Top 11 email security best practices for businesses [2025]

"Is this email legitimate?" It's a question your team probably asks themselves several times a week, if not daily. And for good reason. Email-based attacks have become so sophisticated that even security professionals sometimes struggle to identify them at first glance.

The days when email threats were limited to obvious spam or easily spotted scams are long gone. Today's attackers research their targets, craft personalized messages, and leverage social engineering to bypass both technical safeguards and human judgment. They exploit our natural tendencies to be helpful, respond to authority, and act quickly under pressure.

This evolution in attack sophistication coincides with our increasing dependence on email for critical business functions. Against this backdrop, developing a robust email security strategy isn't just an IT consideration but a business imperative. 

The good news is that effective protection doesn't require enterprise-level resources. By understanding the threat landscape and implementing some practical, layered email security best practices, you can significantly reduce your organization's vulnerability.

What is email security, and why does it matter?

When we talk about email security, we're referring to the measures that protect your business communications from unauthorized access, compromise, or disclosure. It's about ensuring that the email messages you send and receive are legitimate, private, and safe.

Think about what passes through your company's email systems every day. Client information. Financial data. Strategic plans. Employee personal details. Login credentials and password resets. That's a goldmine for attackers, and they're working overtime to get their hands on it.

According to research, over 90% of successful cyberattacks begin with an email. And with the average cost of a data breach being $4.88 million, a significant breach can be existentially threatening.

But when your email security is effective, messages flow smoothly, legitimate communications get through, and threats are quietly neutralized before they can cause harm. 

Top 5 common security threats for businesses

Before diving into solutions, let's understand what we're up against. These are the most common and dangerous email-based threats targeting businesses today:

1. Phishing attacks

These are deceptive emails designed to trick recipients into revealing sensitive information or clicking on malicious links. They often impersonate trusted entities, like your bank, a coworker, or even your CEO. Modern phishing attempts, especially targeted spear phishing, are sophisticated and increasingly difficult to spot at first glance. They're designed to bypass security technology by exploiting human psychology.

2. Malware and ransomware

Email remains one of the primary delivery mechanisms for malicious software. A seemingly innocent attachment can harbor code that, once executed, compromises your systems. Ransomware is particularly devastating. Once activated, it encrypts your files and demands payment for their release. Modern ransomware attacks often include a double-extortion strategy: threatening to publish stolen data unless additional ransoms are paid.

3. Business email compromise (BEC)

This involves cybercriminals gaining access to legitimate business email accounts, often through phishing or password spraying. Once inside, they monitor communications to understand business processes and relationships before making their move. The typical BEC attack involves spoofing or impersonating an executive or vendor to redirect payments, request sensitive information, or gain access to additional systems. What makes these attacks particularly dangerous is that they come from authentic accounts within your organization or from trusted partners.

4. Insider threats

Not all email security threats come from external actors. Sometimes the danger comes from within your organization. Whether malicious or accidental, employee actions can lead to serious business email security incidents. This might include sharing credentials, exfiltrating sensitive information to personal email accounts, or falling for social engineering attacks. Departing employees with continued access to email systems represent a particular risk.

5. Account takeover

When credentials are compromised through phishing or other means, attackers can gain full control of email accounts. From there, they can access sensitive information, send emails as the legitimate user, and potentially move laterally through your organization. Account takeover attacks often begin with methods like credential stuffing, where attackers try common passwords or credentials leaked in other breaches across multiple accounts.

11 email security best practices for businesses

Now for the practical part, here are the most effective ways to secure your business emails:

1. Enable multi-factor authentication (MFA)

If there's one single step you take after reading this article, make it this one. MFA requires users to provide two or more verification factors to gain account access, making it significantly harder for attackers to break in even if they have a password. According to Microsoft, enabling MFA can block over 99.9% of account compromise attacks. That's an extraordinary return on a relatively simple cybersecurity investment. Implement MFA across all email accounts in your organization, with no exceptions.

2. Use secure email gateways

A secure email gateway sits between your email systems and the outside world, scanning incoming and outgoing email messages for threats before they reach your users. These tools can identify and block phishing attempts, malware, spam, and other email-based threats. Look for solutions that offer multiple detection engines, sandboxing capabilities for suspicious email attachments, and URL rewriting to protect against malicious links.

3. Train employees on phishing and scams

Your team is both your greatest vulnerability and your strongest defense. Regular security awareness training helps employees identify suspicious emails and understand the consequences of security breaches. Make training engaging and relevant with real-world examples and simulated phishing exercises. Focus on practical tips like hovering over links before clicking, verifying sender addresses, and being wary of unexpected email attachments.

