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Implementing the Right Email Security Practices for Modern Threats
Business emails are the prime target for cyberattackers and the email clients we use every day often become the first line of vulnerability.
As per the Phishing Trends Report 2025, 64% of global businesses report facing Business Email Compromise with a typical financial loss averaging $150,000 per incident.
Securing your email client is important, but it’s just one part of a larger strategy. In most cases, attackers pose as trusted contacts and target employees with access to financial systems to trick them into sending money or sharing sensitive information.
To truly protect your communications, verifying the sender’s identity (who the email is from) and ensuring receiver integrity (the message reaches the right person unaltered) is critical.
In this guide, let’s explore the 7 email security best practices to help your business stay protected, improve deliverability, and earn trust in every inbox.
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Choose a Secure and Updated Email Client
A secure email client offers features like end-to-end encryption and zero-access encryption so that only you can read your emails, not even the provider.
On the contrary, poorly secured email client can leave gaps that attackers exploit to intercept messages, inject malicious content, or steal login credentials. So your first line of defense should be a reliable, actively maintained email client.
Here’s what to look for:
- Regular Security Updates: Make sure the email app gets frequent updates that fix security bugs and protect against the latest types of cyberattacks.
- Encryption Support: Look for built-in support for message encryption so your emails are protected from being read or tampered with during transit.
- Transparent Privacy Practices: Some software quietly shares usage data or includes trackers. Choose platforms that clearly outline how your information is handled.
Popular options like Outlook and Apple Mail offer a good balance of usability and enterprise-grade security. But if your team values greater control, open-source clients like Thunderbird lets you customize your security settings.
While almost all popular clients include security features, some of them tend to be more secure than others. So before you choose your email client, visit the websites of different clients and compare their security features together to figure out which ones provide the best security features. You can also read online reviews to learn more about the security part of various email clients.
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Authenticate Your Domain with SPF, DKIM & DMARC
To stop attackers from impersonating your domain, setting up three key authentication protocols in your DNS is non-negotiable: SPF, DKIM, and DMARC.
- SPF – Sender Policy Framework informs receiving mail servers about which IP addresses are permitted to send emails on behalf of your domain. It helps block spoofed messages and reduces the chances of your emails landing in spam.
- DKIM – DomainKeys Identified Mail adds a digital signature to your messages. This confirms the email was actually sent from your domain and wasn’t tampered with on the way.
- DMARC – Domain-based Message Authentication, Reporting & Conformance brings it all together. It lets you decide what should happen when an email fails SPF or DKIM – whether to monitor it, send it to spam, or block it completely.
DMARC policies you can set:
- p=none (monitor activity)
- p=quarantine (send to spam)
- p=reject (block the message)
Having a strict DMARC policy (like p=quarantine or p=reject) not only prevents spoofing but also improves your deliverability and unlocks BIMI. It lets you display your official brand logo in inboxes, which can improve open rates.
SSL2BUY offers free DMARC setup support to help secure your domain and prepare for advanced email authentication. -
Implement BIMI to Build Visual Brand Trust
BIMI (Brand Indicators for Message Identification) allows your company’s official logo to appear next to emails in supported inboxes. It’s a simple but powerful way to build immediate recognition and trust with recipients before they even open your message.
To enable BIMI, here’s what you’ll need in place:
- A valid SPF and DKIM record, plus a DMARC policy set to quarantine or reject
- A BIMI-compliant SVG logo so that it displays cleanly across email clients and devices
- A Verified Mark Certificate (VMC) that proves your trademarked logo belongs to your brand
- A BIMI DNS record pointing to your logo and VMC file
Once everything is set up, your logo will show up in participating inboxes (like Gmail and Apple Mail), giving your emails a visually verified identity and making your messages look instantly trustworthy.
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Upgrade to a Verified Mark Certificate (VMC) for Logo Display
A Verified Mark Certificate is a digital certificate that proves you legally own the logo displayed next to your emails via BIMI. Without a VMC, inboxes like Gmail and Apple Mail (for Gmail accounts) won’t show your logo even if BIMI is configured correctly.
Here are the steps to get the VMC.
- Register your logo with an official trademark office like USPTO or WIPO.
- Once this is done, enforce DMARC with the policy set to either p=quarantine or p=reject.
- Select a reputable authority like DigiCert to buy VMC. After payment, you’ll go through identity verification, including a live video call, ID check, and proof of trademark ownership.
Once approved, you’ll receive a VMC file. You’ll need to host it on your domain and link to it in your BIMI DNS record allowing your brand logo to appear in supported email clients. That’s what makes your verified logo show up in supported inboxes, helping you stand out and build immediate visual trust.
Buy DigiCert Verified Mark Certificates from SSL2BUY to authenticate your brand identity across email platforms. Display your brand logo with verified trust in supported inboxes. -
Secure Email Content with Encryption (S/MIME or PGP)
To prevent messages from being read or altered by attackers during transit, you need to encrypt your emails. Specifically, when you are sending something sensitive like contracts, credentials, or even internal updates.
The two popular encryption standards are:
S/MIME
Secure Multipurpose Internet Email Extension is a popular standard that allows you to send encrypted emails that only the receiver can read. It also has a digital signature component that verifies the sender’s identity. Apps like Outlook, Apple Mail, and Thunderbird support it natively, so it’s easy to set up if you’re using those. You can secure business emails using S/MIME certificate that supports encryption and digital signing.
PGP
Pretty Good Privacy is an encryption used to protect emails and files. It uses public key cryptography to send encrypted emails to people without sharing private keys. It is an open-source way to boost email security and gives you full control over how your messages are encrypted and signed. It works well with tools like Thunderbird (via extensions like Enigmail) and a few browser-based options.
Whether you’re in a regulated industry or just value privacy, enabling encryption makes your communications stay private and protected from interception.
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Enable Multi-Factor Authentication for All Accounts
Setting up Multi-Factor Authentication (MFA) protects your email systems from phishing attacks.
Even if attackers get access to your credentials, the additional steps that MFA mandates like a code from your phone or a hardware key could save you from a potential cyber attack.
Here are some best practices when it comes to MFA.
- Enforce MFA for all accounts accessing email clients, webmail, and admin panels.
- Use App-based authenticators like Google Authenticator, Microsoft Authenticator, or Authy over SMS. These are more secure than text-based codes, which can be intercepted.
- Use hardware devices like YubiKey that offer stronger protection from phishing attacks.
- Integrate MFA with enterprise identity platforms like Okta, Azure AD, or Google Workspace and apply it across your email tools.
With MFA in place, you’re adding a simple but powerful layer of protection to your email environment.
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Train Users for Complete Email Client Security
Even with the best security tools, human error remains the biggest risk. That’s why regular user training is essential.
One of the most effective ways to build awareness is by running phishing simulations and email security workshops. These let your team practice spotting fake emails without the real-world consequences.
Train users to inspect sender domains (not just display names), hover over links before clicking, and think twice before opening unexpected attachments. These small habits can stop big problems.
Also, build a reporting-first culture. If something looks suspicious, it should be easy and safe to report it, ideally with a one-click button in the email client or via your IT helpdesk.
The best protection combines smart tools and smart people. Use security software to flag suspicious messages, but back it up with training that helps users trust their instincts and act.
In Summary
Email remains a top target for cyberattacks but with the right practices, you can dramatically reduce your risk. Start by choosing secure, updated email clients. Set up domain-level authentication (SPF, DKIM, DMARC). Encrypt sensitive content, enforce MFA, and train your team to stay vigilant. Together, these steps block threats, improve email deliverability, build sender trust, and keep your business communications secure in 2025 and beyond.
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