541 lines
9.7 KiB
Groff
541 lines
9.7 KiB
Groff
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PrivilegedExecutionControlStandard
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*Maturity model to minimize privileged attack surfaces*
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# Privileged Execution Control Standard (PECS)
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### A maturity model and reference framework for controlling privileged execution in software systems
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**Version:** 0.2 (Draft)
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**Status:** Candidate Architecture Standard
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**Authoring Context:** DevSecOps / Platform Engineering / Secure Automation
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**Audience:**
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* Software architects
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* DevOps engineers
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* Security engineers
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* CI/CD maintainers
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* AI coding agents operating within repositories
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---
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# 1. Purpose
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The **Privileged Execution Control Standard (PECS)** defines a structured approach to controlling **privileged operations** in software systems.
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It provides:
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1. **Terminology and conceptual model**
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2. **A multidimensional maturity assessment**
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3. **Design patterns for privilege boundaries**
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4. **Implementation guidance for common environments**
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5. **Mapping to existing security frameworks**
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The goal is to ensure that systems:
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* minimize privileged attack surfaces
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* provide deterministic authorization of privileged operations
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* enable secure automation
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* remain auditable and maintainable
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---
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# 2. Scope
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PECS applies to **software systems that contain privileged operations**, including:
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* DevOps pipelines
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* build systems
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* operational tooling
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* infrastructure automation
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* platform management systems
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* cluster orchestration
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Privileged execution environments include:
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* OS-level root privileges
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* container runtime privileges
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* Kubernetes cluster permissions
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* administrative API credentials
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* infrastructure automation roles
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---
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# 3. Core Security Principles
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PECS builds on established security principles.
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## 3.1 Least Privilege
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Privileged permissions must be limited to **the smallest possible scope**.
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---
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## 3.2 Explicit Privilege Boundaries
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All privileged execution must occur through **clearly defined entry points**.
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---
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## 3.3 Deterministic Authorization
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Privilege elevation must rely on **explicit authorization mechanisms**, not implicit behavior.
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---
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## 3.4 Integrity Binding
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Authorization must bind to **specific executable artifacts**.
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---
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## 3.5 Auditability
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The system must provide verifiable answers to:
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* What privileged operations exist?
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* Who approved them?
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* What code was approved?
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* What executed?
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---
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# 4. Conceptual Model
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The PECS conceptual model is **implementation independent**.
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## 4.1 Privileged Execution
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An operation requiring elevated authority beyond the normal execution context.
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Examples:
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* root access
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* administrative API access
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* cluster-level operations
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* privileged containers
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---
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## 4.2 Privileged Entry Point (PEP)
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A programmatic interface that performs privileged actions.
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Examples:
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```
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backup-root
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rootctl snapshot
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kubectl apply (cluster-admin)
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```
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---
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## 4.3 Privileged Invocation
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The act of executing a privileged entry point.
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---
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## 4.4 Privileged Execution Surface (PES)
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The set of all privileged entry points in a system.
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---
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## 4.5 Privileged Authorization Artifact (PAA)
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A machine-readable document defining which privileged operations are approved.
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---
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## 4.6 Integrity Binding
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A mechanism that links approval to a **specific artifact version**.
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Examples:
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* SHA256 digest
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* signed binary
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* provenance metadata
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---
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## 4.7 Privileged Execution Gateway (PEG)
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A centralized system responsible for executing privileged actions.
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Example:
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```
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rootctl
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```
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---
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# 5. Multidimensional Maturity Model
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PECS maturity is evaluated along **five independent dimensions**.
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| Dimension | Description |
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| ------------------------ | ----------------------------- |
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| Privilege Boundary | isolation of privileged logic |
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| Authorization Governance | approval workflow |
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| Integrity Assurance | binding approvals to code |
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| Execution Enforcement | runtime enforcement |
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| Auditability | execution tracking |
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---
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# 6. Maturity Levels
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Each dimension has maturity levels from **0–5**.
