The webhook notifier would previously accept any operator-configured URL
and hand it to http.Client without validation. That exposed two
SSRF classes (CWE-918):
* Reserved-address reachability — a misconfigured or adversarial
webhook URL pointing at 127.0.0.1, ::1, 169.254.169.254 (cloud
metadata), or 0.0.0.0 would succeed, exfiltrating request bodies
to local services or leaking short-lived cloud credentials.
* DNS rebinding — a hostname resolving to a public IP at validation
time and to a reserved IP at dial time would bypass any
URL-string-only check.
Fix installs two independent layers:
* validation.ValidateSafeURL runs at config-ingest time and before
every outbound POST. It rejects non-HTTP(S) schemes, empty hosts,
and literal reserved-IP hosts with a clear operator-facing error.
This is a fast early diagnostic.
* validation.SafeHTTPDialContext is installed on the webhook
http.Transport. It re-resolves the host at dial time, rejects any
resolved address whose address lies in a reserved range (loopback,
link-local, multicast, broadcast, unspecified, IPv6
link-local/multicast), and pins the resolved IP into the final
dial address so the TLS handshake targets the exact IP the guard
approved. This is the authoritative, TOCTOU-safe defence against
DNS rebinding.
The two layers are complementary — validateURL fails fast on obvious
misconfiguration; SafeHTTPDialContext fails closed when DNS changes
between validation and dial.
The existing unexported isReservedIP helper in
internal/service/network_scan.go is extracted into
internal/validation.IsReservedIP with byte-identical behaviour so the
webhook notifier and the network scanner share a single authoritative
reserved-address list. RFC 1918 ranges remain intentionally allowed
(certctl's self-hosted design). Broader unspecified / IPv6 link-local
coverage lives only in the stricter dial-time policy, where it belongs
for outbound HTTP egress.
Test seam: Connector gains an unexported validateURL func field and a
same-package newForTest constructor that installs a permissive
validator and the stdlib default transport. Production callers cannot
reach this constructor because it is unexported; only same-package
tests (package webhook) can use it. Same-package happy-path tests call
newForTest so they can point at httptest loopback servers without
being blocked by the production guard. The four SSRF-rejection tests
that verify the guard itself still call New so they exercise the real,
strict validator. This keeps the production SSRF defence
unconditionally on in real code while preserving legitimate unit-test
coverage.
Tests
-----
* internal/validation/ssrf_test.go (new) — 16-subtest pin on
IsReservedIP that is byte-identical with the original network-
scanner behaviour; ValidateSafeURL accept/reject matrix covering
HTTPS/HTTP, reserved-literal IPv4/IPv6, dangerous schemes
(file/gopher/ftp/javascript/data/ldap/dict/jar), missing hosts,
and malformed inputs; SafeHTTPDialContext rejects literal reserved
addresses and hosts resolving to reserved addresses (DNS-rebinding
coverage via localhost).
* internal/connector/notifier/webhook/webhook_test.go — happy-path
tests switched to newForTest; production-guard SSRF-rejection
tests (TestValidateConfig_RejectsReservedURLs,
TestValidateConfig_RejectsDangerousScheme,
TestPostWebhook_RejectsReservedURL,
TestPostWebhook_RejectsDangerousScheme) continue to call New so
they exercise the unconditionally-installed production validator.
Wire-format invariants preserved
--------------------------------
* Outbound HTTP request shape (method, headers, body, HMAC
signature) unchanged.
* network_scan.go behaviour unchanged — validation.IsReservedIP is
byte-identical with the deleted helper.
* RFC 1918 (10/8, 172.16/12, 192.168/16) remain allowed for both
outbound webhook and CIDR expansion, matching the self-hosted
design.
Verification
------------
* go test -race ./internal/validation/... ./internal/connector/
notifier/webhook/... ./internal/service/... — green.
* Full-suite go test -race ./... — green (GOTMPDIR=/dev/shm to
sidestep full /tmp on the sandbox host).
* Coverage gates pass: service 68.8% >= 55%, handler 83.6% >= 60%,
domain 82.0% >= 40%, middleware 63.8% >= 30%. Overall 67.8%.
Webhook package 91.5% line coverage; validation package
ValidateSafeURL/SafeHTTPDialContext 78-100% per function.
