VMware Harden

vmware-harden

Disclaimer: Community-maintained open-source project. Not affiliated with, endorsed by, or sponsored by VMware, Inc. or Broadcom Inc. "VMware", "vSphere", "ESXi", and "NSX" are trademarks of Broadcom. Source code is publicly auditable at github.com/vmware-skills/VMware-Harden under the MIT license.

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AI-native VMware compliance and baseline enforcement. Sibling to the vmware-* skill family.

• Read-only against vSphere: all 8 MCP tools carry the [READ] marker and none mutate managed VMware infrastructure; scan_target writes only to the local twin DB (a cache of its own observations). See Read-only by design.

GA family member (since v1.5.18)

Production-ready compliance platform with 9 built-in baselines (CIS ESXi 8.0 + 9.0, vSphere SCG v8 + v9, vSphere 9 STIG-aligned, 等保 2.0 三级, PCI-DSS 4.0, EU NIS2, BSI IT-Grundschutz) carrying 99 rules, multi-vCenter Twin, drift detection, LLM Remediation Advisor, MCP server with 8 audited tools, web dashboard, and vmware-harden doctor environment diagnostics.

Quickstart

# The collectors extra is what makes `scan` work: harden reads inventory
# through vmware-aiops / vmware-storage / vmware-nsx-security, and `uv tool
# install` gives each tool its own environment — installing them separately
# puts them where harden cannot import them from.
uv tool install "vmware-harden[collectors]"

# Reporting on an existing twin DB needs no collectors:
#   uv tool install vmware-harden

# List built-in baselines
vmware-harden baseline list

# Run a scan
vmware-harden scan --target <vcenter-name> --baseline cis-vmware-esxi-8.0-subset

# Or use 等保 2.0 三级 (国内合规独家)
vmware-harden scan --target <vc> --baseline dengbao-2.0-level3-vmware

# View results
vmware-harden report
vmware-harden drift

# Generate remediation suggestions
export ANTHROPIC_API_KEY=...  # optional; falls back to mock without
vmware-harden advise --all-critical

# Web dashboard
vmware-harden web --port 8080  # → http://127.0.0.1:8080

Reading a result: violations alone are not a verdict

A rule can only judge configuration that was actually gathered, and that fails in two independent ways. A rule whose attribute no collector produces is not executed at all. A rule that does run can still learn nothing about one particular host, because there the value came back absent or as the N/A sentinel — an unreachable host, an account without the privilege, a setting the ESXi build does not have. Neither is reported as passing:

$ vmware-harden report
No violations among the checks that could be made.

16 of 20 rules could not be evaluated — no collector provides the data they
check, so their result is unknown, not compliant. 6 of 8 per-node checks could
not be made across 2 node(s): the rules ran, but the values they read were
missing on those nodes, so those nodes are unknown rather than compliant.
Not evaluated:
  cis-esxi-2.1.1   no collector writes host.ntp_enabled
  ...
Not judged on these nodes (data missing):
  cis-esxi-2.2.1   esx-02    esxi_build
  ...

--format json returns {"violations": [...], "coverage": {...}}, and the MCP tools return the same coverage block, so an agent reading violations: 0 cannot conclude "compliant" on its own. Before v1.9.0 the uncollected-attribute rules matched zero rows and were silently counted as passes; before v1.10.0 the per-node case was, too. See RELEASE_NOTES.md.

The two lists call for different work: the first is waiting on a collector, the second on that node's reachability and the scanning account's privileges.

Offline / Air-Gapped Install (from source)

This project uses the modern PEP 517 build system (hatchling), so there is no setup.py by design — that is expected, not a missing file. If you cloned the source and hit ERROR: File "setup.py" or "setup.cfg" not found ... editable mode currently requires a setuptools-based build, your pip is older than 21.3 and cannot do an editable (-e) install with a non-setuptools backend. Editable mode is a developer convenience, not needed to run the tool — do one of:

# From the source tree — a normal (non-editable) install builds a wheel:
pip install .              # NOT  pip install -e .

# ...or upgrade pip first, and editable works too:
pip install --upgrade pip && pip install -e .

For a truly air-gapped host, build the wheels on a connected machine and copy them over — the target then needs no network:

# On a connected machine, collect this package + its dependencies as wheels:
pip wheel . -w dist        # → dist/*.whl   (or: uv build, for just this package)

# Copy dist/ to the air-gapped host, then install offline:
pip install --no-index --find-links dist vmware-harden

Read-Only by Design

vmware-harden is read-only against vSphere and NSX — all 8 MCP tools carry the [READ] marker, and none mutate managed VMware infrastructure. scan_target writes only to the local twin DB (~/.vmware-harden/twin.duckdb), a cache of its own observations rather than managed infrastructure. Remediation is never applied by this skill; it is deferred to vmware-pilot, which provides approval gating and audit trails for write operations.

