BSI C5:2020·Criterion OPS-20·high·Component: Operations Security

What this control requires

Quarterly evaluates vulnerability and incident handling procedures for effectiveness, initiating continuous improvements. Ensures robust processes to mitigate risks, maintaining the security and integrity of cloud customer data and services.
— BSI C5:2020, Criterion OPS-20

In plain English

Quarterly evaluates vulnerability and incident handling procedures for effectiveness, initiating continuous improvements. In practice, this means you can prove you risk cloud customer data-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-20) and look for objective evidence on the latest two assessment cycles.

How to implement

Vulnerability Management

Scanners. Pair an unauthenticated scanner (Nessus / Qualys / Tenable.io) for external surface with an authenticated agent for OS/library CVEs on every host.

SLA. Document remediation SLAs by CVSS / EPSS: critical 7 days, high 30 days, medium 90 days; report monthly trend to leadership.

Containers. Scan images in CI (Trivy / Grype / Snyk Container) AND at runtime; block deploys on critical findings without exception.

Cloud Posture

CSPM. Run Wiz / Prisma / Defender for Cloud / Security Command Center over every account; auto-ticket findings above your accepted-risk threshold.

Incident Response

Runbook. Maintain a runbook keyed by incident type with named roles (IC, comms, scribe), an out-of-band comms channel, and a 72-hour timeline for external notification.

Tabletop. Run a quarterly tabletop exercise (ransomware, insider, supply-chain) and feed gaps back into the runbook.

Operational checklist

  • Risk. Document the trigger, the owner and the cadence.
  • Security. Document the trigger, the owner and the cadence.
  • Data. Document the trigger, the owner and the cadence.
  • Scope: cloud customer data, management.

Evidence to collect

  • Policy Document. A signed and version-controlled policy / standard / procedure document.

Signed policy or standard documents the safeguard. Focus: Managing Vulnerabilities, Malfunctions and Errors - Measurements, Analyses and Assessments of Procedures.

Common pitfalls

  • Scans that hit only the perimeter; missing authenticated scans of OS, runtime libs and base images so most CVEs are invisible.
  • Treating CSPM findings as a backlog instead of a hot queue: findings older than the policy SLA accumulate until the auditor asks why.
  • Runbooks that name a role but no person, or list a paging channel that no longer exists.

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: governance riskvulnerability managementcloud posturecontinuous monitoringincident response