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SEO35k · #6112

performing-open-source-intelligence-gathering

Helps your agent collect public information about a target. This is used to better understand the organization before an attack.

What it does

This tool helps gather public information about an organization, such as its domains, employees, and technologies. It's useful for understanding how a target might be attacked.

When to use it

  • ✓When testing a company's security.
  • ✓When investigating a security incident.
  • ✓When planning a security test.

Example of what to ask your AI

“Gather information about the company 'Example Inc.'.”

Want more? Open the sections below.

How to use

The easiest way: copy the message below and paste it into Claude, ChatGPT, Cursor or any AI. It reads the skill and follows the instructions.

Skill link

https://github.com/mukul975/Anthropic-Cybersecurity-Skills/blob/main/skills/performing-open-source-intelligence-gathering/SKILL.md

Ready-to-paste message

Use this skill to help me: https://github.com/mukul975/Anthropic-Cybersecurity-Skills/blob/main/skills/performing-open-source-intelligence-gathering/SKILL.md Read the SKILL.md file at that link and follow its instructions for my task.
How it works

The tool searches for publicly available data from various sources like domain records, social media, and leak databases. It organizes this information to identify weaknesses.

Installation

Easiest way: copy the skill link and paste it into Claude, ChatGPT or Cursor asking it to follow the instructions.

In the terminal (Claude Code, Codex, Cursor), in your project folder:

npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill performing-open-source-intelligence-gathering

Or download just the file:

curl -L https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/main/skills/performing-open-source-intelligence-gathering/SKILL.md -o SKILL.md
Technical content (original SKILL.md)

Original text by the author, straight from GitHub.

Performing Open Source Intelligence Gathering

Legal Notice: This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.

Overview

Open Source Intelligence (OSINT) gathering is the first active phase of a red team engagement, where operators collect publicly available information about the target organization to identify attack surfaces, potential targets for social engineering, technology stacks, and credential exposures. Effective OSINT directly shapes initial access strategies and reduces operational risk.

When to Use

  • When conducting security assessments that involve performing open source intelligence gathering
  • When following incident response procedures for related security events
  • When performing scheduled security testing or auditing activities
  • When validating security controls through hands-on testing

Prerequisites

  • Familiarity with red teaming 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

Objectives

  • Enumerate the target organization's external attack surface (domains, IPs, cloud assets)
  • Identify employees and their roles for social engineering targeting
  • Discover leaked credentials, API keys, and sensitive documents
  • Map the organization's technology stack and vendors
  • Identify physical locations, office layouts, and access control details
  • Build target profiles for spearphishing campaign development

Core Concepts

OSINT Categories

Category Sources Value
Domain Intelligence DNS records, WHOIS, CT logs, subdomain enumeration Network attack surface
Personnel Intelligence LinkedIn, social media, conference talks, publications Social engineering targets
Credential Intelligence Breach databases, paste sites, GitHub leaks Valid credential discovery
Technology Intelligence Job postings, Wappalyzer, Shodan, Censys Vulnerability identification
Physical Intelligence Google Maps, social media photos, Glassdoor Physical access planning
Document Intelligence SEC filings, public documents, metadata extraction Organizational structure

MITRE ATT&CK Mapping

  • T1595.001 - Active Scanning: Scanning IP Blocks
  • T1595.002 - Active Scanning: Vulnerability Scanning
  • T1592 - Gather Victim Host Information
  • T1589 - Gather Victim Identity Information
  • T1590 - Gather Victim Network Information
  • T1591 - Gather Victim Org Information
  • T1593 - Search Open Websites/Domains
  • T1594 - Search Victim-Owned Websites
  • T1596 - Search Open Technical Databases

Workflow

Phase 1: Domain and Network Reconnaissance

  1. Perform WHOIS lookups for target domains
  2. Enumerate subdomains using Certificate Transparency logs, DNS brute-force, and web scraping
  3. Identify IP ranges and ASN ownership
  4. Scan for exposed services using Shodan/Censys
  5. Check for cloud storage buckets (S3, Azure Blob, GCS)
  6. Map CDN and hosting providers

Phase 2: Personnel and Social Intelligence

  1. Enumerate employees via LinkedIn, company website, and conference speaker lists
  2. Identify email naming conventions
  3. Discover personal social media accounts of key targets
  4. Map organizational hierarchy and reporting structure
  5. Identify recently hired IT/security personnel
  6. Check for conference presentations and technical publications

Phase 3: Credential and Data Leak Discovery

  1. Search breach databases (Have I Been Pwned, DeHashed)
  2. Check paste sites (Pastebin, GitHub Gists)
  3. Search GitHub/GitLab for leaked secrets and API keys
  4. Look for exposed configuration files and backups
  5. Check for leaked internal documents via Google dorking

Phase 4: Technology Stack Identification

  1. Analyze job postings for technology mentions
  2. Use Wappalyzer/BuiltWith for web technology fingerprinting
  3. Check for exposed admin panels and development environments
  4. Identify VPN and remote access technologies
  5. Map cloud services and SaaS applications

Tools and Resources

Tool Purpose Type
Amass Subdomain enumeration and network mapping Open Source
Subfinder Passive subdomain discovery Open Source

…

FAQ

What is 'Open Source Intelligence' (OSINT)?

It's collecting information that is already publicly available, without needing to hack into systems.

Do I need permission to use this tool?

Yes, you should only use it on systems you own or have explicit permission to test. Unauthorized use is illegal.

What kind of information does it collect?

It can collect domain names, email addresses, technologies used, potential password leaks, and employee information.

Details

Original description by the author

Open Source Intelligence (OSINT) gathering is the first active phase of a red team engagement, where operators collect publicly available information about the target organization to identify attack s

repo: mukul975/Anthropic-Cybersecurity-Skills

Popularity

GitHub stars
35k
Ranking position
#6112
License
Apache-2.0
Updated
8/31/2026

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