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Email Discovery Techniques

Email discovery is a crucial component of OSINT investigations. This guide covers tools and techniques for finding and verifying email addresses.

Email Discovery Tools

Primary Discovery Platforms

Hunter.io

  • Type: Professional email finder and verifier
  • Key Features:
  • Domain-based email discovery
  • Department-specific email search functionality
  • Email verification and deliverability scoring
  • Bulk email discovery for organizations
  • Chrome extension for real-time searches
  • Pricing: Freemium (limited searches), paid plans available
  • Best for: Corporate email discovery and verification

Phonebook.cz

  • Type: Comprehensive contact information database
  • Key Features:
  • Email, phone, and domain searches
  • Historical data tracking
  • API access available
  • Multiple data sources
  • Alternative: IntelX for broader search capabilities
  • Best for: Historical email data and comprehensive searches

VoilaNorbert

  • Type: Email finder with high accuracy rates
  • Key Features:
  • Specializes in finding professional email addresses
  • Real-time email verification
  • Bulk processing capabilities
  • CRM integrations
  • Accuracy: Claims 98% accuracy rate
  • Best for: Sales and marketing email discovery

Clearbit Connect

  • Type: Email discovery and enrichment platform
  • Key Features:
  • Gmail integration
  • Additional contact information and company data
  • Social media profile linking
  • Automated email sequences
  • Best for: Gmail users and comprehensive contact enrichment

VerifyMail.io

  • Type: Email address verification service
  • Key Features:
  • Real-time email validation
  • Bulk verification capabilities
  • API integration
  • Detailed verification reports
  • Best for: Validating discovered email addresses

Free Discovery Methods

Search Engine Techniques

Google-Based Discovery
"john smith" "@company.com"
site:company.com "email" OR "contact"
site:company.com filetype:pdf "john smith"
"john smith" "email:" OR "e-mail:"
Advanced Search Combinations
site:linkedin.com "john smith" "email"
site:company.com "contact us" email
"john smith" filetype:pdf site:company.com
Document Mining
site:company.com filetype:pdf "email" OR "contact"
site:company.com filetype:doc "directory"
"employee directory" site:company.com

Social Media Mining

LinkedIn Searches
site:linkedin.com "john smith" "company name"
site:linkedin.com "email" "john smith"
Twitter Discovery
site:twitter.com "john smith" "email"
site:twitter.com "@company" "contact"

Email Pattern Recognition

Common Corporate Patterns
  • firstname.lastname@company.com
  • first.last@company.com
  • f.lastname@company.com
  • firstnamelastname@company.com
  • firstname@company.com
Testing Patterns

Once you identify one email format, test variations: - If john.smith@company.com exists, try jane.doe@company.com - Use employee directories to test patterns - Verify through password recovery systems

Email Verification Techniques

Technical Verification

SMTP Verification

telnet mail.company.com 25
HELO your-domain.com
MAIL FROM: test@your-domain.com
RCPT TO: target@company.com

MX Record Lookup

nslookup -type=mx company.com
dig mx company.com

Online Verification Tools

Free Verification Services

Verification Indicators

  • Valid: Email exists and accepts mail
  • Invalid: Email doesn't exist
  • Risky: Catch-all or unknown status
  • Unknown: Cannot determine status

Password Recovery Method

Technique Overview

Many websites reveal partial email addresses during password recovery processes.

Step-by-Step Process

  1. Navigate to Target Website
  2. Find the login page

  3. Locate "Forgot Password" or "Reset Password" link

  4. Attempt Recovery

  5. Enter suspected email variations
  6. Note any partial reveals in error messages

  7. Document patterns observed

  8. Pattern Analysis

  9. Use revealed information to confirm email patterns
  10. Test additional variations based on discoveries
  11. Cross-reference with known employee names

Example Scenarios

Scenario 1: Partial Reveal

  • Input: j.smith@company.com
  • Response: "If j.s***@company.com exists, you'll receive a reset email"
  • Confirmed: Email exists with j.s pattern

Scenario 2: Error Messages

  • Input: invalid@company.com
  • Response: "Email not found"
  • Input: john.smith@company.com
  • Response: "Reset link sent"
  • Confirmed: Email exists

Advanced Discovery Techniques

GitHub Email Mining

Repository Searches

user:username email
author-email:target@company.com
committer-email:target@company.com

Commit History Analysis

git log --format='%ae' | sort | uniq
git shortlog -sne

Domain Intelligence

WHOIS Lookups

whois company.com
whois -h whois.arin.net company.com

Certificate Transparency Logs

Breach Database Searches

Public Breach Databases

Search Techniques

  • Domain-based searches
  • Name-based correlations
  • Historical breach analysis

Email Intelligence Analysis

Metadata Extraction

Email Header Analysis

  • Received: Server path and timestamps
  • X-Originating-IP: Sender's IP address
  • Message-ID: Unique identifier patterns
  • User-Agent: Email client information

Tools for Analysis

Domain Correlation

site:*.company.com
related:company.com
"company.com" -site:company.com

Infrastructure Analysis

  • Mail servers (MX records)
  • SPF/DKIM records
  • Subdomains and related properties

Best Practices and Ethics

Compliance Requirements

  • Respect platform Terms of Service
  • Follow data protection regulations (GDPR, CCPA)
  • Ensure legitimate business purpose
  • Maintain evidence documentation

Ethical Guidelines

  • Use information responsibly
  • Protect privacy of uninvolved individuals
  • Avoid harassment or stalking
  • Respect opt-out requests

Data Protection

Secure Storage

  • Encrypt sensitive email lists
  • Implement access controls
  • Regular security audits
  • Secure disposal of outdated data

Documentation Standards

  • Source attribution for all discoveries
  • Timestamp all searches
  • Method documentation
  • Confidence level assessment

Common Pitfalls and Solutions

False Positives

  • Issue: Invalid emails appearing valid
  • Solution: Use multiple verification methods

Rate Limiting

  • Issue: Search tools blocking requests
  • Solution: Use multiple tools, respect limits

Outdated Information

  • Issue: Emails no longer active
  • Solution: Verify recency and cross-check sources
  • Issue: Violating terms of service
  • Solution: Review platform policies, use legitimate methods

Integration with Other OSINT Techniques

Social Media Correlation

  • Link discovered emails to social profiles
  • Verify through profile contact information
  • Cross-reference across platforms

Phone Number Correlation

  • Use services that provide both email and phone
  • Verify through contact forms
  • Check business directories

Domain Investigation

  • Analyze company infrastructure
  • Identify related domains and subdomains
  • Map organizational structure

Automation and Scripting

Python Libraries

import requests
from email_validator import validate_email
import dns.resolver

Bash Scripts

#!/bin/bash
# Basic email pattern tester
domain="company.com"
names=("john.smith" "jane.doe" "mike.jones")
for name in "${names[@]}"; do
    echo "Testing: ${name}@${domain}"
done

API Integration

  • Hunter.io API
  • Clearbit API
  • Custom verification scripts

Remember: Always use these techniques responsibly and in compliance with applicable laws and regulations.