Built-in baselines

Baseline	Rules	Applies to	Source
cis-vmware-esxi-8.0-subset	20	host	CIS Benchmark v1.0
vsphere-scg-v8-subset	15	host, vm	VMware vcf-security-and-compliance-guidelines
dengbao-2.0-level3-vmware	20	host, vm, datastore, dfw_rule	GB/T 22239-2019 三级
pci-dss-4.0-vmware	10	host, dfw_rule	PCI-DSS v4.0
eu-nis2-vmware	12	host, dfw_rule	EU NIS2 Directive (Articles 21/23, Annex I)
bsi-itgs-basisabsicherung-vmware	10	host	BSI IT-Grundschutz (OPS.1.1.4 + SYS.1.1)
cis-vmware-esxi-9.0-subset	20	host	Inherits cis-vmware-esxi-8.0-subset via extends:
vsphere-scg-v9-subset	15	host, vm	Inherits vsphere-scg-v8-subset via extends:
vsphere-stig-v9-subset ⚠️ experimental	12	host	vSphere 9 STIG-aligned host advanced settings (DoD/DISA STIG content) — collector verified on ESXi 8.0.3; not yet run against 9.x

baseline list returns 9 IDs: the 7 rule-bearing baselines above (99 rules total) plus the two v9 aliases, which carry no rules of their own and resolve to their v8 parent's.

VCF 9.0 / 9.1 Compatibility

The existing baselines (cis-vmware-esxi-8.0-subset, vsphere-scg-v8, dengbao-2.0-level3-vmware, pci-dss-4.0-vmware) scan VCF 9.0 / 9.1 clusters successfully — most rules target host advanced settings stable across 8.x → 9.x. cis-vmware-esxi-9.0-subset and vsphere-scg-v9-subset ship today as extends: aliases of their v8 parents — same rules, a v9-named ID to scan and report under. Rules specific to 9.x will be added to them as Broadcom publishes the v9 guides.

vsphere-stig-v9-subset is a rule-bearing STIG-aligned baseline: 12 host advanced-setting controls (account lockout, password policy, DCUI access, shell/DCUI timeouts, MOB, guest BPDU, remote syslog) mapped to the official open-source vSphere STIG content (MITRE InSpec / Cinc Auditor). Status: experimental. Its checks read ESXi host advanced settings the host collector fetches via a config.option PropertyCollector pass. That pass was verified end-to-end on 2026-08-13 against a live standalone ESXi 8.0.3 (build 24280767): all 12 attributes came back populated, with values in the shapes the rules expect (account_lock_failures=5, dcui_access='root', password_quality_control='retry=3 min=disabled,disabled,disabled,7,7', mob_enabled=False, syslog_remote_host=''), and the scan raised 3 genuine violations. Still unverified, and why the status stays experimental: ESXi 9.x, which is what this baseline actually targets, and any vCenter-managed multi-host inventory. Treat results on 9.x as non-authoritative. The v1.9.0 undetermined mechanism does not cover a failed fetch on its own: it refuses a rule when no collector declares the attribute, a static check against the vocabulary, and these STIG attributes are declared, so their rules do run. If the real PropertyCollector pass comes back empty on live hardware, the attribute is simply absent and the rule again matches zero rows. v1.10.0 catches that case — such a host is recorded as a per-node gap (coverage.undetermined_node_checks) rather than a pass, so an unverified collector shows up as unjudged hosts instead of a clean report. What remains unverified is whether the pass returns the right values, which no coverage mechanism can tell you. The baseline's status field is surfaced by list_baselines and describe_stig_content_sync so a scan self-declares this caveat. It is a content sync, not an API wrapper — VCF Operations 9.1 Automated Configuration Compliance (ACC) / Security Posture Management (SPM) is UI- and schedule-driven and exposes no public compliance REST API. For continuous, fleet-wide enforcement and automated remediation, use VCF Operations SPM/ACC (UI); vmware-harden is the API-scriptable, DuckDB-persisted, cross-target point-in-time scanner. See references/stig-content-sync.md and inspect the catalog with vmware-harden stig controls.

Official Broadcom References

• Security Configuration Guides: https://core.vmware.com/security/ — vSphere SCG v8 / future v9
• SDKs: https://developer.broadcom.com/sdks — VCF Python SDK (for fetching host config via REST)
• CIS Benchmarks: https://www.cisecurity.org/cis-benchmarks/ — CIS VMware ESXi Benchmark v1.0 (8.0 / future 9.0)

Custom baselines

vmware-harden baseline validate ./my-strict.yaml
vmware-harden baseline import ./my-strict.yaml --name my-strict-cis
vmware-harden scan --target <vc> --baseline my-strict-cis

YAML supports extends: for inheriting from a built-in baseline. See skills/vmware-harden/references/cli-reference.md.

MCP server

vmware-harden mcp  # stdio MCP server (legacy alias: vmware-harden-mcp)

Configure your MCP client with one of examples/mcp-configs/*.json. 8 read-only tools: list_baselines, get_baseline_rules, list_stig_controls, describe_stig_content_sync, list_violations, get_remediation, list_drift_events, scan_target.