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---
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# 6.1 Dimension 1 — Privilege Boundary Isolation
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| Level | Description |
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| ----- | --------------------------------- |
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| 0 | privilege used anywhere |
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| 1 | privilege isolated in scripts |
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| 2 | dedicated privileged entry points |
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| 3 | centralized gateway |
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| 4 | restricted execution environment |
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| 5 | formally defined privileged API |
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---
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# 6.2 Dimension 2 — Authorization Governance
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| Level | Description |
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| ----- | --------------------------------- |
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| 0 | no approval process |
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| 1 | manual review |
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| 2 | documented allowlist |
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| 3 | fingerprint approval |
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| 4 | signed approvals |
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| 5 | policy-based automated governance |
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---
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# 6.3 Dimension 3 — Integrity Assurance
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| Level | Description |
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| ----- | ------------------------- |
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| 0 | no verification |
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| 1 | manual checks |
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| 2 | checksums |
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| 3 | hash verification |
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| 4 | signed artifacts |
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| 5 | supply chain attestations |
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---
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# 6.4 Dimension 4 — Execution Enforcement
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| Level | Description |
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| ----- | ------------------------------ |
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| 0 | uncontrolled privilege use |
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| 1 | wrapper enforcement |
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| 2 | tool-level restrictions |
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| 3 | platform enforcement |
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| 4 | policy engines |
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| 5 | zero-trust privilege mediation |
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---
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# 6.5 Dimension 5 — Auditability
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| Level | Description |
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| ----- | -------------------------- |
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| 0 | no logging |
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| 1 | local logs |
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| 2 | structured logs |
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| 3 | centralized logging |
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| 4 | tamper-resistant logs |
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| 5 | cryptographic audit trails |
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---
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# 7. Example Maturity Assessment
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Example system:
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| Dimension | Level |
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| ------------ | ----- |
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| Boundary | 2 |
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| Governance | 2 |
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| Integrity | 3 |
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| Enforcement | 2 |
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| Auditability | 1 |
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Result:
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```
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PECS maturity profile:
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(2,2,3,2,1)
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```
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This allows targeted improvements.
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---
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# 8. Reference Authorization Artifact
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Example YAML:
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```yaml
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version: 1
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privileged_commands:
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- id: backup
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entrypoint: scripts/backup-root
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sha256: 3d9c9c21d0c82a4c9f
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reviewer: security-team
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approved: 2026-03-10
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- id: snapshot
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entrypoint: scripts/snapshot-root
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sha256: 7e2f15b1c93b
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```
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---
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# 9. Privileged Invocation Contract
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Every PEP should define:
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* command identity
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* allowed arguments
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* execution context
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* expected effects
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Example:
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```
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rootctl snapshot
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arguments:
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volume: string
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allowed-callers:
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CI-backup
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```
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---
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# 10. Implementation Guides
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The following chapters map PECS to practical environments.
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---
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# 11. Implementation Guide — Linux / sudo
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## Design Pattern
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```
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make backup
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prepare.sh
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sudo rootctl backup
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```
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---
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## Example root entrypoint
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```bash
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#!/usr/bin/env bash
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set -euo pipefail
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if [[ "$EUID" -ne 0 ]]; then
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echo "ERROR: must run as root"
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exit 1
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fi
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case "$1" in
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backup)
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./backup-logic.sh
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;;
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*)
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echo "unknown command"
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exit 1
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esac
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```
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---
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## sudoers example
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```
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ci-runner ALL=(root) NOPASSWD: /usr/local/bin/rootctl
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```
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---
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## Hash validation example
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```
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sha256sum rootctl
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```
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---
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|||
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# 12. Implementation Guide — Kubernetes / RBAC
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|||
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|||
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Privilege boundaries map to **cluster roles**.
