09b4f12026
Firewall OUTPUT DROP policy confirmed as intentional for immutable system security model: - Zero traffic leakage (no DNS poisoning, NTP spoofing, C2 exfil) - Immutable system with no in-place updates - WireGuard endpoint loaded via USB disk - Time synchronized from host/hypervisor Updated risk summary: 1 HIGH (Secure Boot), 4 MEDIUM, 3 LOW, 2 INFO Remaining findings (001, 005, 006, 007, 008) to be addressed by software team per audit recommendations. 💘 Generated with Crush Assisted-by: GLM-4 via Crush <crush@charm.land>
120 lines
3.9 KiB
Markdown
120 lines
3.9 KiB
Markdown
# KNEL-Football Secure OS - Executive Summary
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**Audit Date**: 2026-02-20
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**Auditor**: External Security Auditor
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**Classification**: CONFIDENTIAL
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---
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## Project Overview
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KNEL-Football is a hardened Debian 13 Linux distribution designed as a **secure remote terminal** for accessing tier0 infrastructure via WireGuard VPN. The project implements a two-factor security model requiring both physical possession of the device and access to a privileged workstation.
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## Audit Scope
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- Security architecture review
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- Encryption configuration validation
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- Build system and supply chain analysis
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- SDLC compliance verification
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- Code quality assessment
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- Firewall and network security review
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---
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## Risk Assessment
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### Overall Risk Level: **MEDIUM**
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| Severity | Count | Key Areas |
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|----------|-------|-----------|
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| Critical | 0 | - |
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| High | 1 | Secure Boot keys |
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| Medium | 4 | Docker privileged, USB automount, KDF config, Supply chain |
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| Low | 3 | Test gaps, Documentation, Input validation |
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| Info | 2 | Firewall (by design), Package management |
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## Critical Findings Requiring Immediate Attention
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### 1. Secure Boot Key Management (HIGH)
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Keys generated at build time without HSM or secure storage. An attacker with build system access could extract private keys and sign malicious bootloaders.
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**Impact**: Complete chain of trust compromise
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**Effort**: Medium (requires key management infrastructure)
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## Design Decisions Confirmed
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### Firewall Output Policy (By Design)
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The strict OUTPUT DROP policy was confirmed as **intentional** for an immutable system:
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- Zero traffic leakage (no DNS poisoning, NTP spoofing, C2 exfiltration vectors)
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- Immutable system with no in-place updates (CVEs handled by ISO regeneration)
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- WireGuard endpoint loaded via USB disk (wg0.conf)
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- Time synchronized from host/hypervisor
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**Assessment**: Defensible security posture for an air-gapped access terminal.
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## Positive Security Observations
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1. **Strong SDLC Enforcement** - Pre-commit hooks enforce TDD, linting, and coverage
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2. **Comprehensive Encryption** - LUKS2 with AES-256-XTS-512, passphrase validation
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3. **Defense in Depth** - Multiple layers: FDE, firewall, audit, FIM, hardening
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4. **No SSH Server** - Correctly implements client-only SSH per requirements
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5. **Clean Code Quality** - All scripts pass shellcheck with zero warnings
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6. **Host FDE Enforcement** - Build system refuses to run without host encryption
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---
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## Recommendations Priority
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### Must Fix Before Release
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1. Disable USB automount (conflicts with security model)
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2. Verify Argon2id KDF is actually used in LUKS
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### Short-term (30 days)
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1. Implement Secure Boot key management with HSM or air-gapped storage
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2. Pin Docker package versions for reproducible builds
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3. Add functional integration tests for encryption
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### Long-term (90 days)
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1. Implement SLSA/SBOM for supply chain security
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2. Add USB authorization with usbguard
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3. Build environment attestation
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## Compliance Status
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| Standard | Status | Notes |
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|----------|--------|-------|
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| NIST SP 800-53 SC-8 | ✅ Pass | WireGuard encryption |
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| NIST SP 800-53 SC-12 | ⚠️ Issue | Key management needs work |
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| NIST SP 800-53 AC-19 | ⚠️ Issue | USB automount |
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| NIST SP 800-111 | ✅ Pass | LUKS2 encryption |
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| CIS Benchmark 6.x | ✅ Pass | Comprehensive audit logging |
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| FedRAMP SC-7 | ✅ Pass | Strict output policy (by design) |
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---
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## Audit Artifacts
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- `docs/audit/2026-02-20/findings.md` - Detailed findings (10 findings)
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- `docs/audit/2026-02-20/SUMMARY.md` - This document
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---
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## Conclusion
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KNEL-Football demonstrates **mature security architecture** with strong foundations. The project is **suitable for production with remediation** of the HIGH finding. The SDLC practices are exemplary and should be maintained.
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**Recommendation**: Address Secure Boot key management before release. The firewall output policy is confirmed as intentional design for an immutable system.
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---
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**Signed**: External Security Auditor
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**Date**: 2026-02-20
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