# Defense in Depth

> A design rule that several independent security controls protect each asset, so one failed control does not expose it.

Record: `architecture:defense-in-depth`
Kind: principle
Layer: [Security Core](https://banes-lab.com/records/layer/security-core.md)
Severity: mandatory
Scope: system, infrastructure, application
Canonical: https://banes-lab.com/ontology#architecture-defense-in-depth

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Security by Design](https://banes-lab.com/records/architecture/security-by-design.md) and before [Least Privilege](https://banes-lab.com/records/architecture/least-privilege.md).

## Repair

- Refactored by: Add Layered Controls
- Detected by: missing secondary control
- Violated by: relying on only one security layer
- Measured by: control depth
- Enforced by: threat model review

## Requires

- [Layered Controls](https://banes-lab.com/records/lexicon/layered-controls.md)

## Reinforces

- [Security by Design](https://banes-lab.com/records/architecture/security-by-design.md)

## Enables

- [Compromise Containment](https://banes-lab.com/records/lexicon/compromise-containment.md)

## Conflicts with

- [Single Control Reliance](https://banes-lab.com/records/lexicon/single-control-reliance.md)

## In tension with

- [Complexity](https://banes-lab.com/records/lexicon/complexity.md)

## Tensions

- [Defense in Depth / Complexity](https://banes-lab.com/records/tension/complexity-defense-in-depth.md)

## Severity

- [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md)

## Category

- [Security / Privacy / Compliance / Governance](https://banes-lab.com/records/architecture-category/security-privacy-compliance-governance.md)

## Reinforced by

- [CSRF Protection](https://banes-lab.com/records/architecture/csrf-protection.md)

## Linked from

- [Security / Privacy / Compliance / Governance](https://banes-lab.com/ontology/principles/architecture-category-security-privacy-compliance-governance.md)
- [Quality Attributes](https://banes-lab.com/ontology/lexicon/lexicon-category-quality-attributes.md)
- [Security Privacy Compliance](https://banes-lab.com/ontology/lexicon/lexicon-category-security-privacy-compliance.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The resolutions](https://banes-lab.com/ontology/schema/the-resolutions.md)