Hermes Attestation Guardian

Hermes Attestation Guardian

IMPORTANT SCOPE:

• This skill targets Hermes infrastructure only (CLI/Gateway/profile-managed deployments).
• This skill is not an OpenClaw runtime hook package.

Vercel Skills Installation

Install with the Vercel Skills CLI for this harness:

npx skills add prompt-security/clawsec --skill hermes-attestation-guardian -a hermes-agent -y

Release Artifact Verification

For standalone installs, verify the signed release manifest before trusting SKILL.md, skill.json, or the archive. The skill.json file is the package metadata/SBOM source, and the release pipeline signs checksums.json with the ClawSec release key.

set -euo pipefail

SKILL_NAME="hermes-attestation-guardian"
VERSION="0.1.7"
REPO="prompt-security/clawsec"
TAG="${SKILL_NAME}-v${VERSION}"
BASE="https://github.com/${REPO}/releases/download/${TAG}"
ZIP_NAME="${SKILL_NAME}-v${VERSION}.zip"
TMP_DIR="$(mktemp -d)"
trap 'rm -rf "$TMP_DIR"' EXIT

RELEASE_PUBKEY_SHA256="711424e4535f84093fefb024cd1ca4ec87439e53907b305b79a631d5befba9c8"

curl -fsSL "$BASE/checksums.json" -o "$TMP_DIR/checksums.json"
curl -fsSL "$BASE/checksums.sig" -o "$TMP_DIR/checksums.sig"
curl -fsSL "$BASE/signing-public.pem" -o "$TMP_DIR/signing-public.pem"
curl -fsSL "$BASE/$ZIP_NAME" -o "$TMP_DIR/$ZIP_NAME"
curl -fsSL "$BASE/SKILL.md" -o "$TMP_DIR/SKILL.md"
curl -fsSL "$BASE/skill.json" -o "$TMP_DIR/skill.json"

ACTUAL_PUBKEY_SHA256="$(openssl pkey -pubin -in "$TMP_DIR/signing-public.pem" -outform DER | shasum -a 256 | awk '{print $1}')"
if [ "$ACTUAL_PUBKEY_SHA256" != "$RELEASE_PUBKEY_SHA256" ]; then
  echo "ERROR: signing-public.pem fingerprint mismatch" >&2
  exit 1
fi

openssl base64 -d -A -in "$TMP_DIR/checksums.sig" -out "$TMP_DIR/checksums.sig.bin"
openssl pkeyutl -verify -rawin -pubin \
  -inkey "$TMP_DIR/signing-public.pem" \
  -sigfile "$TMP_DIR/checksums.sig.bin" \
  -in "$TMP_DIR/checksums.json" >/dev/null

hash_file() {
  if command -v shasum >/dev/null 2>&1; then
    shasum -a 256 "$1" | awk '{print $1}'
  else
    sha256sum "$1" | awk '{print $1}'
  fi
}

verify_manifest_file() {
  asset="$1"
  path="$2"
  expected="$(jq -r --arg asset "$asset" '.files[$asset].sha256 // empty' "$TMP_DIR/checksums.json")"
  if [ -z "$expected" ]; then
    echo "ERROR: checksums.json missing $asset" >&2
    exit 1
  fi
  actual="$(hash_file "$path")"
  if [ "$actual" != "$expected" ]; then
    echo "ERROR: checksum mismatch for $asset" >&2
    exit 1
  fi
}

expected_archive="$(jq -r '.archive.sha256 // empty' "$TMP_DIR/checksums.json")"
if [ -z "$expected_archive" ]; then
  echo "ERROR: checksums.json missing archive.sha256" >&2
  exit 1
fi
actual_archive="$(hash_file "$TMP_DIR/$ZIP_NAME")"
if [ "$actual_archive" != "$expected_archive" ]; then
  echo "ERROR: archive checksum mismatch" >&2
  exit 1
fi

verify_manifest_file "SKILL.md" "$TMP_DIR/SKILL.md"
verify_manifest_file "skill.json" "$TMP_DIR/skill.json"

echo "Signed release manifest, archive, SKILL.md, and skill.json verified."