* govulncheck ./... — no vulnerabilities found.
* golangci-lint run on touched H-4 production code — clean. Pre-
existing errcheck/gosimple warnings in scope-adjacent files
(webhook_test.go:270 w.Write, network_scan.go:120/173/265/305)
verified against 3853b74 to predate this commit; left alone per
scope guard.
Operational notes
-----------------
* No migration needed. The guard is pure Go code; existing webhook
configs continue to work unless they point at reserved addresses,
in which case they now fail closed with a clear error.
* Existing operators who rely on webhook POST to 127.0.0.1 or
::1 (e.g., local receivers on the same host as certctl-server)
must expose their receiver on an RFC 1918 address or public IP.
This is deliberate — the threat model for webhook notifiers
includes untrusted operator-supplied URLs.
Scope guard: H-4 only. H-5, H-6, M-*, L-*, and I-* findings remain
open and are tracked separately. No drive-by refactors.
certctl — Self-Hosted Certificate Lifecycle Platform
TLS certificate lifespans are shrinking fast. The CA/Browser Forum passed Ballot SC-081v3 unanimously in April 2025, setting a phased reduction: 200 days by March 2026, 100 days by March 2027, and 47 days by March 2029. Organizations managing dozens or hundreds of certificates can no longer rely on spreadsheets, calendar reminders, or manual renewal workflows. The math doesn't work — at 47-day lifespans, a team managing 100 certificates is processing 7+ renewals per week, every week, forever.
certctl is a self-hosted platform that automates the entire certificate lifecycle — from issuance through renewal to deployment — with zero human intervention. It works with any certificate authority, deploys to any server, and keeps private keys on your infrastructure where they belong. It's free, self-hosted, and covers the same lifecycle that enterprise platforms charge $100K+/year for.
gantt
title TLS Certificate Maximum Lifespan — CA/Browser Forum Ballot SC-081v3
dateFormat YYYY-MM-DD
axisFormat
todayMarker off
section 2015
5 years (1825 days) :done, 2020-01-01, 1825d
section 2018
825 days :done, 2020-01-01, 825d
section 2020
398 days :active, 2020-01-01, 398d
section 2026
200 days :crit, 2020-01-01, 200d
section 2027
100 days :crit, 2020-01-01, 100d
section 2029
47 days :crit, 2020-01-01, 47d
Actively maintained — shipping weekly. Found something? Open a GitHub issue — issues get triaged same-day. CI runs the full test suite with race detection, static analysis, and vulnerability scanning on every commit.
Ready to try it? Jump to the Quick Start — you'll have a running dashboard in under 5 minutes.
Documentation
| Guide | Description |
|---|---|
| Why certctl? | How certctl compares to ACME clients, agent-based SaaS, and enterprise platforms |
| Concepts | TLS certificates explained from scratch — for beginners who know nothing about certs |
| Quick Start | 5-minute setup — dashboard, API, CLI, discovery, stakeholder demo flow |
| Docker Compose Environments | Service-by-service walkthrough of all 4 compose files, env var reference |
| Deployment Examples | 5 turnkey scenarios (ACME+NGINX, wildcard DNS-01, private CA, step-ca, multi-issuer) with migration guides |
| Advanced Demo | Issue a certificate end-to-end with technical deep-dives |
| Architecture | System design, data flow diagrams, security model |
| Feature Inventory | Complete reference of all capabilities, API endpoints, and configuration |
| Connector Reference | Configuration for all issuer, target, and notifier connectors |
| MCP Server | AI integration via Model Context Protocol — setup, available tools, examples |
| OpenAPI 3.1 Spec | API reference guide with endpoint overview (raw spec) |
| Compliance Mapping | SOC 2 Type II, PCI-DSS 4.0, NIST SP 800-57 alignment guides |
| Migrate from certbot | Step-by-step migration from certbot cron jobs to certctl |
| Migrate from acme.sh | Migration guide for acme.sh users, DNS hook compatibility |
| certctl for cert-manager users | How certctl complements cert-manager for mixed infrastructure |
