ISO 13485 design and development documentation and IEC 62304 software architecture specification for component structure.
Defense-in-depth architecture with security requirements assigned per layer, safety impact assessment for each security control, and explicit threat-to-control traceability.
Security architecture document with per-layer controls and documented safety impact review — single-perimeter designs without layered internal controls are a major Notified Body non-conformity.
Maps to
IEC 81001-5-1: §5.3.1 DEFENSE-IN-DEPTH ARCHITECTURE/design
Requirement text
The manufacturer shall establish an activity (or activities) to specify a secure architecture. At each stage of development, the manufacturer should consider defense-in-depth and assign technical requirements to each layer of defense. When identifying technical security risk controls, the manufacturer shall take into account requirements regarding safety or performance of health software.
Why this clause exists
Devices designed with a flat security architecture — where all components have equivalent access to all others, and where a single exploited vulnerability can cascade to full system compromise — violate the defense-in-depth principle that the security engineering community has recognized as foundational since the 1990s. Medical devices that concentrated all security in a perimeter control while providing no internal segmentation were compromised by attackers who bypassed or manipulated the perimeter — a predictable outcome that the defense-in-depth requirement directly prevents. IEC 81001-5-1:2021 clause 5.3.1 requires the security architecture to implement multiple independent layers of security controls, so that the failure of any single control does not expose the full attack surface to an adversary. For medical devices, this principle applies across the full system: network boundary controls, host-level controls, application-level controls, and data-level controls should each be designed to limit the blast radius of a breach of any single layer. FDA's premarket cybersecurity guidance explicitly references defense-in-depth as an expected architectural property in cybersecurity documentation.
What changed
IEC 81001-5-1:2021 is the first standalone cybersecurity standard purpose-built for health software and medical device software. Published in December 2021, it was adapted from IEC 62443-4-1 (industrial control systems security) to address the unique safety and regulatory context of medical devices — adding health-specific requirements that account for patient safety, clinical workflows, and the manufacturer-HDO relationship.
The standard mirrors IEC 62304's lifecycle structure but adds security-specific activities at every phase — planning, development, testing, release, and maintenance. It requires security risk management to be integrated with ISO 14971 safety risk management, not treated as a separate IT concern. FDA recognized it as Consensus Standard 13-122 (date of entry December 19, 2022). FDA's February 2026 cybersecurity guidance, Section V, lists IEC 81001-5-1 among the "possible frameworks to consider" for secure product development, and FDA's recognition record for the standard notes that conformance "may not satisfy all the cybersecurity requirements outlined in Section 524B of FD&C Act".
EU MDR harmonization was originally targeted for May 2024 but postponed to May 2028.
Common gaps (what we see in audits)
- Single-layer security controls without defense-in-depth — Manufacturers implement a single security boundary (e.g., authentication at the API gateway) without layered controls at multiple architectural levels. Notified Bodies reject designs that rely solely on a single perimeter defense without internal software item segregation. Defense-in-depth requires controls at network, application, data, and component levels.