Email Security Best Practices for Small Businesses

Email remains the primary attack vector for cybercriminals targeting small businesses. Over 90% of cyberattacks begin with a malicious email. Here's how to protect your organization.

Why Email Security Matters

Your business email is a gateway to everything—financial accounts, customer data, internal systems, and confidential communications. A single compromised email account can lead to:

• Financial fraud — Attackers redirect payments or steal directly from accounts
• Data breaches — Sensitive customer and business information exposed
• Ransomware infections — Malicious attachments encrypt your entire network
• Reputation damage — Your email used to attack customers and partners
• Compliance violations — HIPAA, PCI-DSS, and other regulations mandate email security

Essential Email Security Measures

1. Enable Multi-Factor Authentication (MFA)

MFA is the single most effective security control for email. Even if an attacker obtains a password, they can't access the account without the second factor. Microsoft reports that MFA blocks 99.9% of account compromise attacks.

Enable MFA on all email accounts immediately. Most email platforms (Microsoft 365, Google Workspace) include this feature at no additional cost.

2. Implement Advanced Email Filtering

Basic spam filters aren't enough against modern threats. Advanced email security solutions provide:

• AI-powered phishing detection
• Attachment sandboxing (safely detonating suspicious files)
• Link protection (scanning URLs at click-time)
• Impersonation protection (detecting spoofed executives)
• Outbound filtering (preventing data exfiltration)

3. Train Your Employees

Technology alone isn't enough. Your team needs to recognize threats that slip through filters. Effective security awareness training includes:

• Regular phishing simulations
• Clear reporting procedures for suspicious emails
• Examples of real attacks (sanitized)
• Updates on new threat tactics

4. Configure Email Authentication

Properly configured email authentication prevents attackers from spoofing your domain. Implement:

• SPF — Specifies which servers can send email for your domain
• DKIM — Cryptographically signs emails to prove authenticity
• DMARC — Tells receiving servers what to do with failed authentication

5. Establish Email Policies

Create and enforce policies around email use:

• Never send sensitive data via unencrypted email
• Verify payment/wire transfer requests via phone
• Don't open unexpected attachments
• Report suspicious emails immediately
• Use company email only for business purposes

Warning Signs of Email Compromise

Watch for these indicators that an account may be compromised:

• Emails you didn't send appearing in Sent folder
• Email rules you didn't create (often forwarding to external addresses)
• Login notifications from unfamiliar locations
• Contacts receiving spam from your address
• Password reset emails you didn't request

What to Do If You're Compromised

1. Change the password immediately from a known-clean device
2. Review and remove unauthorized email rules
3. Check for unauthorized app permissions
4. Notify contacts who may have received malicious emails
5. Review sent emails for sensitive data exposure
6. Contact your IT provider for full security review