| Test Environment | Docker Compose test environment with real CA backends |
| Testing Guide | Comprehensive test procedures, smoke tests, and release sign-off checklist |
Supported Integrations
Certificate Issuers
| Issuer | Type | Notes |
|---|---|---|
| Local CA (self-signed + sub-CA) | GenericCA |
Sub-CA mode chains to enterprise root (ADCS, etc.) |
| ACME v2 (Let's Encrypt, ZeroSSL, etc.) | ACME |
HTTP-01, DNS-01, DNS-PERSIST-01 challenges. EAB auto-fetch from ZeroSSL. Profile selection (tlsserver, shortlived). |
| step-ca (Smallstep) | StepCA |
JWK provisioner auth, issuance + renewal + revocation |
| OpenSSL / Custom CA | OpenSSL |
Shell script adapter — any CA with a CLI |
| HashiCorp Vault PKI | VaultPKI |
Token auth, synchronous issuance, CRL/OCSP delegated to Vault |
| DigiCert CertCentral | DigiCert |
Async order model, OV/EV support, PEM bundle parsing |
| Sectigo SCM | Sectigo |
3-header auth, DV/OV/EV, collect-not-ready graceful handling |
| Google Cloud CAS | GoogleCAS |
OAuth2 service account, synchronous issuance, CA pool selection |
| AWS ACM Private CA | AWSACMPCA |
Synchronous issuance, configurable signing algorithm/template ARN |
| Entrust Certificate Services | Entrust |
mTLS client certificate auth, synchronous/approval-pending issuance |
| GlobalSign Atlas HVCA | GlobalSign |
mTLS + API key/secret dual auth, serial-based tracking |
| EJBCA (Keyfactor) | EJBCA |
Dual auth (mTLS or OAuth2), self-hosted open-source CA |
Note: ADCS integration is handled via the Local CA's sub-CA mode — certctl operates as a subordinate CA with its signing certificate issued by ADCS. Any CA with a shell-accessible signing interface can be integrated via the OpenSSL/Custom CA connector.
Deployment Targets
| Target | Type | Notes |
|---|---|---|
| NGINX | NGINX |
File write, config validation, reload |
| Apache httpd | Apache |
Separate cert/chain/key files, configtest, graceful reload |
| HAProxy | HAProxy |
Combined PEM file, validate, reload |
| Traefik | Traefik |
File provider deployment, auto-reload via filesystem watch |
| Caddy | Caddy |
Dual-mode: admin API hot-reload or file-based |
| Envoy | Envoy |
File-based with optional SDS JSON config |
| Postfix | Postfix |
Mail server TLS, pairs with S/MIME support |
| Dovecot | Dovecot |
Mail server TLS, pairs with S/MIME support |
| Microsoft IIS | IIS |
Local PowerShell or remote WinRM, PEM→PFX, SNI support |
| F5 BIG-IP | F5 |
iControl REST via proxy agent, transaction-based atomic updates |
| SSH (Agentless) | SSH |
SFTP cert/key deployment to any Linux/Unix server |
| Windows Certificate Store | WinCertStore |
PowerShell Import-PfxCertificate, configurable store/location |
| Java Keystore | JavaKeystore |
PEM→PKCS#12→keytool pipeline, JKS and PKCS12 formats |
| Kubernetes Secrets | KubernetesSecrets |
kubernetes.io/tls Secrets, in-cluster or kubeconfig auth |
Enrollment Protocols
| Protocol | Standard | Use Case |
|---|---|---|
| EST (Enrollment over Secure Transport) | RFC 7030 | Device enrollment, WiFi/802.1X, IoT |
| SCEP (Simple Certificate Enrollment Protocol) | RFC 8894 | MDM platforms (Jamf, Intune), network devices |
| ACME v2 | RFC 8555 | Public CA automated issuance (Let's Encrypt, ZeroSSL) |
| ACME ARI (Renewal Information) | RFC 9773 | CA-directed renewal timing — the CA tells you when to renew |
Standards & Revocation
| Capability | Standard | Notes |
|---|---|---|
| DER-encoded X.509 CRL | RFC 5280 | Per-issuer, signed by issuing CA, 24h validity |
| Embedded OCSP responder | RFC 6960 | Good/revoked/unknown status per issuer |
| S/MIME certificates | RFC 8551 | Email protection EKU, adaptive KeyUsage flags |
| Certificate export | — | PEM (JSON/file) and PKCS#12 formats |
| ACME DNS-PERSIST-01 | IETF draft | Standing validation record, no per-renewal DNS updates |
Notifiers
| Notifier | Type |
|---|---|
| Email (SMTP) | Email |
| Webhooks | Webhook |
| Slack | Slack |
| Microsoft Teams | Teams |
| PagerDuty | PagerDuty |
| OpsGenie | OpsGenie |
All connectors are pluggable — build your own by implementing the connector interface.
