What Is Phishing? How to Protect Corporate Email

More than 90% of phishing attacks start over email. Common tactics, employee awareness, and protection through mail filtering.

June 18, 2026 · 6 min read

Phishing is a social engineering technique where attackers pose as a trusted organization or person to trick users. The goal is usually to steal a username and password, get a malicious file executed, or trigger a direct money transfer. The majority of security breaches still start with a phishing email, because even the strongest firewall can't always stop an employee from clicking a fake link.

Common Phishing Tactics

• Fake invoice / shipping notice: emails titled "Your payment is overdue" or "Your package couldn't be delivered," carrying a malicious attachment
• CEO fraud (Business Email Compromise): impersonating a senior executive to request an urgent wire transfer from accounting
• Credential theft: fake login pages that look identical to Microsoft 365, a bank, or a cloud service
• Spear phishing: targeted attacks built with information gathered from LinkedIn or a company website, tailored to one specific person
• QR code phishing (quishing): a QR code in an email or on paper that redirects a mobile device to a fake site

How to Spot a Fake Email

1. Check the sender's address carefully: even if the display name looks right, the actual email address often contains a suspicious domain.
2. Be suspicious of urgency and pressure: phrases like "your account will be closed if you don't act now" are a classic manipulation tactic.
3. Hover over links before clicking to see the real destination: hovering the mouse over a link on desktop reveals the actual URL.
4. Don't open unexpected attachments: .zip, .exe, and macro-enabled Office files carry especially high risk.
5. Verify through a second channel: confirm by phone any email requesting a payment or a change to bank details.

Attackers can now use AI-assisted tools to produce grammatically correct, professionally worded emails. "Watch for badly written emails" is no longer a sufficient defense on its own.

Protection at the Organizational Level

Employee awareness is an important layer, but it needs to be backed by technical controls:

• Advanced mail filtering: detects malicious attachments, links, and spoofed sender addresses (including DMARC/SPF/DKIM validation)
• Time-of-click URL protection: re-checks a link's safety at the moment the user clicks it
• Multi-factor authentication (MFA): makes it harder to take over an account even if the password is stolen
• Simulation and training: measures and improves employee awareness through regular phishing drills

Trend Micro Worry-Free Business Security and TrendAI Vision One™ stop most phishing emails before they reach the user, using behavioral analysis and URL reputation checks at the mail gateway level. Get in touch with us to assess the right mail security configuration for your organization.