claude-plugins-official/plugins/code-modernization/commands/modernize-harden.md

---
description: Security vulnerability scan with a reviewable remediation patch — OWASP, CWE, CVE, secrets, injection
argument-hint: <system-dir> [--show-secrets]
---

Run a **security hardening pass** on the legacy system: find
vulnerabilities, rank them, and produce a reviewable patch for the
critical ones. Parse arguments flag-independently: the system dir
(referred to as `$1` below) is the first non-flag token in `$ARGUMENTS`;
`--show-secrets` may appear anywhere.

This command never edits `legacy/` — it writes findings and a proposed patch
to `analysis/$1/`. The user reviews and applies (or not).

## Step 0 — Secrets quarantine setup

Findings files get shared, committed, and pasted into decks — discovered
credential values must never land in them. Before any scanning:

1. Ensure `analysis/.gitignore` exists and contains the lines
   `SECRETS.local.md` and `*.local.patch`. Create the file or append the
   missing lines.
2. If the project is a git repo, verify with
   `git check-ignore -q analysis/$1/SECRETS.local.md` — if that exits
   non-zero, fix the ignore rule before proceeding. Do not write any
   findings until this check passes.
3. **If there is no git repo** (check for `.svn`/`.hg`/`CVS` too — a
   `.gitignore` protects nothing under another VCS): refuse
   `--show-secrets`, and write `SECRETS.local.md` and any `.local.patch`
   file to `~/.modernize/$1/` instead of the project tree, telling the
   user where they went and why.

All secret values in every shareable artifact this command produces are
**masked** (`AKIA****`, `password=****`) and cited by `file:line`. Raw
values may appear in exactly two places, both gitignored: the
`*.local.patch` remediation hunks (unavoidably — see Remediate) and, only
with `--show-secrets`, `SECRETS.local.md`. Never in SECURITY_FINDINGS.md
or patch commentary.

## Scan

Spawn the **security-auditor** subagent:

"Adversarially audit legacy/$1 for security vulnerabilities. Cover what's
relevant to the stack: injection (SQL/NoSQL/OS command/template), broken
auth, sensitive data exposure, access control gaps, insecure deserialization,
hardcoded secrets, vulnerable dependency versions, missing input validation,
path traversal. For each finding return: CWE ID, severity
(Critical/High/Med/Low), file:line, one-sentence exploit scenario, and
recommended fix. Run any available SAST tooling (npm audit, pip-audit,
OWASP dependency-check) and include its raw output. Mask every discovered
credential value per your secret-handling rules — file:line plus a 2–4
character masked preview, never the value itself."

## Triage

Write `analysis/$1/SECURITY_FINDINGS.md`:
- Summary scorecard (count by severity, top CWE categories)
- Findings table sorted by severity
- Dependency CVE table (package, installed version, CVE, fixed version)

If any hardcoded credentials were found, also write
`analysis/$1/SECRETS.local.md` (the gitignored quarantine file from Step 0):
one row per credential — masked preview, `file:line`, credential type, what
it appears to grant access to, production/test guess, and a rotation
recommendation. With `--show-secrets`, append the raw value column here —
this file only. SECURITY_FINDINGS.md gets a one-line pointer:
"N hardcoded credentials found — inventory in SECRETS.local.md (gitignored;
not for sharing)."

## Remediate

For each **Critical** and **High** finding, draft a minimal, targeted fix.
Do **not** edit `legacy/` — write fixes as unified diffs with **paths
relative to the project root** (`legacy/$1/...`), applied from the project
root, with a comment line above each hunk citing the finding ID it
addresses (`# SEC-001: parameterize the query`).

**Credential findings split into two files.** A diff that removes a
hardcoded secret necessarily contains the raw value on its `-` and
context lines — that cannot go in the shareable patch:

- `analysis/$1/security_remediation.patch` (shareable) — every
  non-credential hunk, plus for each credential finding a comment-only
  placeholder: `# SEC-NNN: credential remediation — hunk in
  security_remediation.local.patch (gitignored; not for sharing)`.
- `analysis/$1/security_remediation.local.patch` (gitignored in Step 0) —
  the real, applyable hunks for credential findings only.

Add a **Remediation Log** section to SECURITY_FINDINGS.md mapping each
finding ID → one-line summary of the proposed fix and which patch file
carries the hunk.

## Verify

Spawn the **security-auditor** again to **review both patches** against
the original code:

"Review analysis/$1/security_remediation.patch and
analysis/$1/security_remediation.local.patch against legacy/$1. For each
hunk: does it fully remediate the cited finding? Does it introduce new
vulnerabilities or change behavior beyond the fix? Confirm no raw
credential values appear anywhere in the shareable patch. Return one
verdict per hunk: RESOLVES / PARTIAL / INTRODUCES-RISK, with a one-line
reason."

Add a **Patch Review** section to SECURITY_FINDINGS.md with the verdicts.
If any hunk is PARTIAL or INTRODUCES-RISK, revise the patch and re-review.

## Present

Tell the user the artifacts are ready:
- `analysis/$1/SECURITY_FINDINGS.md` — findings, remediation log, patch review
- `analysis/$1/security_remediation.patch` — review, then apply **from the
  project root**: `git apply analysis/$1/security_remediation.patch`
  (if `legacy/$1` is a symlink, use `git apply --unsafe-paths` or apply
  with `patch -p0` from the project root)
- `analysis/$1/security_remediation.local.patch` — the credential fixes;
  apply the same way, and rotate the affected credentials regardless
- Re-run `/modernize-harden $1` after applying to confirm resolution

Suggest: `glow -p analysis/$1/SECURITY_FINDINGS.md`