Screenshots
Why certctl
Certificate lifecycle tooling falls into two camps: enterprise platforms (Venafi, Keyfactor) that cost six figures and take months to deploy, or single-purpose tools (certbot, cert-manager) that handle one slice of the problem. certctl fills the gap — full lifecycle automation, self-hosted, free, CA-agnostic, and target-agnostic. If you're running certbot cron jobs, manually renewing certs, or stitching together scripts across mixed infrastructure, certctl replaces all of that.
Built for platform engineering and DevOps teams managing 10–500+ certificates, security and compliance teams who need audit trails and policy enforcement for SOC 2, PCI-DSS 4.0, or NIST SP 800-57 (compliance mapping included), and small teams without enterprise budgets who need Venafi-grade automation for a 50-server environment. For a detailed comparison, see Why certctl?
Architecture. Go 1.25 control plane with handler→service→repository layering, PostgreSQL 16 backend (21 tables), and a pull-only deployment model — the server never initiates outbound connections. Agents poll for work. For network appliances and agentless servers, a proxy agent in the same network zone handles deployment via the target's API (WinRM, iControl REST, SSH/SFTP). Background scheduler runs 7 loops: renewal with ARI integration (1h), job processing (30s), agent health (2m), notifications (1m), short-lived cert expiry (30s), network scanning (6h), certificate digest (24h). See Architecture Guide for full system diagrams.
Security-first. Agents generate ECDSA P-256 keys locally — private keys never touch the control plane. API key auth enforced by default with SHA-256 hashing and constant-time comparison. CORS deny-by-default. Shell injection prevention on all connector scripts. SSRF protection (reserved IP filtering) on the network scanner. Atomic idempotency guards on scheduler loops. Issuer and target credentials encrypted at rest with AES-256-GCM. Every API call recorded to an immutable audit trail with actor attribution, body hash, and latency tracking. CI runs race detection, 11 linters, and vulnerability scanning on every commit.
Key design decisions. TEXT primary keys — human-readable prefixed IDs (mc-api-prod, t-platform, o-alice) so you can identify resources at a glance in logs and queries. Idempotent migrations (IF NOT EXISTS, ON CONFLICT DO NOTHING) safe for repeated execution. Dynamic configuration via GUI with AES-256-GCM encrypted credential storage and env var backward compatibility. Handlers define their own service interfaces for clean dependency inversion.
What It Does
Automated lifecycle. Certificates renew and deploy themselves. The scheduler monitors expiration, issues through your CA, and deploys to targets — zero human intervention. ACME ARI (RFC 9773) lets the CA direct renewal timing. Ready for 47-day (SC-081v3) and 6-day (Let's Encrypt shortlived) certificate lifetimes.
Operational dashboard. 26-page GUI covers the entire lifecycle: certificate inventory with bulk ops, deployment timeline with rollback, discovery triage, network scan management, agent fleet health, short-lived credential countdown, approval workflows, and observability metrics. Configure issuers and targets from the dashboard — no env var editing, no server restarts.
Private keys stay on your servers. Agents generate ECDSA P-256 keys locally, submit only the CSR. The control plane never touches private keys. After deployment, agents probe the live TLS endpoint and compare SHA-256 fingerprints to confirm the right certificate is actually being served.
Discovery. Agents scan filesystems for existing PEM/DER certificates. The network scanner probes TLS endpoints across CIDR ranges without agents. Cloud discovery finds certificates in AWS Secrets Manager, Azure Key Vault, and GCP Secret Manager. Continuous TLS health monitoring tracks endpoint status (healthy/degraded/down/cert_mismatch) with configurable thresholds and historical probe data. All discovery modes feed into a unified triage workflow — claim, dismiss, or import what you find.
Policy engine. Certificate profiles constrain key types, max TTL, and EKUs — with crypto policy enforcement that validates every CSR against profile rules before it reaches the issuer. MaxTTL caps are enforced per issuer connector. Approval workflows pause jobs for human review. Ownership tracking routes notifications to the right team. Agent groups match devices by OS, architecture, IP CIDR, and version.
