Recon Osint

Skill: Recon & OSINT

Supplementary Files:

• payloads.md — Complete command set categorized by Passive Recon, Active Scanning, Subdomain Enumeration, Technology Fingerprinting, Email Harvesting, Social Media OSINT, Metadata Extraction, and Google Dorks
• test-cases.md — 11 structured test cases covering passive reconnaissance, active scanning, OSINT collection, and technology fingerprinting, with severity levels and verification criteria

Summary

Information gathering determines the precision and efficiency of subsequent attacks.

Domain: osint

MITRE ATT&CK: TA0043-Reconnaissance

Description

The most critical first step in penetration testing. Information gathering determines the precision and efficiency of subsequent attacks. This skill covers three major areas: passive reconnaissance (OSINT), active reconnaissance (port scanning, service identification), and web fingerprinting — from domain enumeration to directory bruteforcing, building a complete target profile. Mastered tools include nmap, dig, whois, whatweb, wpscan, gobuster, theHarvester, sublist3r, assetfinder, dirb, zenmap, as well as tools currently being learned: maltego, photon, recon-ng, ffuf, dnsenum, fierce, etc.

Use Cases

• Pre-engagement reconnaissance for penetration testing: comprehensive information gathering on the target, mapping the attack surface
• Red team exercise asset discovery: enumerating subdomains, IP ranges, open services, finding weak entry points
• Security assessment and compliance audits: identifying exposed surfaces, unauthorized services, information leakage
• CTF competition information gathering phase: rapidly locating target services and attack paths
• Threat intelligence tracking: collecting information about the target organization's personnel, emails, and technology stack

Core Tools

Methodology

Attack Chain

Step 1: Passive Recon

No direct interaction with the target, minimizing exposure risk. Collect domain registration information, DNS records, search engine caches, and social media data.

Step 2: Subdomain and Asset Discovery

Enumerate all subdomains and associated assets to expand the attack surface. Cross-validate with multiple tools to avoid missing targets.

Step 3: Active Scanning and Service Identification

Perform port scanning and service version identification on discovered assets, building a service inventory.

Step 4: Web Application Fingerprinting and Directory Enumeration

Identify web technology stacks, CMS, and framework versions; bruteforce hidden directories and files.

Step 5: OSINT Deep Correlation Analysis

Cross-correlate collected information and build a complete attack surface map.

Defense Perspective

• Restrict DNS Zone Transfers: Configure DNS servers to reject unauthorized AXFR requests
• Minimize Information Leakage: Disable web server version display, remove default pages
• Monitor Reconnaissance Activity: Deploy IDS/IPS to detect abnormal scanning patterns, log whois and DNS queries
• CDN and WAF Deployment: Hide real IPs, block automated scanning tools
• Subdomain Takeover Prevention: Regularly check DNS record pointers, clean up stale CNAME records
• OSINT Protection Awareness: Minimize employee social media exposure, avoid leaking technology stack details on public platforms

Practical Steps

Detailed payloads in payloads.md, complete test checklist in test-cases.md.

Exercise 1: Full Domain Reconnaissance Workflow

1. Basic domain information lookup (whois + dig)
2. Multi-tool subdomain enumeration with cross-validation (sublist3r + assetfinder + dnsenum)
3. Merge, deduplicate, and verify liveness (sort + httpx)

Exercise 2: Target Network Port Scanning

1. Rapid live host discovery (nmap -sn)
2. Full port deep scan (nmap -sS -sV -sC -O -p-)
3. Visual analysis (zenmap)

Exercise 3: Web Application Deep Scanning

1. Technology stack identification (whatweb)
2. CMS-specific scanning (wpscan)
3. Dual-tool directory bruteforce verification (dirb + gobuster)

Exercise 4: Deep Crawling and Correlation Analysis

1. Comprehensive target website crawling (photon)
2. Automated information correlation (recon-ng)
3. Visual correlation analysis (maltego)

Detection Methods

Reconnaissance Detection

• Subdomain enumeration: Spike in DNS queries for non-existent subdomains (DNS brute force signature).
• Certificate Transparency monitoring: New certificates issued for typosquatted or subdomains of your brand.
• Search engine dorking: site:yourdomain.com filetype:pdf inurl:admin queries in Google Search Console.
• WHOIS lookups: Spike in WHOIS queries from non-trusted resolvers.

