Email Security Guide: How to Identify Phishing and Protect Your Business

Email security and phishing protection for businesses

Email remains the #1 attack vector for cybercriminals. Phishing, business email compromise (BEC), and ransomware delivery all arrive through your inbox. This guide from Atlantic Computer Systems helps you identify threats, manage spam, and configure your email for maximum security. For broader security practices, also read our Cybersecurity Best Practices Guide.

How to Identify Phishing Emails

Check sender addresses carefully — attackers use domains like “microsoft-support.com” instead of “microsoft.com.” Watch for urgent language, generic greetings, hover-check all links, and be cautious of unexpected attachments (especially .zip, macro-enabled Office docs, or .exe files). Our managed cybersecurity services include advanced email filtering, but human awareness is your last line of defense.

Business Email Compromise (BEC)

BEC attacks impersonate executives or vendors to trick employees into wire transfers or sharing sensitive data. Always verify money transfer requests or payment detail changes through a separate phone call. Industries like finance and legal are particularly targeted.

Managing Spam & Quarantine

Microsoft 365 quarantine: access at security.microsoft.com. Check regularly — legitimate emails can be flagged. Use the Report Message button in Outlook to improve filtering for your whole organization. Our IT management team can configure advanced anti-spam policies.

Configuring Outlook Securely

Enable external sender tags, disable automatic image loading (blocks tracking pixels), and set junk filter to High. For sending: use Microsoft 365 encryption for sensitive data, avoid sensitive info in subject lines, and double-check autocomplete recipients.

If You Click a Suspicious Link

Disconnect from the network. Change your password from a different device. Run a full antivirus scan. Report immediately to ACS at 1-650-300-7557 or through our Client Support Hub. Don’t delete the email — we may need it for investigation. For new employees learning these practices, see our New Employee IT Setup Guide. Contact us for a security assessment or view our pricing.

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