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Fixed the secure boot enrollment script

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Audiobuzz
2026-06-20 12:16:37 +00:00
parent 33583bb4d8
commit d2b2156a22
7 changed files with 194 additions and 45 deletions
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docs/ssp-annex-a-ism-residual-risk.md
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@@ -8,6 +8,11 @@
>
> **A&A framework:** ASD *Information Security Manual* (ISM) — engagement target
> **May 2026 release**.
>
> **Annex version:** 0.2 (2026-06-20). v0.2 reflects: STIG hardening applied +
> bench-verified, USBGuard device control enabled, admin `staff_u` confinement,
> audit offload verified, UKI signing wired (not yet enforced — new R-13),
> PXE/iPXE boot path added.
---
@@ -74,8 +79,9 @@ ISM/PSPF style). Ratings are **pre-treatment** unless stated; the AO accepts the
| Topic | ISM (rep.) | Requirement intent | System implementation | Status | Residual |
|---|---|---|---|---|---|
| Hardened OS to ASD/vendor guidance | ISM-1407*, ISM-1408* | Apply a recognised hardening baseline. | **DISA STIG** (SSG `profile_stig`, RHEL 9) via `oscap --remediate` with documented tailoring ([stig-deviations.md](stig-deviations.md)). | Partial | R-03 (CI report-only/disabled now) |
| Application control / allow-listing | ISM-0843*, ISM-1490*, ISM-1657* | Only approved executables run. | **fapolicyd** (RPM-trust + one trusted kiosk binary) + immutable dm-verity root. | Implemented | — |
| Hardened OS to ASD/vendor guidance | ISM-1407*, ISM-1408* | Apply a recognised hardening baseline. | **DISA STIG** (SSG `profile_stig`, RHEL 9) via `oscap --remediate` + documented tailoring + per-build deviations report ([stig-deviations.md](stig-deviations.md)); **applied + bench-verified 2026-06-20**, all REVIEW rows triaged. | Partial | R-03 (CI must ship `enable_stig=true` + signed/SB-on) |
| Application control / allow-listing | ISM-0843*, ISM-1490*, ISM-1657* | Only approved executables run. | **fapolicyd** (RPM-trust + two trusted local binaries: kiosk-session, fleet-sb-enroll) + immutable dm-verity root. | Implemented | — |
| Device / removable-media control | ISM-0341*, ISM-1551* | Control USB / peripheral devices. | **USBGuard enforcing** (`ImplicitPolicyTarget=block` + hardware-independent HID/hub allowlist + LinuxAudit). Verified: USB mass storage blocked, console input preserved. | Implemented | — |
| Software / OS integrity | ISM-1493* | Detect unauthorised modification. | **dm-verity** continuous block-level verification of the read-only root against a signed hash; **reproducible** build. | Implemented | — |
| Disable unneeded functionality | ISM-0380*, ISM-1416* | Minimise installed software/services. | `@^minimal` install; scanner tooling removed post-scan; FROM-scratch artifact image; kiosk = single app. | Implemented | — |
| Hardened user applications (browser) | ISM-1486*, ISM-1412* | Lock down high-risk apps. | Chromium enterprise lockdown policy; weston kiosk; no shell/nav/plugins. | Implemented | — |
@@ -89,7 +95,7 @@ ISM/PSPF style). Ratings are **pre-treatment** unless stated; the AO accepts the
| Topic | ISM (rep.) | Requirement intent | System implementation | Status | Residual |
|---|---|---|---|---|---|
| Strong machine authentication | ISM-1546*, ISM-0974* | Mutual, certificate-based auth. | **802.1X EAP-TLS**, client key non-exportable in **TPM** (`0x81010001`), cert in TPM NV. | Partial | R-01 (not bench-verified; disabled in test builds), R-08 (placeholder CA) |
| Privileged access restricted | ISM-1507*, ISM-0445* | Limit & control admin access. | Single key-only `wheel` admin; root login disabled. | Partial | R-05 |
