BSI C5:2020 SIM-03 — Documentation and reporting of security incidents

What this control requires

Documents incident resolutions and reports to affected customers per agreements for acknowledgment. Ensures transparency and accountability, enabling customers to verify incident handling and maintain trust in cloud data security.

In plain English

Documents incident resolutions and reports to affected customers per agreements for acknowledgment. In practice, this means you can prove you documentation, agreements-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 Security Incident Management, the assessor will trace your implementation back to the catalogue reference (Criterion SIM-03) and look for objective evidence on the latest two assessment cycles.

How to implement

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.

Cloud Posture

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

Policy Management

Docs. Keep each policy in version-controlled Markdown alongside the code that implements it; ship a signed PDF snapshot at each annual review and link the SHA into the SoA.

Operational checklist

• Documentation,. 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.
• Policy. Document the trigger, the owner and the cadence.
• Scope: agreements, - accountability, security incident management, security incidents.

Evidence to collect

• Ticketing Workflow. ticketing_workflow evidence

Workflow metrics (ServiceNow, Jira) show approvals and remediation. Focus: Documentation and reporting of security incidents.

Common pitfalls

• Runbooks that name a role but no person, or list a paging channel that no longer exists.
• Treating CSPM findings as a backlog instead of a hot queue: findings older than the policy SLA accumulate until the auditor asks why.
• Policies that no engineer has read; the version in Confluence drifts from the version that's actually being enforced.

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.

• ISO/IEC 27001:2022 A.5.27 — Learning from information security incidents
• NIST SP 800-53 Rev. 5 IR-6 — Incident Reporting
• NIST SP 800-171 Rev. 3 3.6.2 — Incident Monitoring, Reporting, and Response Assistance
• CIS Controls v8 17.4 — Establish and Maintain an Incident Response Process
• SOC 2 (2017 TSC) CC7.4 — Incident Response

Related controls in BSI C5:2020

• Criterion SIM-04 — Duty of the users to report security incidents to a central body
• Criterion SIM-01 — Policy for security incident management
• Criterion SIM-05 — Evaluation and learning process
• Criterion OPS-21 — Involvement of Cloud customers in the event of incidents
• Criterion SIM-02 — Processing of security incidents
• Criterion OPS-15 — Logging and Monitoring - Accountability

References

• Bundesamt für Sicherheit in der Informationstechnik (BSI) — BSI C5:2020
• Catalogue identifier: Criterion SIM-03

Topics: incident responsechange managementcloud posturepolicy management