Optional: pinned scanner image for the CVE scan runbook

docker/cve-scanner/Dockerfile

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+# Execution container for the Calamari CVE scan runbook.
+#
+# OPTIONAL. The scan works without this image: scan.sh installs Trivy and Grype at
+# runtime when they are not on PATH. This exists to make those versions pinned and
+# reviewable instead.
+#
+# Why it matters for a scheduled scan: the runbook alerts when the reported CVE set
+# changes. With unpinned scanners, a scanner upgrade and a genuine new CVE produce the
+# same signal - "something appeared" - and the difference is what decides whether anyone
+# needs to act. Pinning means a change in the diff is a change in the world, and scanner
+# upgrades become deliberate commits to this file.
+#
+# Build and push (adjust the registry to wherever the runbook's feed points):
+#   docker build -t <registry>/octopusdeploy/calamari-cve-scanner:trivy0.74.0-grype0.117.0 \
+#     docker/cve-scanner
+#   docker push  <registry>/octopusdeploy/calamari-cve-scanner:trivy0.74.0-grype0.117.0
+#
+# Then point the runbook's scan step at it, in
+# Modern-Deployments/.octopus/calamari-cve-scanning/runbooks/scan-cves.ocl:
+#
+#     container {
+#         feed  = "<the docker feed>"
+#         image = "<registry>/octopusdeploy/calamari-cve-scanner:trivy0.74.0-grype0.117.0"
+#     }
+#
+# scan.sh needs no change. It auto-detects both binaries on PATH and skips the install.
+
+FROM octopusdeploy/worker-tools:6.4.0-ubuntu.22.04
+
+# Versions observed in the first green runbook run, 2026-08-18. Bump deliberately, and
+# expect the next scan after a bump to report differences that are the scanner's doing
+# rather than Calamari's.
+ARG TRIVY_VERSION=0.74.0
+ARG GRYPE_VERSION=0.117.0
+
+USER root
+
+RUN set -eux; \
+    curl -sSfL https://raw.githubusercontent.com/aquasecurity/trivy/main/contrib/install.sh \
+      | sh -s -- -b /usr/local/bin "v${TRIVY_VERSION}"; \
+    curl -sSfL https://raw.githubusercontent.com/anchore/grype/main/install.sh \
+      | sh -s -- -b /usr/local/bin "v${GRYPE_VERSION}"; \
+    trivy --version; \
+    grype version
+
+# The vulnerability databases are deliberately NOT baked in. They change daily, and a
+# stale database bundled into an image is exactly the failure this scan exists to catch:
+# it would report a clean result because nobody was looking, not because nothing is wrong.
+# Both tools download the current database on first use in each run.

docker/cve-scanner/README.md

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+# Pinned scanner image for the CVE scan runbook
+
+Optional. Nothing depends on this yet.
+
+## What it is for
+
+`scripts/scan-calamari-cves/scan.sh` installs Trivy and Grype at runtime when they are not
+already on `PATH`. That works, and it is why the runbook needs no image today. It has one
+weakness that only matters once the scan runs unattended:
+
+**An unpinned scanner makes an upgrade indistinguishable from a discovery.** The runbook's
+whole job is to alert when the reported CVE set changes. If the scanner silently moves to a
+new version between runs, findings can appear or vanish because the tool changed rather than
+because Calamari or the world did — and that difference is the entire signal.
+
+Pinning the versions in an image makes scanner upgrades explicit commits to the `Dockerfile`,
+reviewable like any other dependency bump.
+
+## Adopting it
+
+1. Build and push the image (see the header of the `Dockerfile` for the exact commands).
+2. Point the runbook's scan step at it — a two-line change to `container { … }` in
+   `Modern-Deployments/.octopus/calamari-cve-scanning/runbooks/scan-cves.ocl`.
+3. Nothing else changes. `scan.sh` detects both binaries on `PATH` and skips its install
+   step automatically, so the same script keeps working locally with Docker and in the
+   runbook without them.
+
+## Deliberate omission: the vulnerability databases
+
+The databases are not baked in. They change daily — this repo's own README records a CVE
+going from absent to present in the audit source within a single day. A stale database
+frozen into an image would produce a quiet, clean-looking result for the same reason an
+end-of-life runtime does: nobody is looking, not nothing is wrong.
+
+Both tools fetch the current database at run time. On Octopus Cloud dynamic workers there is
+no cache between runs, so this download happens every run regardless of the image.