Enrollment protocols. EST server (RFC 7030) for device and WiFi enrollment. SCEP server (RFC 8894) for MDM platforms and network devices. S/MIME issuance with email protection EKU.
Revocation. Single and bulk revocation (by profile, owner, agent, or issuer). DER-encoded X.509 CRL per issuer, signed by the issuing CA. Embedded OCSP responder. RFC 5280 reason codes. Short-lived certs (TTL < 1 hour) are exempt — expiry is sufficient revocation.
Audit and observability. Immutable append-only audit trail records every lifecycle action, every API call, and every approval decision. Prometheus metrics endpoint. Scheduled certificate digest emails. Continuous endpoint health monitoring with state machine transitions and real-time alerts.
Notifications. Slack, Teams, PagerDuty, OpsGenie, SMTP, webhooks. Routed by certificate owner. Daily digest emails with stats and expiring certs.
Multiple interfaces. REST API (111 routes), CLI (12 commands), MCP server (80 tools for Claude, Cursor, Windsurf), Helm chart, web dashboard. Certificate export in PEM and PKCS#12.
First-run onboarding. Wizard guides you through connecting a CA, deploying an agent, and issuing your first certificate. Or start with the pre-populated demo — 32 certificates, 10 issuers, 180 days of history.
For the complete capability breakdown, see the Feature Inventory.
Quick Start
Docker Compose (Recommended)
git clone https://github.com/shankar0123/certctl.git
cd certctl
docker compose -f deploy/docker-compose.yml up -d --build
Wait ~30 seconds, then open http://localhost:8443 in your browser. The onboarding wizard walks you through connecting a CA, deploying an agent, and issuing your first certificate.
Want a pre-populated demo instead? Add the demo override to see 32 certificates across 10 issuers, 8 agents, and 180 days of realistic history:
docker compose -f deploy/docker-compose.yml -f deploy/docker-compose.demo.yml up -d --build
The deploy/ directory has four compose files: docker-compose.yml (base platform), docker-compose.demo.yml (demo data overlay), docker-compose.dev.yml (PgAdmin + debug logging), and docker-compose.test.yml (standalone integration tests with real CA backends). See the Docker Compose Environments Guide for a service-by-service walkthrough, or the Quick Start for a summary.
curl http://localhost:8443/health
# {"status":"healthy"}
Agent Install (One-Liner)
curl -sSL https://raw.githubusercontent.com/shankar0123/certctl/master/install-agent.sh | bash
Detects your OS and architecture, downloads the binary, configures systemd (Linux) or launchd (macOS), and starts the agent. See install-agent.sh for details.
Helm Chart (Kubernetes)
helm install certctl deploy/helm/certctl/ \
--set server.apiKey=your-api-key \
--set postgres.password=your-db-password
Production-ready chart with Server Deployment, PostgreSQL StatefulSet, Agent DaemonSet, health probes, security contexts (non-root, read-only rootfs), and optional Ingress. See values.yaml for all configuration options.
Docker Pull
docker pull shankar0123.docker.scarf.sh/certctl-server
docker pull shankar0123.docker.scarf.sh/certctl-agent
Examples
Pick the scenario closest to your setup and have it running in 2 minutes.
| Example | Scenario |
|---|---|
examples/acme-nginx/ |
Let's Encrypt + NGINX, HTTP-01 challenges |
examples/acme-wildcard-dns01/ |
Wildcard certs via DNS-01 (Cloudflare hook included) |
examples/private-ca-traefik/ |
Local CA (self-signed or sub-CA) + Traefik file provider |
examples/step-ca-haproxy/ |
Smallstep step-ca + HAProxy combined PEM |
examples/multi-issuer/ |
ACME for public + Local CA for internal, one dashboard |
Each directory contains a docker-compose.yml and a README.md explaining the scenario, prerequisites, and customization.