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|||
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|||
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Example:
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|||
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|||
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```
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ClusterRole: backup-controller
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```
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|||
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---
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|||
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|||
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Example policy:
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```
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apiGroups:
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- ""
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resources:
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- persistentvolumes
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verbs:
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- get
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- list
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|||
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```
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|||
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|||
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---
|
|||
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|||
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Privileged gateway concept becomes:
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|||
|
|
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|||
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```
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|||
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controller operator
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|||
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```
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|||
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|||
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---
|
|||
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|||
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# 13. Implementation Guide — CI/CD Pipelines
|
|||
|
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|
|||
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Example:
|
|||
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|
|||
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```
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|||
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pipeline
|
|||
|
|
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|||
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build
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|||
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|
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|||
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privileged step
|
|||
|
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|||
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deploy
|
|||
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```
|
|||
|
|
|
|||
|
|
Privileged step invokes **approved gateway**.
|
|||
|
|
|
|||
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|
---
|
|||
|
|
|
|||
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Example GitHub Action:
|
|||
|
|
|
|||
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|
```
|
|||
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sudo rootctl deploy
|
|||
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```
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|||
|
|
|
|||
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|
---
|
|||
|
|
|
|||
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|
Policy checks verify:
|
|||
|
|
|
|||
|
|
* artifact fingerprint
|
|||
|
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* approval metadata
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
# 14. Assessment Procedure
|
|||
|
|
|
|||
|
|
Assess a system using:
|
|||
|
|
|
|||
|
|
1. Identify privileged operations
|
|||
|
|
2. Map entry points
|
|||
|
|
3. Evaluate each maturity dimension
|
|||
|
|
4. Produce maturity profile
|
|||
|
|
5. Identify gaps
|
|||
|
|
6. generate improvement roadmap
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
# 15. Regulatory Mapping
|
|||
|
|
|
|||
|
|
PECS aligns with:
|
|||
|
|
|
|||
|
|
| Standard | Relevant Controls |
|
|||
|
|
| --------------- | ---------------------- |
|
|||
|
|
| NIST 800-53 | AC-6, CM-3, SI-7 |
|
|||
|
|
| NIST Zero Trust | policy enforcement |
|
|||
|
|
| OWASP CI/CD | least privilege |
|
|||
|
|
| CIS Controls | privilege management |
|
|||
|
|
| SLSA | supply chain integrity |
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
# 16. Enterprise Tooling Mapping
|
|||
|
|
|
|||
|
|
Common enterprise tools implementing similar concepts.
|
|||
|
|
|
|||
|
|
| Category | Examples |
|
|||
|
|
| -------------- | --------------------- |
|
|||
|
|
| PAM systems | CyberArk, BeyondTrust |
|
|||
|
|
| Policy engines | OPA |
|
|||
|
|
| CI/CD security | GitHub OIDC policies |
|
|||
|
|
| Audit logging | Splunk |
|
|||
|
|
|
|||
|
|
PECS can integrate with these.
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
# 17. Appendix — Terminology
|
|||
|
|
|
|||
|
|
PEP — Privileged Entry Point
|
|||
|
|
PES — Privileged Execution Surface
|
|||
|
|
PAA — Privileged Authorization Artifact
|
|||
|
|
PEG — Privileged Execution Gateway
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
# 18. Appendix — Relationship to Existing Patterns
|
|||
|
|
|
|||
|
|
Similar concepts exist in:
|
|||
|
|
|
|||
|
|
* sudo command restrictions
|
|||
|
|
* Microsoft JEA
|
|||
|
|
* Kubernetes RBAC
|
|||
|
|
* in-toto supply chain controls
|
|||
|
|
|
|||
|
|
PECS unifies these into **one architectural model**.
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
# 19. Future Extensions
|
|||
|
|
|
|||
|
|
Potential additions:
|
|||
|
|
|
|||
|
|
* signed execution policies
|
|||
|
|
* hardware root of trust
|
|||
|
|
* runtime policy agents
|
|||
|
|
* AI-assisted security review
|
|||
|
|
|
|||
|
|
---
|
|||
|
|
|
|||
|
|
# Summary
|
|||
|
|
|
|||
|
|
This refined standard provides:
|
|||
|
|
|
|||
|
|
✔ stable abstract model
|
|||
|
|
✔ multidimensional maturity framework
|
|||
|
|
✔ practical implementation guides
|
|||
|
|
✔ regulatory mapping
|
|||
|
|
✔ extensibility across environments
|
|||
|
|
|
|||
|
|
|
|||
|
|
xxx
|