Email Address Discovery: No Server Access Needed

TL;DR

Yes, attackers can discover email addresses without getting into your server. They use techniques like scraping websites, social media searches, and guessing common formats. Protecting yourself involves limiting public information, using strong email security measures, and monitoring for leaks.

How Attackers Find Email Addresses (Without Server Access)

1. Website Scraping: Attackers use automated tools to scan your website for email addresses. This includes pages like ‘Contact Us’, ‘About Us’, legal notices, and even blog posts.
   • What it looks like: A script systematically visits each page of your site looking for patterns like @yourdomain.com.
   • Prevention: Don’t publish email addresses directly on your website. Use contact forms instead.
2. Social Media Searches: Platforms like LinkedIn, Twitter, and Facebook often contain publicly visible email addresses.
   • What it looks like: Searching profiles for keywords related to your company or employees combined with ‘@yourdomain.com’.
   • Prevention: Review privacy settings on social media accounts. Encourage employees to be mindful of what they share.
3. Email Guessing/Brute-Force: Attackers try common email address formats (e.g., [email protected], [email protected], [email protected]).
   • What it looks like: Using tools to send emails to a list of potential addresses and seeing which ones don’t bounce.
   • Prevention: Use email security solutions that can detect and block these attempts (see step 6).
4. Data Breaches & Leaks: Past data breaches involving your company or related services might expose email addresses.
   • What it looks like: Email addresses appearing on websites like ‘Have I Been Pwned?’ (https://haveibeenpwned.com/).
   • Prevention: Regularly check for data breaches and notify users if their information is compromised. Use strong passwords and multi-factor authentication.
5. WHOIS Lookup: While less common now due to privacy protections, WHOIS records sometimes contain administrative contact email addresses.
   • What it looks like: Using a WHOIS tool to find the registered owner’s contact information for your domain.
   • Prevention: Use privacy protection services when registering your domain.

Protecting Your Email Addresses

6. Use Contact Forms: Replace direct email addresses on your website with contact forms. This prevents scraping.
   • Example (HTML):

     <form action="/submit-contact" method="post"> 
       <label for="name">Name:</label>
       <input type="text" id="name" name="name" required><br>
       <label for="email">Email:</label>
       <input type="email" id="email" name="email" required><br>
       <button type="submit">Send Message</button>
     </form>

7. Email Address Obfuscation: If you *must* display an email address, use techniques to make it harder for bots to read.
   • Example (HTML): ainfo@yourdomain.com
8. Email Security Solutions: Implement solutions that filter spam and block malicious emails.
   • Examples: SpamAssassin, Microsoft Defender for Office 365, Google Workspace security features.
9. Monitor for Leaks: Regularly search online for your company’s email addresses to identify potential leaks.
   • Tools: Google Alerts, specialized monitoring services.
10. DMARC, SPF & DKIM: Implement these email authentication protocols to prevent spoofing and phishing attacks.
    • What they do: Verify that emails are legitimately sent from your domain.