BSI C5:2020·Criterion OPS-13·high·Component: Operations Security

What this control requires

Automatically monitors log data for events violating protection goals, including event correlations. Reports identified events to responsible departments for prompt evaluation and action, ensuring timely response to threats to cloud customer data.
— BSI C5:2020, Criterion OPS-13

In plain English

Automatically monitors log data for events violating protection goals, including event correlations. In practice, this means you can prove you review protection-level controls on a defined cadence.

Why it matters

BSI C5 is the default cloud-security baseline German public-sector buyers and many DAX-listed enterprises expect; gaps here directly block procurement in the DACH region and frequently appear as must-have items in EU public-tender documents.

This control is rated high. Auditors expect a named owner, a remediation SLA, and a tooling artefact that evidences continuous operation.

What an auditor looks for

A C5 attesting auditor (under ISAE 3000 / IDW PS 860) tests both the design and — for a Type 2 — the operating effectiveness over the attestation period. For each criterion they look for both the Basic and any in-scope Additional objectives.

Within Operations Security, the assessor will trace your implementation back to the catalogue reference (Criterion OPS-13) and look for objective evidence on the latest two assessment cycles.

How to implement

Logging Monitoring

AWS. Org-trail CloudTrail to a central log archive account, GuardDuty in every region, and Security Hub for cross-source correlation.

Azure. Pipe every diagnostic setting into a central Log Analytics workspace; onboard Microsoft Sentinel for SIEM/SOAR.

GCP. Aggregate audit logs in a dedicated logging project with sink to BigQuery; enable Security Command Center Premium and route findings to Chronicle SIEM.

Secure Development

Pipeline. Require code review, SAST (Semgrep / Snyk Code), SCA (Dependabot / Renovate), secret-scanning and IaC scanning in the merge pipeline.

Branch protection. Protected branches enforce reviews, signed commits and passing CI before merge; document the protection rules as the control evidence.

Code Review Testing

Pipeline. Require at least one human reviewer plus passing CI (lint, type, unit, security scan) before merge — protected branches enforce this.

Operational checklist

  • Review. Document the trigger, the owner and the cadence.
  • Security. Document the trigger, the owner and the cadence.
  • Protection. Document the trigger, the owner and the cadence.
  • Data. Document the trigger, the owner and the cadence.
  • Secure. Document the trigger, the owner and the cadence.
  • Scope: protection, event correlations, cloud customer data, development.

Evidence to collect

  • Code Repo Scan. Source-control evidence — branch protection, required reviewers, CI status, SCA / SAST reports.
  • Infra Scan. Continuous infrastructure-posture telemetry — AWS Config, Azure Policy compliance, GCP Organisation Policy, Wiz / Prisma findings.

Source control pipelines (GitHub, GitLab) enforce SDLC guardrails. Focus: Logging and Monitoring - Identification of Events.

Common pitfalls

  • Per-account logging that nobody stitches together at the org level — incidents that cross accounts go undetected for days.
  • CI security checks set to warn-only; the merge button is faster than the security feedback.

How it maps to other frameworks

Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.

Related controls in BSI C5:2020

References

Topics: logging monitoringsecure developmentcode review testingdevsecops