Architecture

• Estate Digital Twin — DuckDB single file at ~/.vmware-harden/twin.duckdb. Multi-target safe via target prefix on all node IDs.
• Collectors — lazy-import sibling vmware-* skills (no spawn overhead). All scans are READ; writes deferred to vmware-pilot.
• Baseline schema — Pydantic v2, strict (extra="forbid"), extends: inheritance, user-dir override.
• Drift — pure diff function with optional persistence; auto-runs after every scan.
• Advisor — LLM-driven Suggestion generation; Anthropic provider with prompt caching; mock fallback for tests / no-API-key environments.
• Audit — every MCP tool wrapped with @vmware_tool from family vmware-policy.
• Web — FastAPI + Jinja2 + Tailwind/HTMX/ECharts CDN.

Lab regression

export VMWARE_HARDEN_LAB_TARGET=<your-vc>
pytest tests/eval/regression -v -m lab

Family

• vmware-aiops — host inventory + ops (used by harden's HostCollector)
• vmware-monitor — read-only counterpart
• vmware-storage — datastore inventory
• vmware-nsx-security — DFW inventory
• vmware-pilot — execute remediations (writes; out of scope for harden)
• vmware-policy — @vmware_tool audit decorator

Acceptance criteria (v1.5.18 GA)

• 221 tests passing
• Bandit: 0 issues at any severity
• All 8 MCP tools audited
• SKILL.md ≤ 3000 words, family-convention compliant
• SECURITY.md with 6 elements + Broadcom disclaimer
• 9 built-in baselines (99 rules across 7 rule-bearing sets + 2 v9 aliases)
• vmware-harden doctor for environment diagnostics
• GA member of vmware-* family (version-aligned at 1.5.28)

References

• Family CLAUDE.md: CLAUDE.md at the monorepo root

Remote access (HTTPS) and limiting tools

By default vmware-harden mcp speaks stdio to one local client and offers every tool. Two options change that (vmware-policy ≥ 1.21.0).

Serve over HTTPS so clients on other machines can connect. Every caller needs a bearer token:

vmware-audit token create alice          # prints the token once; give it to alice
vmware-audit token list                  # names only
vmware-audit token revoke alice          # refused from its next request, no restart
vmware-harden mcp --transport https --host 0.0.0.0 --port 8443 \
    --cert /etc/vmware-mcp/server.pem --key /etc/vmware-mcp/server-key.pem \
    --public-name mcp.example.com

Connect a client (Claude Code shown; any MCP client that supports streamable HTTP and custom headers works):

claude mcp add --transport http vmware-harden https://mcp.example.com:8443/mcp \
    --header "Authorization: Bearer $VMWARE_MCP_TOKEN"

{
  "mcpServers": {
    "vmware-harden": {
      "type": "http",
      "url": "https://mcp.example.com:8443/mcp",
      "headers": { "Authorization": "Bearer ${VMWARE_MCP_TOKEN}" }
    }
  }
}

• The server will not start without a token, refuses Host/Origin values outside --public-name, and checks before it binds that unauthenticated requests get 401. Use a certificate your clients trust for those names.
• Behind a TLS-terminating reverse proxy on the same machine use --transport http --host 127.0.0.1 --public-name mcp.example.com and pass the Authorization header through.
• Behind a load balancer or gateway on another machine, keep --transport https (a self-signed certificate is fine), list in --public-name the host name the balancer sends as Host, and have it forward Authorization. Its health probe can use GET /healthz, which needs no token and returns only {"status": "ok"} (vmware-policy ≥ 1.23.0).
• Send traceparent or X-Request-ID with each request to have it stored on the audit row; vmware-audit log --correlation-id ID then finds the calls behind one platform request.
• The audit log records each caller as token:<name>. Calls naming different targets run in parallel; calls that name no target run one at a time, so name the target when several people share a server.
• Everyone who can reach the endpoint acts with this server's account. Tokens identify callers; they grant nothing on the platform. Run one endpoint per privilege level.
• Several people or roles on one endpoint: run vmware-audit roles enable once, then give each token a role (vmware-audit token create NAME --role reader, or a role in roles.yaml naming tools and targets; vmware-policy ≥ 1.24.0). A role limits what the token may call on this endpoint; it cannot grant more than the account has. For a target-limited role, scan_target's target is checked against vmware-aiops' config; the datastore and DFW collectors look the same name up in vmware-storage's and vmware-nsx-security's configs, so a name must mean the same system in all three. See vmware-policy's README, "Roles for network callers".

Limiting tools: every tool of this server is read-only, so --expose read changes nothing here; it exists for the write-capable skills. Least privilege comes from the account the server uses.

Details: skills/vmware-harden/references/setup-guide.md ("Serving MCP over HTTPS", "Limiting which tools are offered").

License

MIT