analyzing-tls-certificate-transparency-logs

analyzing-tls-certificate-transparency-logs is a skill for Claude Code, Codex from autohandai/community-skills. It costs 67 tokens per session (359 once invoked), scanned A, original, Apache-2.0.

A guide for searching Certificate Transparency logs, public records of issued TLS certificates, to find suspicious certificates for or near your domains. It covers lookalike domains, unexpected certificate issuers, and suspicious subdomains.

In plain words
What is it for?
Use it to monitor certificates, find typosquatting and brand-impersonation domains, flag unexpected certificate authorities, and investigate phishing infrastructure.
Why use it?
It can expose phishing infrastructure or unauthorized certificates before they are used widely. Searching certificate records gives visibility into domains that resemble your brand.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to monitor certificates, find typosquatting and brand-impersonation domains, flag unexpected certificate authorities, and investigate phishing infrastructure.

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Install with agentmods
npx agentmods add skills/autohandai/community-skills/analyzing-tls-certificate-transparency-logs
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add autohandai/community-skills --skill analyzing-tls-certificate-transparency-logs
Clone the repo
git clone --depth 1 https://github.com/autohandai/community-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for analyzing-tls-certificate-transparency-logs

README.md
[![agentmods](https://agentmods.dev/badge/skills/autohandai/community-skills/analyzing-tls-certificate-transparency-logs/github.svg)](https://agentmods.dev/skills/autohandai/community-skills/analyzing-tls-certificate-transparency-logs)
Your own site
<a href="https://agentmods.dev/skills/autohandai/community-skills/analyzing-tls-certificate-transparency-logs"><img src="https://agentmods.dev/badge/skills/autohandai/community-skills/analyzing-tls-certificate-transparency-logs/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for analyzing-tls-certificate-transparency-logs

Your own site · 80×15
<a href="https://agentmods.dev/skills/autohandai/community-skills/analyzing-tls-certificate-transparency-logs"><img src="https://agentmods.dev/badge/skills/autohandai/community-skills/analyzing-tls-certificate-transparency-logs.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 359 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00067 $0.00359
Opus 5 $0.00034 $0.00179
Sonnet 5 $0.00013 $0.00072
Haiku 4.5 $0.00007 $0.00036

Measured 9d ago against content hash 29183850644e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

analyzing-tls-certificate-transparency-logs scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/agent.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

analyzing-tls-certificate-transparency-logs/SKILL.md · 52 lines

What it actually says

Analyzing TLS Certificate Transparency Logs

Instructions

Query crt.sh Certificate Transparency database to find certificates issued for domains similar to your organization's brand, detecting phishing infrastructure.

from pycrtsh import Crtsh

c = Crtsh()
# Search for certificates matching a domain
certs = c.search("example.com")
for cert in certs:
    print(cert["id"], cert["name_value"])

# Get full certificate details
details = c.get(certs[0]["id"], type="id")

Key analysis steps:

  1. Query crt.sh for all certificates matching your domain pattern
  2. Identify certificates with typosquatting variations (Levenshtein distance)
  3. Flag certificates from unexpected CAs
  4. Monitor for wildcard certificates on suspicious subdomains
  5. Cross-reference with known phishing infrastructure

Examples

from pycrtsh import Crtsh
c = Crtsh()
certs = c.search("%.example.com")
for cert in certs:
    print(f"Issuer: {cert.get('issuer_name')}, Domain: {cert.get('name_value')}")
Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 52 lines · 67 tokens per session scan A 29183850644e

Subscribe to this mod's changes

analyzing-tls-certificate-transparency-logs is a skill published in the GitHub repository autohandai/community-skills (11 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 67 tokens to every session and 359 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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analyzing-tls-certificate-transparency-logs

Queries Certificate Transparency logs via crt.sh and pycrtsh to detect phishing domains, unauthorized certificate issuance, and shadow IT. Monitors newly issued certificates for typosquatting and brand impersonation using Levenshtein distance. Use for proactive phishing domain detection and certificate monitoring.

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Queries Certificate Transparency logs via crt.sh and pycrtsh to detect phishing domains, unauthorized certificate issuance, and shadow IT. Monitors newly issued certificates for typosquatting and brand impersonation using Levenshtein distance. Use for proactive phishing domain detection and certificate monitoring.

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