PCI DSS 3.5.1.2: Separate Disk Encryption from OS Authentication
Disk-level encryption protects sensitive data at rest, but only when access controls operate independently of your operating system. PCI DSS 3.5.1.2 requires that logical access to encrypted disks be managed separately from OS authentication mechanisms. This critical separation prevents unauthorized access even if OS credentials are compromised.
What this means
When you implement disk or partition-level encryption, you must ensure that access to encrypted data is controlled by a system independent of your OS login credentials. This means encryption key management, decryption authorization, and logical access controls should function separately from Windows, Linux, or macOS authentication. The goal is creating a dual-control requirement where compromising one authentication system doesn't automatically grant access to encrypted partitions.
How to comply
- 1.Implement disk encryption tools (BitLocker, FileVault, LUKS) with separate credential management from OS accounts
- 2.Configure encryption key storage on separate hardware security modules (HSMs) or key management systems (KMS)
- 3.Establish independent access controls requiring additional authentication beyond OS login to decrypt or access encrypted volumes
- 4.Document encryption architecture showing clear separation between OS authentication and encryption key access
- 5.Implement monitoring and logging for all decryption events and key access attempts
- 6.Test failover scenarios to confirm encryption access persists even if OS authentication is compromised
- 7.Apply MFA to encryption key management systems independently from OS MFA requirements
Evidence auditors look for
- HSM configuration logs showing encryption keys stored separately from OS credential stores
- Key management system audit trails documenting independent access authentication events
- Network diagrams illustrating encryption key server separation from domain controllers
- BitLocker/FileVault configuration exports showing startup PIN or separate credential requirements
- Access control matrix proving dual-factor authentication for encrypted partition access
- Penetration test results confirming OS credential compromise does not decrypt partitions
- Change logs documenting encryption key rotation managed outside OS user management systems
Frequently asked questions
When will FAQs be available?
The FAQ for this control is currently being prepared.
GRCWatch automatically maps your encryption configuration to PCI DSS requirements, verifies separation between OS and encryption controls, and generates audit-ready evidence reports for 3.5.1.2 validation.
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