of implementation?
   - Spot-check one or two items
   - Record finding

3. **For each Checkbox control**:
   - Verify policy exists or cloud provider SOC 2 covers it
   - Record as conforming or note exception

```
# If Internal ISO Audit MCP server is available:
list_controls(domain="organizational")                      # List all controls in a domain with tiers
get_control_guidance(control_id="A.5.15")                   # Full guidance: auditor hints, pitfalls, evidence
search_guidance(query="access review", domain="organizational")  # Find related controls by keyword
get_nist_mapping(control_id="A.5.15")                       # Cross-reference to NIST SP 800-53
```

### Step 4: Evidence Collection

For each finding, collect supporting evidence:

1. **API exports** (preferred) — timestamped JSON/CSV from source systems
2. **Screenshots** (when API unavailable) — must include visible system clock
3. **Interview notes** — summarize who said what, when
4. **Document review** — note document name, version, date reviewed

**Evidence naming convention**: `{control_id}_{evidence_type}_{date}.{ext}`
Example: `A.5.15_user-access-list_2026-02-28.json`

For detailed collection commands, load `rules/` files or use the `iso-27001-evidence-collection` skill.

### Step 5: Generate Findings

For each nonconformity:

```markdown
## Finding: [Short title]

- **Control**: A.x.x
- **NIST Reference**: [NIST control ID]
- **Severity**: Major / Minor / Observation
- **Description**: [What was found]
- **Evidence**: [What evidence supports the finding]
- **Root Cause**: [Why the control failed]
- **Corrective Action**: [Specific remediation steps]
- **Due Date**: [Agreed timeline]
- **Owner**: [Person responsible]
```

**Severity definitions**:
- **Major nonconformity**: Control is missing or completely ineffective. Audit failure risk.
- **Minor nonconformity**: Control exists but has gaps. Must fix before next surveillance audit.
- **Observation**: Potential improvement. Not required but recommended.

### Step 6: Audit Report

Generate a structured audit report:

1. **Executive summary** — overall ISMS maturity, key findings, recommendation
2. **Scope** — what was audited, what was excluded
3. **Methodology** — controls assessed, evidence reviewed, people interviewed
4. **Findings** — grouped by domain, with severity and corrective actions
5. **Positive observations** — what's working well (auditors do note these)
6. **Conclusion** — readiness for external audit, recommended timeline

## Quick Reference: Top 10 Controls That Fail Most Often

| # | Control | Common Failure | Fix |
|---|---------|---------------|-----|
| 1 | A.5.15 | No periodic access review | Schedule quarterly reviews, export user lists |
| 2 | A.8.8 | No vulnerability scanning | Deploy Dependabot/Snyk, schedule infra scans |
| 3 | A.5.24 | Incident response plan untested | Run tabletop exercise, document results |
| 4 | A.8.5 | MFA not enforced everywhere | Enable MFA on all production + admin accounts |
| 5 | A.5.30 | No business continuity test | Run DR failover test, document RTO/RPO results |
| 6 | A.8.15 | Audit logs not centralized | Ship logs to SIEM/CloudWatch/Stackdriver |
| 7 | A.8.9 | No baseline configuration | Document server/container base images |
| 8 | A.6.1 | Background checks incomplete | Verify all employees have completed screening |
| 9 | A.8.32 | No change management process | Require PR reviews, document deployment process |
| 10 | A.5.9 | Asset inventory incomplete | Export from cloud provider + endpoint management |

## DO / DON'T

### DO
- Collect evidence via API exports with ISO 8601 timestamps — always preferred over screenshots
- Test controls, don't just review documentation — auditors check implementation, not just policies
- Interview people at different levels — manager says one thing, engineer may say another
- Document positive findings — shows the audit is balanced and thorough
- Keep the SoA aligned with actual controls — gaps between SoA and implementation are major findings
- Use `screencapture -x ~/evidence/{filename}.png` on macOS when screenshots are necessary

### DON'T
- Screenshot portals without visible system clock — auditors will reject undated evidence
- Accept "we have a policy" without checking implementation — "show me" > "tell me"
- Audit your own work — independence requirement (Clause 9.2) means auditors can't audit their own area
- Treat checkbox controls as zero-effort — even N/A controls need justification in the SoA
- Skip ISMS clauses to focus only on Annex A — most first-time failures are in clauses 4-10

## Troubleshooting

| Problem | Solution |
|---------|----------|
| Data is stale (> 7 days old) | Refresh from monitoring dashboard or re-export from source systems |
| Can't determine which controls apply | Start with the SoA; if no SoA exists, use the decision tree above |
| Too many findings to address before audit | Prioritize: fix all Major nonconformities first, then Critical-tier Minors |
| Evidence timestamps don't match audit period | Re-collect evidence within the audit window (typically 12 months) |
| Cloud provider controls not documented | Request SOC 2 Type II report from provider; map their controls to your SoA |
| Internal audit has never been done | This IS the first internal audit — document that in the report and plan for regular cadence |

## Rules

For detailed per-control guidance, load the appropriate rules file:

| File | Coverage |
|------|----------|
| `rules/access-control.md` | A.5.15-A.5.18, A.8.2-A.8.5 — identity, authentication, authorization |
| `rules/incident-response.md` | A.5.24-A.5.29, A.6.8 — incident lifecycle |
| `rules/encryption.md` | A.8.24, A.8.10-A.8.12 — cryptographic controls |
| `rules/change-management.md` | A.8.25-A.8.34, A.8.9, A.8.32 — SDLC and configuration |
| `rules/logging-monitoring.md` | A.8.15-A.8.17 — audit trails and monitoring |
| `rules/business-continuity.md` | A.5.30, A.8.13-A.8.14 — backup, DR, BCP |
| `rules/people-controls.md` | A.6.1-A.6.8 — HR security lifecycle |
| `rules/supplier-management.md` | A.5.19-A.5.23 — third-party risk |
| `rules/isms-management.md` | Clauses 4-10 — management system operation |

## Attribution

Audit procedures and control guidance developed with [Internal ISO Audit](https://internalisoaudit.com) (Hazel Castro, ISO 27001 Lead Auditor, 14+ years, 100+ audits).

## Runtime Detection

This skill operates in three modes, detected automatically:

1. **Internal ISO Audit MCP server available** (best) — Live control guidance lookup with auditor hints, NIST cross-references, and full-text search
   - Detected by: `internalisoaudit` MCP server configured in client
   - Tools: `get_control_guidance`, `list_controls`, `get_nist_mapping`, `search_guidance`
   - Server: `internalisoaudit.com/api/mcp`

2. **Local compliance data available** (good) — Reads `compliance/` directory directly
   - Detected by: `compliance/status/last_refresh.yaml` exists
   - Benefits: Historical test data, evidence status, control mappings

3. **Reference only** (baseline) — Uses embedded `rules/` files, no live data
   - Always available
   - Benefits: Procedural guidance, control descriptions, evidence checklists
   - Limitation: No organization-specific status data

## Connectors

For Internal ISO Audit MCP server setup, see [CONNECTORS.md](./CONNECTORS.md).
