# BSI C5:2020 PS-03 — Perimeter Protection - Source: https://support.icompaas.com/compliance/bsi-c5-2020/ps-03-perimeter-protection - Section: [Compliance](https://support.icompaas.com/compliance) › [BSI C5:2020 (Cloud Computing Compliance Criteria)](https://support.icompaas.com/compliance/bsi-c5-2020) › Physical Security (PS) - Last updated: 2026-06-05 - Publisher: iCompaas, Inc. (https://www.icompaas.com) **BSI C5:2020**·Criterion `PS-03`·high·Component: **Physical Security** ## What this control requires > Ensures premises have robust structural shells and security measures per PS-01 to prevent unauthorized access. Uses solid doors, windows, and locks resisting burglary for 10 minutes, safeguarding cloud infrastructure and customer data from physical threats. > > — BSI C5:2020, Criterion PS-03 ### In plain English Ensures premises have robust structural shells and security measures per PS-01 to prevent unauthorized access. In practice, this means you can prove you security measures-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 **Physical Security**, the assessor will trace your implementation back to the catalogue reference (Criterion PS-03) and look for objective evidence on the latest two assessment cycles. ## How to implement #### Cloud Posture **CSPM.** Run Wiz / Prisma / Defender for Cloud / Security Command Center over every account; auto-ticket findings above your accepted-risk threshold. #### Configuration Management **Policy-as-code.** Codify the control as Service Control Policies (AWS), Azure Policy initiatives, or Organisation Policy (GCP) so the platform enforces what the document promises. **IaC.** Gate Terraform / Pulumi / CloudFormation changes with Checkov / tfsec / OPA so misconfigurations never reach production. **Drift.** Run a CSPM (Wiz / Prisma / Defender for Cloud / Security Command Center) over every account and route findings to a single risk register. #### Network Security **AWS.** VPC Flow Logs to S3, default-deny security groups, AWS Network Firewall for north-south, and Transit Gateway for hub-and-spoke segmentation. **Azure.** NSGs with deny-by-default, Azure Firewall Premium with TLS inspection, Private Endpoints for PaaS, and Microsoft Defender for Cloud's secure score for drift. **GCP.** VPC Service Controls perimeters around sensitive APIs, Cloud NGFW Enterprise for L7 inspection, Private Service Connect for managed services. ### Operational checklist - **Security.** Document the trigger, the owner and the cadence. - **Physical.** Document the trigger, the owner and the cadence. - **Perimeter.** 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. - **Scope:** measures, protection, - configuration, management. ## Evidence to collect - **Infra Scan.** Continuous infrastructure-posture telemetry — AWS Config, Azure Policy compliance, GCP Organisation Policy, Wiz / Prisma findings. Infrastructure posture tooling (AWS Config, Azure Policy, Nessus) verifies platform hardening. Focus: Perimeter Protection. ## Common pitfalls - Treating CSPM findings as a backlog instead of a hot queue: findings older than the policy SLA accumulate until the auditor asks why. - Manual cloud-console changes that never make it back to Terraform — drift accumulates until the next outage forces a reconciliation. - Default-allow egress rules; East-West traffic with no segmentation; jump hosts on the public internet with password auth. ## 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. - [**NIST SP 800-53 Rev. 5 CP-9(3)** — Separate Storage For Critical Information](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/cp-9-3-separate-storage-for-critical-information) - [**NIST SP 800-171 Rev. 3 3.14.8** — Information Management and Retention](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-14-8-information-management-and-retention) - [**ISO/IEC 27001:2022 A.5.34** — Privacy and protection of personal identifiable information (PII)](https://support.icompaas.com/compliance/iso-27001-2022/a-5-34-privacy-and-protection-of-personal-identifiable-information-pii) - [**CIS Controls v8 4.2** — Establish and Maintain a Secure Configuration Process for Network Infrastructure](https://support.icompaas.com/compliance/cis-controls-v8/4-2-establish-and-maintain-a-secure-configuration-process-for-network-infrastructure) ## Related controls in BSI C5:2020 - [**Criterion PS-05** — Protection against threats from outside and from the environment](https://support.icompaas.com/compliance/bsi-c5-2020/ps-05-protection-against-threats-from-outside-and-from-the-environment) - [**Criterion PS-06** — Protection against interruptions caused by power failures and other such risks](https://support.icompaas.com/compliance/bsi-c5-2020/ps-06-protection-against-interruptions-caused-by-power-failures-and-other-such-risks) - [**Criterion HR-06** — Confidentiality agreements](https://support.icompaas.com/compliance/bsi-c5-2020/hr-06-confidentiality-agreements) - [**Criterion INQ-02** — INQ-02 Informing Cloud Customers about Investigation Requests](https://support.icompaas.com/compliance/bsi-c5-2020/inq-02-inq-02-informing-cloud-customers-about-investigation-requests) - [**Criterion PSS-06** — Session Management](https://support.icompaas.com/compliance/bsi-c5-2020/pss-06-session-management) - [**Criterion COS-05** — Networks for administration](https://support.icompaas.com/compliance/bsi-c5-2020/cos-05-networks-for-administration) ## References - [Bundesamt für Sicherheit in der Informationstechnik (BSI) — BSI C5:2020](https://www.bsi.bund.de/EN/Topics/CloudComputing/Compliance_Criteria_Catalogue/Compliance_Criteria_Catalogue_node.html) - Catalogue identifier: `Criterion PS-03` Topics: physical securitycloud infrastructurecloud postureconfiguration managementnetwork security ## Related compliance guidance - [SOC 2 compliance: a practical implementation guide for cloud-native SaaS teams](https://support.icompaas.com/compliance/soc-2-trust-services-criteria): Configuration checks like this one are the technical half of a SOC 2 / ISO 27001 programme — the guide shows where they fit, what else an auditor expects, and how to evidence them. - [ISO/IEC 27001:2022 compliance: a practical implementation guide](https://support.icompaas.com/compliance/iso-27001-2022): ISO 27001 Annex A.8 (technological controls) is where cloud hardening evidence lands; the guide shows how to run the ISMS around it.