analyzing-certificate-transparency-for-phishing

analyzing-certificate-transparency-for-phishing is a skill for Claude Code from oyi77/1ai-skills. It costs 56 tokens per session (3,444 once invoked), scanned A, original, MIT.

A security analysis guide for monitoring Certificate Transparency logs, public records of issued SSL/TLS certificates. It uses these records to find suspicious domains and certificates that imitate an organisation.

In plain words
What is it for?
It helps monitor for lookalike domains, investigate suspicious certificate issuance, and feed findings into threat-intelligence alerts.
Why use it?
It can reveal phishing infrastructure or unauthorised certificates before they are used in an attack.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the 1ai-skills plugin — 209 skills, 4 commands shipped together

Good fit It helps monitor for lookalike domains, investigate suspicious certificate issuance, and feed findings into threat-intelligence alerts.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/oyi77/1ai-skills/analyzing-certificate-transparency-for-phishing
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 oyi77/1ai-skills --skill analyzing-certificate-transparency-for-phishing
Clone the repo
git clone --depth 1 https://github.com/oyi77/1ai-skills

Made for: Claude Code.

Or install 1ai-skills, the plugin that ships this one along with the rest of its 209 skills, 4 commands.

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-certificate-transparency-for-phishing

README.md
[![agentmods](https://agentmods.dev/badge/skills/oyi77/1ai-skills/analyzing-certificate-transparency-for-phishing/github.svg)](https://agentmods.dev/skills/oyi77/1ai-skills/analyzing-certificate-transparency-for-phishing)
Your own site
<a href="https://agentmods.dev/skills/oyi77/1ai-skills/analyzing-certificate-transparency-for-phishing"><img src="https://agentmods.dev/badge/skills/oyi77/1ai-skills/analyzing-certificate-transparency-for-phishing/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-certificate-transparency-for-phishing

Your own site · 80×15
<a href="https://agentmods.dev/skills/oyi77/1ai-skills/analyzing-certificate-transparency-for-phishing"><img src="https://agentmods.dev/badge/skills/oyi77/1ai-skills/analyzing-certificate-transparency-for-phishing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,444 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00056 $0.03444
Opus 5 $0.00028 $0.01722
Sonnet 5 $0.00011 $0.00689
Haiku 4.5 $0.00006 $0.00344

Measured 8d ago against content hash 4b5d66749250, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

analyzing-certificate-transparency-for-phishing scanned grade A with 1 finding 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 8d ago.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

resp = requests.get(self.CRT_SH_URL, params=params, timeout=30)
cybersecurity/analyzing-certificate-transparency-for-phishing/SKILL.md · 406 lines

How it starts

The opening of the file, as written. The whole thing — 406 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Analyzing Certificate Transparency for Phishing

Overview

Certificate Transparency (CT) is an Internet security standard that creates a public, append-only log of all issued SSL/TLS certificates. Monitoring CT logs enables early detection of phishing domains that register certificates mimicking legitimate brands, unauthorized certificate issuance for owned domains, and certificate-based attack infrastructure. This skill covers querying CT logs via crt.sh, real-time monitoring with Certstream, building automated alerting for suspicious certificates, and integrating findings into threat intelligence workflows.

When to Use

Trigger phrases:

  • "analyzing certificate transparency for phishing"

  • "Monitor Certificate Transparency logs using crt"

  • When investigating security incidents that require analyzing certificate transparency for phishing

  • When building detection rules or threat hunting queries for this domain

  • When SOC analysts need structured procedures for this analysis type

  • When validating security monitoring coverage for related attack techniques

Prerequisites

  • Python 3.9+ with requests, certstream, tldextract, Levenshtein libraries
  • Access to crt.sh (https://crt.sh/) for historical CT log queries
  • Certstream (https://certstream.calidog.io/) for real-time monitoring
  • List of organization domains and brand keywords to monitor
  • Understanding of SSL/TLS certificate structure and issuance process

Key Concepts

This section covers key concepts for analyzing certificate transparency for phishing.

  • Ensure all prerequisites are met before proceeding
  • Follow the documented workflow steps in sequence
  • Record results and any anomalies encountered during this phase

Certificate Transparency Logs

CT logs are cryptographically assured, publicly auditable, append-only records of TLS certificate issuance. Major CAs (Let's Encrypt, DigiCert, Sectigo, Google Trust Services) submit all issued certificates to multiple CT logs. As of 2025, Chrome and Safari require CT for all publicly trusted certificates.

Read the full file on GitHub · 406 lines

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. 8d ago First seen · 406 lines · 56 tokens per session scan A 4b5d66749250

Subscribe to this mod's changes

analyzing-certificate-transparency-for-phishing is a skill published in the GitHub repository oyi77/1ai-skills (12 stars, last pushed today), licensed MIT. It adds 56 tokens to every session and 3,444 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-04.

Related

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