SIEM Detection Rules

• Splunk SPL: index=dns query="*.yourdomain.com" | stats count by src_ip | where count > 100
• crt.sh / CertSpotter: Certificate Transparency alerting on new certs for your brand.
• Shodan / Censys monitoring: Regular export of your org's exposed services.

Defense Evasion Techniques

Stealth Reconnaissance

• Passive over active: Prefer crt.sh (CT logs) over nmap; no packets hit target.
• Rate limiting: Cap queries below detection threshold.
• Distributed source IPs: Use residential proxies for active recon.
• Off-hours timing: Active scans during target's off-hours.
• Source port spoofing: Use --source-port 53 to look like DNS; bypasses some firewalls.

Search Engine Dorking Stealth

• Multi-engine: Distribute dorking across Google, Bing, DuckDuckGo, Yandex.
• Natural language queries: Avoid obvious inurl:admin; use natural language.
• Cached content access: Use cache: operator or archive.org; no traffic to target.
• Search Console manipulation: Use scripted Google searches via legitimate API; evade anti-bot.

Code Repository Recon Stealth

• GitHub API over search: Use api.github.com/search/code (rate-limited but less suspicious).
• Fork before analyze: Fork target repo privately; avoid revealing interest via clones.
• TruffleHog locally: Run secret scanners locally; don't upload to third-party services.

Hacker Laws

• First Principles Thinking: Don't blindly rely on tool output. Understand the principles behind DNS queries, TCP handshake mechanisms, and HTTP protocol details. Tools are merely execution mechanisms; principles are the foundation for discovering vulnerabilities.
• Divergent Thinking First: Subdomain enumeration is not limited to one approach — search engines, certificate transparency, DNS bruteforcing, crawler extraction, and OSINT correlation. Use at least 3 methods for cross-validation to avoid single-source blind spots.
• Trust but Verify: Scan results require verification. Ports reported by nmap may be interfered with by firewalls, whois data may be outdated, and subdomains may be offline. Every finding must be confirmed a second time.
• Minimize Attack Surface: From a defensive perspective, every exposed port, DNS record, and directory is a potential entry point. Understanding the attack surface during reconnaissance is essential for effectively narrowing it.

Learning Resources

Tool Memory Files (memory/)

• memory/photon.md - Photon crawler usage guide and option details
• memory/dirb.md - Dirb directory scanner configuration and practical examples
• memory/dnsenum.md - Dnsenum DNS enumeration tool usage
• memory/fierce.md - Fierce subdomain scanning and DNS analysis
• memory/maltego.md - Maltego visual OSINT analysis workflow
• memory/legion.md - Legion semi-automated penetration testing framework
• memory/recon-ng.md - Recon-ng modular reconnaissance framework guide
• memory/caido.md - Caido web proxy tool
• memory/hping3.md - Hping3 advanced network probing tool

Reference Guides (guides/)

• guides/api_security_complete_guide.md - API security assessment guide
• guides/security_misconfiguration_complete_guide.md - Security misconfiguration identification
• guides/insecure_design_complete_guide.md - Insecure design pattern identification

Core System Files

• SOUL.md - Complete hacker laws definition
• TOOLS.md - Tool ecosystem overview

This skill's supplementary files: payloads.md, test-cases.md Related skills: skills/network-pentest/SKILL.md, skills/social-engineering/SKILL.md External resources:

• OWASP Information Gathering
• SANS OSINT Poster
• Nmap Documentation