analyzing-tls-certificate-transparency-logs

name	analyzing-tls-certificate-transparency-logs
description	Use when querying 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.
domain	cybersecurity
tags	["analyzing","tls","certificate","transparency"]
subdomain	security-operations
version	1.0
author	oyi77
license	Apache-2.0
atlas_techniques	["AML.T0073","AML.T0052"]
nist_csf	["DE.CM-01","RS.MA-01","GV.OV-01","DE.AE-02"]

Analyzing Tls Certificate Transparency Logs

Overview

Cybersecurity skill for analyzing tls certificate transparency logs. Follows industry best practices and security standards.

When to Use

Trigger phrases:

• "analyzing tls certificate transparency logs"

• "Queries Certificate Transparency logs via crt"

• When investigating security incidents that require analyzing tls certificate transparency logs

• 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

When NOT to Use

• When you lack proper authorization for testing
• For production systems without change management
• When the task requires legal or compliance expertise beyond technical scope

Prerequisites

• Familiarity with security operations concepts and tools
• Access to a test or lab environment for safe execution
• Python 3.8+ with required dependencies installed
• Appropriate authorization for any testing activities

Workflow

# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}

1. Scope the Analysis — Define what tls certificate transparency logs artifacts or data sources to examine and the investigation timeline.
2. Preserve Evidence — Create forensic copies of relevant data. Maintain chain of custody documentation.