10 Email Security Best Practices Every Organization Should Follow in 2025

Email is still the favorite entry point for attackers. Phishing, credential theft, malicious attachments — the methods keep evolving, but the channel remains the same. While most companies already use filtering tools, that alone isn’t enough. Strong security depends on combining technology with disciplined user behavior.

Here are ten best practices that matter most today.

Train employees, repeatedly

Awareness is the first line of defense. Regular sessions help staff recognize phishing attempts, suspicious attachments, and fake login pages. Security awareness isn’t a one-time onboarding slide deck — it’s continuous practice.

Strong, unique passwords

Forget cryptic strings nobody remembers. Longer passphrases built from random words are stronger and easier to use. Just as important: no password reuse. A single leaked credential can unlock multiple accounts if reused across systems.

Multifactor authentication everywhere

MFA is no longer optional. A second factor — whether an authenticator app, hardware token, or biometric — drastically reduces account takeover risks. Enterprises should enforce MFA for all email accounts, including external contractors.

Take phishing seriously

Filters catch a lot, but not everything. Staff must treat every unexpected link or attachment with suspicion, especially those urging quick action. Many organizations run phishing simulations to train and measure readiness.

Limit where email can be accessed

Company mail should only be opened on managed, trusted devices. BYOD without controls is still a major leak vector. Device management and conditional access policies reduce exposure from compromised laptops and phones.

Encrypt messages and attachments

Unencrypted email is basically a postcard. Encryption should cover not just the message, but also the connection to the provider and the attachments themselves. This protects against interception and reduces exposure in case of leaks.

Avoid public Wi-Fi for corporate email

Open Wi-Fi networks are hunting grounds for attackers. Even if traffic is encrypted, metadata and credentials can still be exposed. VPNs or mobile hotspots are safer alternatives when outside the office.

Use modern email authentication protocols

Standards like SPF, DKIM, and DMARC help prevent spoofing and impersonation. Without them, attackers can forge domains and trick users with convincing phishing emails. These should be mandatory in every enterprise mail setup.

Layer with dedicated security tools

Relying only on the provider’s built-in protections is risky. Email gateways, advanced filtering, sandboxing for attachments, and endpoint security should all be part of the mix. Defense in depth is key.

Don’t stay logged in

It sounds trivial, but leaving accounts open on shared or unattended devices is still a real problem. Logging out — especially on mobile and public systems — closes off one of the simplest but most overlooked attack paths.

Email will remain a high-risk channel, no matter how much technology evolves. The only way to keep it under control is to combine strict technical safeguards with consistent user discipline. Companies that treat email security as an ongoing process, not a one-time project, will always have the upper hand.