theHarvester

What it does

theHarvester collects emails, names, subdomains, IPs, and URLs from public sources like search engines and certificate transparency logs. Useful for early footprinting of a target organization.

Common use cases

• •Build a target employee directory from public email harvests for social engineering.
• •Discover subdomains and IP ranges without ever touching the target's infrastructure.
• •Cross-reference leaked credentials against harvested emails in a password-spray test.

Key features

• •Queries search engines, CT logs, and APIs from a single tool.
• •Harvests emails, subdomains, hosts, and virtual hosts in one pass.
• •Results exportable to HTML, JSON, XML, and plain text formats.

Source