theHarvester – OSINT Tool for Gathering Emails, Subdomains, and More

theHarvester is an OSINT (Open Source Intelligence) tool used to collect publicly available information about a target domain. It helps gather:

• Email addresses

• Subdomains

• IP addresses

• Hostnames

• Open ports (via Shodan or Censys)

• Banners and metadata

This tool is commonly used during the reconnaissance phase of penetration testing, red teaming, or bug bounty hunting.

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⚙️ How theHarvester Works

It gathers data from public sources using both passive and active reconnaissance.

Passive:

No direct interaction with the target — pulls data from:

• Bing, DuckDuckGo, Baidu, Brave

• crt.sh (certificate transparency logs)

• Hunter.io, GitHub

• Public repositories

Active:

May touch the target using:

• Shodan (for open ports and banners)

• Censys

• DNS brute-forcing (optional)

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🛠️ Installation

On Kali Linux:

Already installed. Just run:

theharvester -h

Manual Setup:

git clone https://github.com/laramies/theHarvester.git
cd theHarvester
python3 -m venv venv
source venv/bin/activate
pip install -r requirements/base.txt

API keys for Shodan, Hunter.io, etc. should be placed inside:

api-keys.yaml

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🧪 Usage Examples

Basic:

python3 theHarvester.py -d example.com -b bing

Full Recon with All Sources:

python3 theHarvester.py -d example.com -b all -l 100 -f report.html -v

Options Breakdown:

• -d → Target domain

• -b → Source (e.g., bing, google, baidu, etc.)

• -l → Limit number of results (e.g., -l 100)

• -f → Save output to file (e.g., -f result.html)

• -v → Verbose mode

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📁 Output Formats

theHarvester supports:

• .html for human-readable reports

• .json, .xml for automation

• .csv for Excel analysis

Example:

-f output.html

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🔐 Ethical Use

Use only on targets you’re authorized to test. This tool is meant for:

• Penetration testing (with permission)

• Red teaming

• Educational purposes

• Bug bounty recon

Unauthorized scanning = illegal activity.

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📚 Resources

• GitHub: https://github.com/laramies/theHarvester

• YouTube Tutorial: Watch Here