BSI C5:2020 IDM-08 — Confidentiality of authentication information

What this control requires

Ensures password confidentiality through user-created or mandatory initial changes, enforcing IDM-12 specifications and secure storage with strong hash functions. Mitigates risks via analysis, protecting cloud customer data from credential compromise.

In plain English

Ensures password confidentiality through user-created or mandatory initial changes, enforcing IDM-12 specifications and secure storage with strong hash functions. In practice, this means you can prove you information 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 Identity & Access Management, the assessor will trace your implementation back to the catalogue reference (Criterion IDM-08) 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.

Operational checklist

• Information. Document the trigger, the owner and the cadence.
• Review. Document the trigger, the owner and the cadence.
• Confidentiality. 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: protection, cloud customer data, authentication information, changes, management.

Evidence to collect

• Identity Scan. IAM / IdP exports — Entra ID, Okta, IAM Identity Center, Workspace directory — showing accounts, roles, MFA state and last sign-in.

Identity analytics (Okta, SailPoint, Access Analyzer) demonstrates least-privilege. Focus: Confidentiality of authentication information.

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.

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.

• SOC 2 (2017 TSC) P5.1 — Data Subject Access to Personal Information
• NIST SP 800-53 Rev. 5 SC-23 — Session Authenticity
• NIST SP 800-171 Rev. 3 3.13.4 — Information in Shared System Resources
• ISO/IEC 27001:2022 A.5.2 — Information security roles and responsibilities
• GDPR Article 13 — Information to be provided where personal data are collected from the data subject

Related controls in BSI C5:2020

• Criterion PSS-07 — Confidentiality of Authentication Information
• Criterion IDM-03 — Locking and withdrawal of user accounts in the event of inactivity or multiple failed logins
• Criterion IDM-07 — Access to cloud customer data
• Criterion IDM-04 — Withdraw or adjust access rights as the task area changes
• Criterion IDM-05 — Regular review of access rights
• Criterion PSS-09 — Authorisation Mechanisms

References

• Bundesamt für Sicherheit in der Informationstechnik (BSI) — BSI C5:2020
• Catalogue identifier: Criterion IDM-08

Topics: identity accessdata protectionidentity managementaccess reviewprivileged accesscloud posture