CLI
# Install
go install github.com/shankar0123/certctl/cmd/cli@latest
# Configure
export CERTCTL_SERVER_URL=http://localhost:8443
export CERTCTL_API_KEY=your-api-key
# Usage
certctl-cli certs list # List all certificates
certctl-cli certs renew mc-api-prod # Trigger renewal
certctl-cli certs revoke mc-api-prod --reason keyCompromise
certctl-cli agents list # List registered agents
certctl-cli jobs list # List jobs
certctl-cli status # Server health + summary stats
certctl-cli import certs.pem # Bulk import from PEM file
certctl-cli certs list --format json # JSON output (default: table)
MCP Server (AI Integration)
certctl ships a standalone MCP (Model Context Protocol) server that exposes all 80 API endpoints as tools for AI assistants — Claude, Cursor, Windsurf, OpenClaw, VS Code Copilot, and any MCP-compatible client.
# Install and run
go install github.com/shankar0123/certctl/cmd/mcp-server@latest
export CERTCTL_SERVER_URL=http://localhost:8443
export CERTCTL_API_KEY=your-api-key
mcp-server
Claude Desktop (claude_desktop_config.json):
{
"mcpServers": {
"certctl": {
"command": "mcp-server",
"env": {
"CERTCTL_SERVER_URL": "http://localhost:8443",
"CERTCTL_API_KEY": "your-api-key"
}
}
}
}
Development
make build # Build server + agent binaries
make test # Run tests
make lint # golangci-lint (11 linters)
govulncheck ./... # Vulnerability scan
make docker-up # Start Docker Compose stack
CI runs on every push: go vet, go test -race, golangci-lint, govulncheck, and per-layer coverage thresholds (service 55%, handler 60%, domain 40%, middleware 30%). Frontend CI runs TypeScript type checking, Vitest tests, and Vite production build. 1,668 Go test functions with 625+ subtests, plus frontend test suite.
Roadmap
V1 (v1.0.0) — Shipped
Core lifecycle management — Local CA + ACME v2 issuers, NGINX target connector, agent-side key generation, API auth + rate limiting, React dashboard, CI pipeline with coverage gates, Docker images on GHCR.
V2: Operational Maturity — Shipped
30+ milestones shipping enterprise-grade features for free. Sub-CA mode, ACME DNS-01/DNS-PERSIST-01/EAB/ARI (RFC 9773)/profile selection, step-ca, Vault PKI, DigiCert CertCentral, Sectigo SCM, Google CAS, AWS ACM PCA, Entrust, GlobalSign, EJBCA, OpenSSL/Custom CA issuers. NGINX, Apache, HAProxy, Traefik, Caddy, Envoy, Postfix, Dovecot, IIS (WinRM), F5 BIG-IP, SSH, Windows Certificate Store, Java Keystore, Kubernetes Secrets targets. EST server (RFC 7030) and SCEP server (RFC 8894) enrollment protocols. RFC 5280 revocation with DER CRL + embedded OCSP responder. Certificate profiles, ownership tracking, team assignment, agent groups, interactive approval workflows. Filesystem, network, and cloud secret manager (AWS SM, Azure KV, GCP SM) certificate discovery with triage GUI. Dynamic issuer/target configuration via GUI with AES-256-GCM encrypted storage. First-run onboarding wizard. Post-deployment TLS verification. Certificate export (PEM/PKCS#12). S/MIME support. Prometheus metrics. Scheduled certificate digest emails. Slack, Teams, PagerDuty, OpsGenie, SMTP notifications. MCP server (80 tools), CLI (12 commands), Helm chart. Compliance mapping (SOC 2, PCI-DSS 4.0, NIST SP 800-57). 5 turnkey deployment examples. Agent install script. Migration guides from certbot, acme.sh, and cert-manager. See the Feature Inventory for details.
V3: certctl Pro
Enterprise capabilities for larger deployments are available in the commercial tier.
V4+: Cloud & Scale
Kubernetes cert-manager external issuer, cloud infrastructure targets, extended CA support, and platform-scale features.
License
Certctl is licensed under the Business Source License 1.1. The source code is publicly available and free to use, modify, and self-host. The one restriction: you may not use certctl's certificate management functionality as part of a commercial offering to third parties, whether hosted, managed, embedded, bundled, or integrated. The BSL 1.1 license converts automatically to Apache 2.0 on March 14, 2033.
For licensing inquiries: certctl@proton.me
If certctl solves a problem you have, star the repo to help others find it. Questions, bugs, or feature requests — open an issue.




