Subdomain Finder MCP
REMOTE · SUBDOMAIN-FINDER-MCP.LIPMICHAL.WORKERS.DEV
Passive subdomain enumeration from certificate transparency (certspotter, crt.sh) with DNS checks.
Available components
Last scanned (23 hours ago)
Scores higher than 52% of remote servers
Reachable. Last reached 4 Nov 2026.
Category Security
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security63
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one. See how to fix → View diagnostics → Partial
- HTTPS enforcement could not be verified: the plaintext port answered with HTTP 405, which proves neither a plaintext path nor enforcement. View diagnostics → Unverified
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability63
- AI-judged instruction clarity (good).Pass
- Context-footprint check failed: tool/resource definitions use about 960 tokens (~240/item across 4 items; 4 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management7
- Stability observed for 2 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 4 Nov 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.
- 3 Nov 26 0
- Stability: unverified → 0.03 ▲ functional
- 2 Nov 26 65
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 4 Nov 2026 · Probed https://subdomain-finder-mcp.lipmichal.workers.dev/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=lipmichal.workers.dev | CN=WE1,O=Google Trust Services,C=US | 2 Oct 2026 | 31 Dec 2026 | ECDSA 256 | ECDSA-SHA256 | ebf145553d5751d20e0d3cd51e3d7a94 |
| SANs: lipmichal.workers.dev, *.lipmichal.workers.dev | ||||||
| CN=WE1,O=Google Trust Services,C=US (CA) | CN=GTS Root R4,O=Google Trust Services LLC,C=US | 13 Dec 2023 | 20 Feb 2029 | ECDSA 256 | ECDSA-SHA384 | 7ff31977972c224a76155d13b6d685e3 |
| CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) | CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE | 15 Nov 2023 | 28 Jan 2028 | ECDSA 384 | SHA256-RSA | 7fe530bf331343bedd821610493d8a1b |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of subdomain-finder-mcp.lipmichal.workers.dev. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| dev. | present | 60074 | 8 | Verified |
| workers.dev. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://subdomain-finder-mcp.lipmichal.workers.dev/mcp | Verified | 200 | |
| http (plaintext) | http://subdomain-finder-mcp.lipmichal.workers.dev/mcp | Inconclusive | 405 |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
find_subdomains Find subdomains (certificate transparency) ~290
Passive subdomain enumeration for a domain from live certificate transparency logs: certspotter (unexpired certificates) with crt.sh as fallback or for expired history. Returns deduplicated hostnames with first seen and last seen issuance dates, certificate count, issuers and whether a wildcard certificate covers the name, plus the list of wildcard entries. Set resolve=true to also check the first 40 names with DNS over HTTPS and mark live hosts. Passive lookup of public certificate transparency logs; nothing is sent to the target. Use it on assets you own or are authorised to test.
| Name | Type | Req | Description |
|---|---|---|---|
| domain | string | yes | Registered domain, for example "example.com". A URL is accepted and reduced to its host. |
| include_expired | boolean | – | Also include names from expired certificates (uses crt.sh). Finds retired hosts; slower. |
| limit | integer | – | Max hostnames returned (1-1000). Totals are always reported. |
| max_pages | integer | – | certspotter pages to read (1-5). Each page is one request against its keyless rate limit. |
| resolve | boolean | – | Also resolve up to 40 of the returned names over DNS (newest first). |
| source | string | – | auto = certspotter first (fast, unexpired certificates), crt.sh if it fails or throttles. crtsh = crt.sh only (includes expired with include_expired). |
No output schema declared.
No examples provided.
get_certificate_history Get certificate history for a host ~222
Certificates logged in certificate transparency for one hostname (or a whole domain with include_subdomains): issuer organisation and DN, not_before and not_after dates, every SAN on the certificate, revocation status and SHA-256 where certspotter has them. Summarises first and last issuance and the issuers used, which shows CA changes and renewal cadence. Default source certspotter (unexpired); include_expired uses crt.sh for the full history.
| Name | Type | Req | Description |
|---|---|---|---|
| host | string | yes | Hostname, for example "api.example.com" or "example.com". |
| include_expired | boolean | – | Also include names from expired certificates (uses crt.sh). Finds retired hosts; slower. |
| include_subdomains | boolean | – | Also include certificates for names under the host. |
| limit | integer | – | Max certificates returned, newest first (1-100). |
| source | string | – | auto = certspotter first (fast, unexpired certificates), crt.sh if it fails or throttles. crtsh = crt.sh only (includes expired with include_expired). |
No output schema declared.
No examples provided.
resolve_subdomains Resolve subdomains (DNS over HTTPS) ~176
Resolve up to 40 hostnames now through Cloudflare DNS over HTTPS (A, AAAA and the CNAME chain). Each host is marked live, nxdomain, no_records or dangling_cname (a CNAME whose target does not exist, a subdomain takeover lead), and CNAME targets on cloud platforms (S3, Azure, Heroku, GitHub Pages, Netlify, Vercel and others) are named. Also probes a random label per parent domain to detect wildcard DNS. DNS lookups only; no connection is made to the hosts.
| Name | Type | Req | Description |
|---|---|---|---|
| check_wildcard | boolean | – | Probe one random label under each parent domain (max 3) to detect wildcard DNS. |
| hosts | array | yes | Hostnames, for example ["www.example.com", "api.example.com"]. Max 40. |
No output schema declared.
No examples provided.
summarize_attack_surface Summarize attack surface from CT ~191
Reads a domain's subdomains from live certificate transparency and groups them for recon triage: development and test, staging, admin and internal tools, APIs, authentication, mail, remote access (VPN), storage and CDN, legacy and backup. Each group has a count, examples and why it matters. Also returns naming clusters (for example *.eu.example.com), certificate issuers in use, wildcard entries and the 10 newest names. Passive only.
| Name | Type | Req | Description |
|---|---|---|---|
| domain | string | yes | Registered domain, for example "example.com". A URL is accepted and reduced to its host. |
| include_expired | boolean | – | Also include names from expired certificates (uses crt.sh). Finds retired hosts; slower. |
| source | string | – | auto = certspotter first (fast, unexpired certificates), crt.sh if it fails or throttles. crtsh = crt.sh only (includes expired with include_expired). |
No output schema declared.
No examples provided.
How do I install the Subdomain Finder MCP server?
Subdomain Finder MCP is a hosted endpoint at https://subdomain-finder-mcp.lipmichal.workers.dev/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · subdomain-finder-mcp.lipmichal.workers.dev
claude mcp add --transport http theluckystrike-subdomain-finder-mcp 'https://subdomain-finder-mcp.lipmichal.workers.dev/mcp'
What is the Subdomain Finder MCP server?
Subdomain Finder MCP is listed in the public MCP registry as io.github.theluckystrike/subdomain-finder-mcp. Passive subdomain enumeration from certificate transparency (certspotter, crt.sh) with DNS checks. This page covers its hosted endpoint (https://subdomain-finder-mcp.lipmichal.workers.dev/mcp).
Is the Subdomain Finder MCP server safe to use?
Subdomain Finder MCP scores 66 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Subdomain Finder MCP server expose?
Subdomain Finder MCP exposes 4 tools: find_subdomains, resolve_subdomains, get_certificate_history, summarize_attack_surface. Their descriptions and schemas cost roughly 879 tokens of context every time the server is loaded.
Does the Subdomain Finder MCP server require authentication?
No. We connected to Subdomain Finder MCP without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the Subdomain Finder MCP server still maintained?
Subdomain Finder MCP is still listed as active in the MCP registry. We last reached this channel on 4 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.