Ctfr

6c7fecd

Abusing Certificate Transparency logs for getting HTTPS websites subdomains.

Verified 24 Sept 2026
git 6c7fecd
GPL-3.0
2.1k stars

Source on GitHub · Pinned commit · Markdown

Install and run

otlite install ctfr
Installs github.com/UnaPibaGeek/ctfr at 6c7fecd into its own virtualenv. otlite lists what it will install and asks before it starts.
otlite run ctfr -- d:example.com
python ctfr.py receives python ctfr.py --domain example.com

No otlite yet? Install it in one line

curl -fsSL https://get.otinstaller.com/otlite | sh

Linux and macOS, no Docker. It uses your Python and pipx when both are there, and otherwise brings its own Python. About otlite · otlite docs

What it takes

Typed inputs after -- become Ctfr's own arguments. Anything else after -- passes through unchanged, so every option of the tool still works.

Input	With otlite	`python ctfr.py` receives
Domain`d:`	`otlite run ctfr -- d:example.com`	`python ctfr.py --domain example.com`

What a run leaves

Every run is saved under results/ where you run otlite (or --output, or OTLITE_RESULTS_DIR): what the tool printed, a sidecar with how it ran, and an envelope.

results/ctfr/example.com/<time>_ctfr_example.com_<run id>.txt
results/ctfr/example.com/<time>_ctfr_example.com_<run id>.meta.json
results/ctfr/example.com/<time>_ctfr_example.com_<run id>.envelope.json

{
  "envelope": 1,
  "tool": "ctfr@6c7fecd",
  "runtime": "otlite",
  "input": { "target": "example.com" },
  "case": null,
  "started_at": "…", "ended_at": "…", "duration_ms": …,
  "exit_code": 0,
  "status": "complete",
  "entities": [{ "type": "url", "value": "…" }, …],
  "warnings": [],
  "output": { "path": "results/ctfr/example.com/<time>_ctfr_example.com_<run id>.txt", "sha256": "…", "bytes": … }
}

The envelope's shape, the same for every tool; values elided. Its entities are the emails, domains, IP addresses and URLs found in the output, or the tool's own when it prints them.

otlite results --tool ctfr

otlite extract ctfr

otlite diff ctfr example.com

List the saved runs, pull out every indicator, or compare the two latest runs against the same target.

With other tools

These run it with every other installed tool that takes the same input, a few at a time, and save each run:

otlite run --all d:example.com

otlite auto example.com

It is in the domain-recon playbook:

otlite playbook domain-recon example.com

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