| Privileged access restricted | ISM-1507*, ISM-0445* | Limit & control admin access. | Single key-only `wheel` admin; root login disabled; admin **confined to `staff_u`** with a sudo `sysadm_r`/`sysadm_t` role/type transition (SELinux context elevates on privilege use). | Partial | R-05 |
| Secure remote administration | ISM-1506*, ISM-1232* | Hardened admin channel. | SSH **key-only**, password & keyboard-interactive off, hardened ciphers/MACs/KEX (STIG crypto policy; ECDSA/RSA keys — ed25519 excluded by policy). | Implemented | — |
| No default/shared credentials | ISM-1304* | No baked credentials. | No per-host secrets in any artifact; identity from TPM at runtime; `machine-id` empty; host keys regenerated at first boot. | Implemented | — |
| MFA for privileged users | ISM-1173*, ISM-1504* | MFA on privileged access. | Machine auth is cert+TPM (strong). **Human admin MFA on the management plane not yet enforced.** | Partial | R-05 |
@@ -109,7 +115,7 @@ ISM/PSPF style). Ratings are **pre-treatment** unless stated; the AO accepts the
| Topic | ISM (rep.) | Requirement intent | System implementation | Status | Residual |
|---|---|---|---|---|---|
| Centralised event logging | ISM-0988*, ISM-1405* | Logs centrally collected. | `audisp-syslog`→rsyslog `omfwd` (disk-assisted queue) → dedicated collector (`serving/audit-collector/`). | Partial | R-07 |
| Centralised event logging | ISM-0988*, ISM-1405* | Logs centrally collected. | `audisp-syslog`→rsyslog `omfwd` (disk-assisted queue) → dedicated collector (`serving/audit-collector/`); **bench-verified end-to-end 2026-06-20**. auditd `space_left_action`→syslog (no MTA). | Partial | R-07 |
| Required events logged | ISM-0582*, ISM-1537* | Log security-relevant events. | STIG auditd rule set; kernel `audit=1`, `audit_backlog_limit=8192`. | Implemented | — |
| Protect logs in transit | ISM-1432*, ISM-0407* | Encrypt/authenticate log transport. | **Plaintext** offload on isolated LAN (rsyslog TLS rules waived — see [STIG #6](stig-deviations.md)). | Waived (lab) | **R-07** |
| Log retention & integrity | ISM-0859*, ISM-1815* | Retain & protect logs. | Per-source-host files on collector; retention policy & tamper-protection not yet defined. | Planned | R-07 |
@@ -144,7 +150,7 @@ ISM/PSPF style). Ratings are **pre-treatment** unless stated; the AO accepts the
| Topic | ISM (rep.) | Requirement intent | System implementation | Status | Residual |
|---|---|---|---|---|---|
| Media sanitisation / no data remanence | ISM-0347*, ISM-1218* | Prevent data remanence. | **Diskless** — no persistent local media; writable layer is **RAM tmpfs**, gone at power-off. | Implemented | — |
| Tamper-evidence / boot integrity | ISM-1542*, ISM-0312* | Detect firmware/boot tampering. | **UEFI Secure Boot** + signed UKI + immutable signed cmdline + dm-verity; TPM measurements available for attestation. | Partial | R-11 (remote attestation not yet implemented) |
| Tamper-evidence / boot integrity | ISM-1542*, ISM-0312* | Detect firmware/boot tampering. | Design: **UEFI Secure Boot** + signed UKI (+ signed iPXE on the PXE path) + immutable signed cmdline + dm-verity; TPM measurements available. Signing **wired in CI** + key/enrolment procedure + baked `fleet-sb-enroll` helper, but **lab runs unsigned with SB OFF**. | Partial | **R-13** (signing not enforced), R-11 (no remote attestation) |
| Device identification | ISM-1195* | Uniquely identify devices. | Identity derived from TPM cert (hostnqn from cert serial); no spoofable per-host config. | Implemented | — |
### 2.11 Guidelines for Procurement, Outsourcing & Evaluated Products
@@ -165,11 +171,12 @@ asked to accept. Treatments map to [docs/TODO.md](TODO.md) (working POA&M).