Only install or extract the archive after this verification succeeds.

Goal

Generate deterministic Hermes posture attestations, verify them with fail-closed integrity checks, and compare baseline drift using stable severity mapping.

Hermes guard trust policy note

When installing from community sources, configure Hermes guard to use signature-aware trust (trusted signer fingerprint allowlist) rather than source-name-only trust. Unknown signer fingerprints should stay on community policy, and invalid signatures must remain blocked.

Commands

# Generate attestation (default output: ~/.hermes/security/attestations/current.json)
node scripts/generate_attestation.mjs

# Generate with explicit policy + deterministic timestamp
node scripts/generate_attestation.mjs \
  --policy ~/.hermes/security/attestation-policy.json \
  --generated-at 2026-04-15T18:00:00.000Z \
  --write-sha256

# Verify schema + canonical digest
node scripts/verify_attestation.mjs --input ~/.hermes/security/attestations/current.json

# Verify with baseline diff (baseline must be authenticated)
node scripts/verify_attestation.mjs \
  --input ~/.hermes/security/attestations/current.json \
  --baseline ~/.hermes/security/attestations/baseline.json \
  --baseline-expected-sha256 <trusted-baseline-sha256> \
  --fail-on-severity high

# Optional detached signature verification
node scripts/verify_attestation.mjs \
  --input ~/.hermes/security/attestations/current.json \
  --signature ~/.hermes/security/attestations/current.json.sig \
  --public-key ~/.hermes/security/keys/attestation-public.pem

# Refresh advisory feed verification state (fail-closed by default)
node scripts/refresh_advisory_feed.mjs

# Check advisory feed verification + feed summary
node scripts/check_advisories.mjs

# Guarded advisory-aware skill verification gate (returns 42 on advisory match without explicit confirm)
node scripts/guarded_skill_verify.mjs --skill some-skill --version 1.2.3

# Explicit operator acknowledgement path for advisory matches
node scripts/guarded_skill_verify.mjs --skill some-skill --version 1.2.3 --confirm-advisory

# Optional temporary unsigned bypass (dangerous; emergency-only)
HERMES_ADVISORY_ALLOW_UNSIGNED_FEED=1 node scripts/refresh_advisory_feed.mjs --allow-unsigned

# Preview scheduler config without mutating user schedule state
node scripts/setup_attestation_cron.mjs --every 6h --print-only

# Apply managed scheduler block
node scripts/setup_attestation_cron.mjs --every 6h --apply

# Preview advisory check scheduler config (guarded flow, print-only default)
node scripts/setup_advisory_check_cron.mjs --every 6h --skill some-skill --print-only

# Apply advisory check scheduler block (uses guarded_skill_verify flow)
node scripts/setup_advisory_check_cron.mjs --every 6h --skill some-skill --version 1.2.3 --apply

# Emergency-only: unsigned bypass for scheduled advisory checks (do not keep enabled)
node scripts/setup_advisory_check_cron.mjs --every 6h --skill some-skill --allow-unsigned --apply

WARNING: --allow-unsigned in scheduled commands is incident-response only. Remove it immediately after recovery and restore signed advisory verification.

Attestation payload (implemented)

The generator emits:

• schema_version, platform, generated_at
• generator metadata (skill + node version)
• host metadata (hostname/platform/arch)
• posture.runtime (gateway enabled flags + risky toggles)
• posture.feed_verification status (verified|unverified|unknown) sourced from $HERMES_HOME/security/advisories/feed-verification-state.json
• posture.integrity watched_files and trust_anchors (existence + sha256)
• digests.canonical_sha256 over a stable canonical JSON representation

Fail-closed behavior

Verifier exits non-zero when:

• schema validation fails
• canonical digest algorithm is unsupported or digest binding mismatches
• expected file sha256 mismatches (if configured)
• detached signature verification fails (if configured)
• baseline is provided without authenticated trust binding (--baseline-expected-sha256 and/or baseline signature + public key)
• baseline authenticity or baseline schema/digest validation fails
• baseline diff highest severity is at/above --fail-on-severity (default: critical)

Severity messages are emitted as INFO / WARNING / CRITICAL style lines.

