boma/docs/security/accepted-risks.md

# Accepted security risks

Conscious security trade-offs we are choosing to live with — recorded so "what we
are *not* doing" is explicit and revisitable, not forgotten. This register is a
**living document**, deliberately kept out of ADR-002 (which records durable
decisions) so the ADR stays stable.

Owned by **ADR-002** (Security baseline and strategy). Re-challenged during the
periodic security review (planned `/security-review`; see `docs/TODO.md`).

**Each entry:** the risk · why we accept it (rationale) · what would make us
revisit (trigger).

| # | Accepted risk | Rationale | Revisit trigger |
|---|---|---|---|
| R1 | **Active supply-chain scanning deferred** — baseline hygiene *is* required (tiered image pinning per ADR-011 — stateful `tag@digest`, stateless rolling — prefer official/verified images; gitleaks), but images and dependencies are not actively vulnerability-scanned (Trivy/Grype) or signature-verified | Scanning only pays off with the capacity to triage its output; the realistic threat is opportunistic, not a targeted supply-chain attack | A monitoring/triage stack is live; hosting high-value data/finances for others; a relevant upstream compromise |
| R2 | **SELinux not used** — no SELinux mandatory access control | AppArmor — Debian-native and enforced via the CIS baseline — already provides MAC; adding SELinux means two MAC systems, non-native to Debian, for no real gain | A service that ships and requires its own SELinux policy; threat model shifts toward targeted attackers |
| R3 | **Mesh-VPN coordinator dependency (pending VPN choice)** — remote SSH to the control node `ubongo` (ADR-015) rides a mesh VPN whose coordination plane may be a third party (e.g. hosted Tailscale/NetBird) | A hosted coordinator keeps the mesh up when the cluster is down, which *helps* recovery; nothing is exposed to the public internet (ADR-002 preserved). Provisional — finalised when the VPN is chosen (separate discussion) | The VPN choice is settled (replace this entry with the concrete decision); a self-hosted coordinator is adopted; the provider's trust/security posture changes |

_Last reviewed: 2026-06-05. The prior gaps (full CIS hardening, SELinux/AppArmor,
IDS) were re-challenged and **adopted rather than accepted**: CIS Debian L1+L2 + CIS
Docker, AppArmor (enforce), AIDE file-integrity, and Suricata network IDS are now
part of the security strategy (ADR-002). See STATUS.md / `docs/TODO.md` for build
status. As CIS is implemented, any specific item that proves impractical is added
here as a named exception._