Business Email Security: The Controls That Matter Most

Email remains one of the main places attackers meet staff, so protecting it requires more than spam filtering. The strongest setup combines identity controls, message protection, domain authentication, monitoring and staff process.

Protect the account first

Require MFA, strengthen privileged accounts and use Conditional Access appropriately. If the mailbox account itself is taken over, even perfect inbound filtering cannot help.

Use modern mail protection

Filter malicious links, attachments, impersonation and known threats, and make sure somebody can investigate suspicious messages rather than relying entirely on automated scoring.

Configure SPF, DKIM and DMARC

These controls help receiving mail systems verify whether a message claiming to come from your domain is authorised. DMARC also gives the domain owner a policy and reporting mechanism rather than leaving spoofing behaviour entirely to recipients.

Review forwarding and inbox rules

Unexpected forwarding and attacker-created mailbox rules are common ways to hide activity or move information out of the business. Review them both routinely and during incident response.

Give staff an easy reporting path

If a message looks suspicious, staff should know how to report it without forwarding the threat around internally or worrying that they will be blamed for asking.

Watch for business-process fraud

Email can be technically genuine and still be dangerous when an attacker controls a real supplier or colleague mailbox. Payment changes, bank-account changes and urgent confidential requests should have an out-of-band verification process.

That last problem is Business Email Compromise, which deserves its own guide because the control is as much about business process as email technology. For the wider setup, use the Security Self-Check.