Side effects

• generate_attestation.mjs writes one JSON file (and optional .sha256) under $HERMES_HOME/security/attestations.
• verify_attestation.mjs is read-only.
• refresh_advisory_feed.mjs writes verified feed cache + verification state under $HERMES_HOME/security/advisories.
• check_advisories.mjs is read-only.
• guarded_skill_verify.mjs re-runs feed refresh/verification (same advisory cache + state side effects) and then performs advisory-aware gate checks.
• setup_attestation_cron.mjs is read-only unless --apply is provided.
• setup_attestation_cron.mjs --apply rewrites only the current user managed schedule block delimited by:
  • # >>> hermes-attestation-guardian >>>
  • # <<< hermes-attestation-guardian <<<
• setup_advisory_check_cron.mjs is read-only unless --apply is provided.
• setup_advisory_check_cron.mjs --apply rewrites only the current user advisory-check managed schedule block delimited by:
  • # >>> hermes-attestation-guardian-advisory-check >>>
  • # <<< hermes-attestation-guardian-advisory-check <<<
  • generated command path uses guarded_skill_verify.mjs (advisory-aware gate), not raw check_advisories.mjs

Advisory feed override knobs

The default signed advisory feed is consolidated: it can contain NVD CVEs, approved community advisories, and provisional GHSA-without-CVE records. Hermes matching still gates on affected package names and supported version ranges.

• Source selection: HERMES_ADVISORY_FEED_SOURCE=auto|remote|local
• Remote artifacts: HERMES_ADVISORY_FEED_URL, HERMES_ADVISORY_FEED_SIG_URL, HERMES_ADVISORY_FEED_CHECKSUMS_URL, HERMES_ADVISORY_FEED_CHECKSUMS_SIG_URL
• Local artifacts: HERMES_LOCAL_ADVISORY_FEED, HERMES_LOCAL_ADVISORY_FEED_SIG, HERMES_LOCAL_ADVISORY_FEED_CHECKSUMS, HERMES_LOCAL_ADVISORY_FEED_CHECKSUMS_SIG
• Pinned key override: HERMES_ADVISORY_FEED_PUBLIC_KEY (default is built-in pinned key)
• Optional checksum toggle: HERMES_ADVISORY_VERIFY_CHECKSUM_MANIFEST (default: enabled)
• UNSAFE emergency bypass only: HERMES_ADVISORY_ALLOW_UNSIGNED_FEED=1

Notes

• Hermes scan + test context is .mjs-based by design:
  • runtime scripts: scripts/*.mjs
  • shared libraries: lib/*.mjs
  • regression tests: test/*.test.mjs
• Keep .mjs paths/extensions stable so scanner scope, SBOM wiring, and test harness references stay valid.
• Default output root is ~/.hermes/security/attestations/.
• No destructive remediation actions (delete/restore/quarantine) are implemented.
• Advisory feed remote URL allowlisting is not implemented in v0.0.2; operators must explicitly trust configured feed/checksum endpoints.
• Guarded advisory version matching supports >=, <=, >, <, =, ^, ~, wildcard *, AND comparator sets separated by spaces or commas, and SemVer prerelease precedence. OR and hyphen ranges remain unsupported and fail closed.
• Valid CPE 2.3 entries from the consolidated NVD feed are accepted as non-package metadata and ignored by package-name matching. Malformed CPE entries still fail closed.
• Operator policy file is optional JSON with:
  • watch_files: list of file paths
  • trust_anchor_files: list of file paths

Source: prompt-security/clawsec → skills/hermes-attestation-guardian/SKILL.md