# BSI C5 COS-01 — Technical safeguards

- Source: https://support.icompaas.com/support/solutions/articles/a_gen_bsic5_cos01_0a5d9fff25-bsi-c5-cos-01-technical-safeguards
- Section: [Solutions](https://support.icompaas.com/support/solutions) › [BSI C5 (German Cloud)](https://support.icompaas.com/support/solutions/c_gen_bsi_c5) › [Communication & Network Security](https://support.icompaas.com/support/solutions/folders/f_gen_cgenbsic5_communicationnetworksecurity)
- Last updated: 2026-05-30
- Publisher: iCompaas, Inc. (https://www.icompaas.com)

BSI C5 · Control COS-01 · Priority: high · Component: Communication & Network Security

### What this control covers

Implements technical safeguards per OIS-06 risk analysis to detect and respond to network-based attacks, including DDoS, using SIEM systems. Documents measures per SP-01, ensuring prompt mitigation to protect cloud customer data from network threats.

### Why it matters

A defended network limits blast radius after an initial compromise — the difference between an incident and a breach is often the controls described here.

### How to implement

#### AWS

Segment workloads into separate **VPCs/accounts per environment**. Use **security groups** as stateful allow-lists (least-port, source by SG ID not 0.0.0.0/0) and **VPC Flow Logs** to CloudWatch/S3. Front public services with **AWS WAF + Shield Advanced** and use **PrivateLink/VPC Endpoints** to keep service traffic off the internet.

#### Azure

Use **Network Security Groups** and **Application Security Groups** for east-west, and an **Azure Firewall** or NVA in a hub VNet for north-south. Enforce **Private Endpoints** for PaaS and turn on **Defender for Cloud — Network** for adaptive hardening recommendations.

#### GCP

Use **VPC Service Controls** to draw a perimeter around sensitive APIs and a hierarchical **Firewall policy** at the org/folder level so projects inherit a deny-by-default posture. Front HTTP workloads with the global **Cloud Load Balancer + Cloud Armor**.

### Evidence to collect

-   `infra_scan` — See the iCompaas Evidence library for the canonical source for this evidence type.

Infrastructure posture tooling (AWS Config, Azure Policy, Nessus) verifies platform hardening. Focus: Technical safeguards.

### Quick checklist

-   Risk — Measures / - Configuration
-   Security — Measures / - Configuration
-   Data — Measures / - Configuration
-   Technical — Measures / - Configuration

### Related articles on this site

-   [NIST 800-171 3.14.6 Monitor organizational systems, including inbound and outbound communications traffic, to detect attacks and indicators of potential attacks.](https://support.icompaas.com/support/solutions/articles/62000229232-nist-800-171-3-14-6-monitor-organizational-systems-including-inbound-and-outbound-communications-tra)
-   [CMMC 2.0 SI.2.216 Monitor organizational systems, including inbound and outbound communications traffic, to detect attacks and indicators of potential attacks.](https://support.icompaas.com/support/solutions/articles/62000229427-cmmc-2-0-si-2-216-monitor-organizational-systems-including-inbound-and-outbound-communications-traff)
-   [Microsoft Cloud Security Posture Management (CSPM)](https://support.icompaas.com/support/solutions/articles/62000234105-microsoft-cloud-security-posture-management-cspm-)
-   [NIST 800-171 3.4.2 Establish and enforce security configuration settings for information technology products employed in organizational systems.](https://support.icompaas.com/support/solutions/articles/62000229281-nist-800-171-3-4-2-establish-and-enforce-security-configuration-settings-for-information-technology-p)

## 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.