boma/docs/security/accepted-risks.md

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# 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 | **Self-hosted mesh control plane is a public target on `askari`** — the NetBird coordinator (ADR-016) exposes a management API + dashboard (TCP 80/443) and STUN (UDP 3478) on `askari`'s public IP; the management API controls the whole mesh (NetBird v0.72.4 embeds STUN in the combined server — no separate Coturn) | Self-hosting means **no third-party trust** and an off-site control plane that survives a homelab outage (boma's sovereignty ethos). Residual surface is on `askari` (already a public VPS) and is mitigated: TLS + embedded-IdP login, source-IP restriction where practical, `base` hardening, version-pinned NetBird (ADR-011) patched on boma's cadence | A coordinator compromise or unpatched NetBird CVE; the management plane is reachable without auth/IP-limits; the operational burden makes a hosted coordinator worth reconsidering |
| R4 | **No cryptographic WORM for logs** — shipped logs are append-only via Loki's push API and copied off-site to `askari` (ADR-018), but the stored chunks are not object-locked/immutable; a root-on-`askari` attacker could edit history | Append-only push + off-site copy already defeats the realistic threat (a host attacker covering tracks survives even full-cluster compromise). True WORM (object-lock) is forensic-grade cost for boma's opportunistic threat model (R1) | Threat model shifts toward targeted/forensic; a regulatory/evidentiary need appears; `askari` itself is assessed as a likely target |
| R5 | **No disk encryption on `ubongo`** — the control node's SSD (SanDisk X600 256 GB, TCG-Opal-capable but Opal unused) is unencrypted at rest, so it holds recovery-critical secrets in plaintext: the Ansible Vault password's `rbw` local cache and (future) Terraform state. Physical theft of the box would expose them | `ubongo` is always-on in a physically controlled location; compensating controls are a **BIOS supervisor password** and **disabled external/USB + PXE boot** (an attacker cannot trivially boot another OS to read the disk), and the offline-recoverable design means the irreducible root secret (Vaultwarden master password) is never stored on the box anyway. Full-disk encryption was weighed against the always-on/unattended-reboot requirement (LUKS+TPM auto-unlock or passphrase) and deferred for simplicity at this trust level | `ubongo` is relocated to a less-trusted physical location; the box starts holding additional high-value secrets; or a reinstall onto LUKS (TPM-sealed) is undertaken |
| R6 | **`le-prod-wildcard` integration runs** — when `CERTS=le-prod-wildcard` is passed to `make test-integration`, the production Gandi PAT (`vault.gandi.pat`) is passed to an ephemeral local test VM via the var overlay, and transient `_acme-challenge` TXT records are written into the real `wingu.me` DNS zone to satisfy the Let's Encrypt DNS-01 challenge. A compromised or long-lived test VM could exfiltrate the PAT; the real zone is briefly (seconds) modified | Scope is **on-demand only**`le-staging` is the default cert tier (`CERTS=internal` for incident repro); `le-prod-wildcard` is an explicit opt-in. Compensating controls: the VM is ephemeral and destroyed on success; it sits on an isolated libvirt NAT network (no LAN/mesh access); TXT records are auto-removed by Caddy immediately after validation; the PAT is not persisted inside the VM after the run. ADR-025 documents the cert-tier design and the three isolation invariants | The PAT is exfiltrated from a test VM; the `wingu.me` zone shows unexpected records; a `CERTS=le-prod-wildcard` run must be audited or the tier must be revoked |
_Last reviewed: 2026-06-11. 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._