|---|---|---|---|---|---|---|---|
| **R-01** | Secure path (802.1X EAP-TLS + MACsec) **implemented but not bench-verified end-to-end**; disabled in test builds (`disable_dot1x=true`). Until verified, devices may attach to an unauthenticated/unencrypted link. | 2.4, 2.7, 2.8 (ISM-1546*, 0520*, 1187*) | Likely × Major → **High** | Test path on an isolated lab LAN; full auth stack present (dormant); design follows ASD intent. | Full boot-chain bench test (swtpm + hostapd + FreeRADIUS): port `Authorized`, macsec0 addressed, MKA survives switch-root, NVMe root mounts. Re-enable in CI. | **Low** (once verified) | Platform team — *before production ATO* |
| **R-02** | `debug_shell=true` bakes a **passwordless root shell** on a tty — an undocumented privileged access path. | 2.5 (ISM-1491*) | Possible × Severe → **High** | Lab-only; physical access required; isolated environment. | Set `debug_shell=false` for all non-lab builds; assert absent in CI. | **Low** | Platform team — *before production* |
| **R-03** | STIG hardening currently **report-only / disabled in CI** (`enable_stig=false`); shipped images may be unhardened. | 2.3 (ISM-1407*/1408*) | Possible × Major → **Medium** | Tailoring + register exist; SELinux/fapolicyd still on; re-enable is a single flag. | Flip `ENABLE_STIG="true"`; confirm scan evaluates >0 rules; triage REVIEW rows (buckets A/B/C in TODO #2). | **Low** | Platform team — *before assessment* |
| **R-03** | STIG hardening **applied + bench-verified** (2026-06-20, all REVIEW rows triaged); residual is ensuring **CI ships `enable_stig=true`** for production builds (it was toggled off during bring-up). | 2.3 (ISM-1407*/1408*) | Possible × Moderate → **Medium** | Tailoring + register + per-build report; SELinux/fapolicyd/USBGuard on; verified on a real hardened build. | Confirm `ENABLE_STIG="true"` in CI; keep the 0-eval guard; re-run the deviations report on the assessed build. | **Low** | Platform team — *before assessment* |
| **R-04** | NVMe/TCP **root traffic plaintext** on the LAN — exposure of OS content / injection if the segment is compromised. | 2.9 (ISM-1139*/1453*) | Unlikely × Major → **Medium** | Isolated boot LAN; MACsec on the access link (once R-01 done) protects the first hop; dm-verity makes injected root blocks fail verification (integrity preserved even if confidentiality isn't). | Production: TLS/IPsec for the storage transport, or rely on MACsec end-to-end across the fabric; document the decision. | **Low–Medium** | Platform/network — *production* |
| **R-05** | **NOPASSWD key-only admin**; no per-host or rotatable access model; human admin MFA on the mgmt plane not enforced. | 2.4 (ISM-1507*/1173*) | Possible × Moderate → **Medium** | Single fleet-generic admin, key-only, root disabled, ECDSA/RSA key, fully audited; no interactive password to attack. | Per-host/rotatable access (SSH CA / config-agent) + admin MFA on the management plane. | **Low–Medium** | Platform team — *roadmap* |
| **R-05** | **NOPASSWD key-only admin**; no per-host or rotatable access model; human admin MFA on the mgmt plane not enforced. | 2.4 (ISM-1507*/1173*) | Possible × Moderate → **Medium** | Single fleet-generic admin, key-only, root disabled, ECDSA/RSA key, **now SELinux-confined to `staff_u`** with sudo role/type elevation, fully audited; no interactive password to attack. | Per-host/rotatable access (SSH CA / config-agent) + admin MFA on the management plane. | **Low–Medium** | Platform team — *roadmap* |
| **R-06** | **FIPS off**; ISM **AACA/AACP conformance not formally asserted**; crypto-module evaluation status unconfirmed. | 2.9 (ISM-0471*/1139*/1277*) | Possible × Major → **Medium** | Modern STIG crypto policy; non-exportable TPM key; no deliberately weak algorithms. Acceptable at OFFICIAL; **mandatory to resolve for PROTECTED+.** | Assert AACA/AACP conformance; decide on FIPS module / evaluated crypto alongside Secure Boot signing. | **Low** (at appropriate classification) | Security + Platform — *before PROTECTED+* |
| **R-07** | Audit-log **offload plaintext**, **single-site**, **no SIEM alerting**; logs interceptable/repudiable and not actively reviewed. | 2.6 (ISM-1432*/0109*/0859*) | Possible × Moderate → **Medium** | Isolated LAN; disk-assisted queue (no loss on collector blip); auditd local copy; per-source files. | rsyslog **TLS** (gtls/6514) + bundle CA in image (re-select the 3 waived `rsyslog_encrypt_offload_*` rules); define retention + integrity; forward to SIEM with alerting. | **Low** | Platform/SecOps — *production* |
| **R-07** | Audit-log **offload plaintext**, **single-site**, **no SIEM alerting**; logs interceptable/repudiable and not actively reviewed. (Transport **bench-verified working** 2026-06-20.) | 2.6 (ISM-1432*/0109*/0859*) | Possible × Moderate → **Medium** | Isolated LAN; disk-assisted queue (no loss on collector blip); auditd local copy; per-source files; LinuxAudit captures USBGuard events. | rsyslog **TLS** (gtls/6514) + bundle CA in image (re-select the 3 waived `rsyslog_encrypt_offload_*` rules); define retention + integrity; forward to SIEM with alerting. | **Low** | Platform/SecOps — *production* |
| **R-13** | **Boot chain unsigned / Secure Boot OFF** in the lab — the UKI and (on the PXE path) iPXE are not signed and SB is not enforced, so a substituted boot artifact would not be rejected by firmware. | 2.10 (ISM-1542*/0312*) | Possible × Major → **Medium** | dm-verity still rejects a tampered *root*; isolated lab LAN; signing is **wired in CI** + key/enrolment procedure + baked `fleet-sb-enroll` ready; only the enforcement is pending. | Enrol fleet `db` (PK/KEK/db per [secure-boot-keys.md](secure-boot-keys.md)); set `SB_KEY`/`SB_CERT` CI secrets; `sbsign` the UKI **and** iPXE; enable Secure Boot on targets. | **Low** | Platform team — *before production* |
| **R-08** | **Placeholder RADIUS CA** (`files/etc/dot1x/radius-ca.pem`) — real EAP-TLS trust anchor not provisioned; auth cannot succeed and trust is unestablished. | 2.4 (ISM-1546*) | Certain (lab) × Major → **Medium** | Documented as a placeholder; environment-specific provisioning is the intended path; no real CA committed. | Provision the environment's real RADIUS CA out-of-band (not committed unless classification permits). | **Low** | Environment owner — *before production* |
| **R-09** | **Host firewall disabled**; host exposes more network surface than necessary. | 2.7 (ISM-1416*) | Possible × Moderate → **Low–Medium** | Isolated LAN; minimal services; egress controlled at the network/serving layer; no kiosk inbound. | Re-enable firewalld with explicit allow rules (NVMe/TCP `:4420`, DHCP, log offload, SSH) once the secure path is verified. | **Low** | Platform/network — *after R-01* |
| **R-10** | **Patch SLA undefined** — no documented cadence for rebuilding/redeploying against new CVEs. | 2.5 (ISM-1144*/1472*) | Likely × Moderate → **Medium** | Atomic rebuild/redeploy model makes patching fast & uniform; reproducible builds. | Define patch cadence & critical-CVE SLA; automate rebuild triggers. | **Low** | Platform team — *roadmap* |
@@ -192,10 +199,12 @@ Likelihood ↓
```
*The heatmap shows pre-treatment positions; every item has a treatment to Low /
Low–Medium. The AO is asked to authorise on the basis that R-01, R-02, R-03, R-08
and R-12 are **closed before production**, and R-04/R-05/R-06/R-07/R-09/R-10/R-11
are either accepted with compensating controls (isolated-LAN lab) or carried on
the POA&M with target dates.*
Low–Medium. The AO is asked to authorise on the basis that **R-01, R-02, R-08,
R-12 and R-13** (and confirming R-03's `enable_stig=true`) are **closed before
production**, and R-04/R-05/R-06/R-07/R-09/R-10/R-11 are either accepted with
compensating controls (isolated-LAN lab) or carried on the POA&M with target
dates. Newly strengthened in v0.2: device control (USBGuard, now Implemented),
admin SELinux confinement (R-05), and STIG applied+verified (R-03 reduced).*
---
@@ -215,6 +224,11 @@ the POA&M with target dates.*
anything flagged **REVIEW** is an unjustified finding.
6. **Confirm lab-only flags are off** in the assessed build: `debug_shell=false`,
`enable_stig=true`, `disable_dot1x=false`, real RADIUS CA in place.
7. **Confirm boot-chain signing is enforced** (R-13): `db` enrolled, Secure Boot
ON, UKI + iPXE signed (`sbverify`). The PXE/iPXE path's SB-OFF cmdline
workaround should be a no-op once SB is on.
8. **Witness device control** (USBGuard): a USB mass-storage device is blocked and
logged, console HID still works.
---