4. Regularly update and patch systems

Outdated email clients and servers often contain security vulnerabilities that attackers can exploit. Establish a regular patching schedule to ensure all systems are protected against known threats. This includes not just your email server software, but also the operating systems, browsers, and applications that interact with your email systems. 

5. Implement strong password policies

Despite the rise of other authentication methods, passwords remain a critical first line of defense for email security. Enforce policies requiring complex passwords that are regularly changed and not reused across multiple services. Consider implementing a password manager for your organization to help employees maintain strong, unique passwords without resorting to sticky notes or text files.

6. Use email encryption

Email encryption protects the content of messages from unauthorized access, ensuring that only intended recipients can read sensitive information. Depending on your needs, you can implement encryption at different levels:

• Transport layer security (TLS) for encrypting the connection between email servers
• End-to-end encryption for protecting the actual content of messages
• Email signing certificates to verify sender identity and message integrity

7. Restrict email access on public Wi-Fi

Public networks are hunting grounds for attackers looking to intercept communications. When employees check email on public Wi-Fi at coffee shops, airports, or hotels, they expose themselves to risks like man-in-the-middle attacks that can capture login credentials or email content. Implement policies and technical controls to prevent employees from accessing business email on unsecured networks.

8. Automate offboarding to revoke email access immediately

When employees leave, their email access should be terminated promptly to prevent unauthorized access to company information. Manual processes are prone to delays and errors, creating security gaps. This requires implementing automated offboarding workflows that instantly revoke email access when an employee's status changes in your HR system. 

9. Enforce email access policies through device management

Not all devices are created equal when it comes to security. A company-managed laptop with full disk encryption and up-to-date software security provides a much stronger environment for email access than a personal smartphone with unknown applications and no passcode. Mobile device management (MDM) solutions let you create granular policies based on user roles, device types, and security compliance status. By controlling which devices can access your corporate email systems and enforcing security requirements, you create a more secure environment for sensitive communications.

10. Monitor and audit email activity

You can't protect what you don't monitor. Implement logging and monitoring of email systems to detect suspicious activity, such as unusual login locations, mass downloads of attachments, or irregular sending patterns that might indicate compromise. Regular audits can help identify security gaps before they're exploited and provide valuable forensic information if a breach occurs. 

11. Develop and test an incident response plan

Even with the best preventive measures, incidents can still occur. Having a well-documented data breach response plan helps minimize damage when something goes wrong.

Your plan should include steps for:

• Containing the breach
• Investigating the cause
• Recovering affected systems
• Notifying relevant parties
• Implementing preventive measures for the future

Email security tools and technologies

These practical tools can help implement the best practices we've covered:

Secure email gateways (SEGs)

SEGs scan all incoming and outgoing email traffic for malware, phishing attempts, and spam emails. They act as a first line of defense against email-based threats and typically offer features like content filtering, advanced spam filters, attachment scanning, and URL analysis.

Email encryption services

These tools ensure that sensitive information transmitted via email remains confidential and tamper-proof. Options range from built-in encryption features in email platforms to dedicated third-party solutions with advanced capabilities.

DMARC, SPF, and DKIM

This trio of authentication protocols helps verify that emails actually come from the domains they claim to be from, making it harder for attackers to impersonate legitimate senders:

• SPF (Sender Policy Framework): Specifies which servers are authorized to send email on behalf of your domain
• DKIM (DomainKeys Identified Mail): Adds a digital signature to emails, allowing recipients to verify they haven't been tampered with
• DMARC (Domain-based Message Authentication, Reporting, and Conformance): Tells receiving servers what to do with messages that fail SPF or DKIM checks

Endpoint protection platforms

Endpoint security solutions protect the devices that access your email, helping prevent malware infections and data theft. Modern endpoint protection goes beyond traditional antivirus to include behavior monitoring, application control, and automated response capabilities.

Zero-trust email security platforms

Based on the principle of "never trust, always verify," these platforms treat all emails as potentially malicious until proven otherwise. They typically combine multiple security technologies with continuous authentication and strict access controls.

How to build a company-wide email security policy

A comprehensive policy is the foundation of your email security strategy. Here's how to develop one that works:

Step 1. Define acceptable email use

Start by defining what constitutes acceptable use of your company's email systems. This should cover what types of information can be shared, guidelines around personal use of company email, and how employees should represent the company in external communications. Be specific without being overly restrictive. The goal is to protect your business while allowing your team to work effectively.

Step 2. Require regular employee training

Regular employee training needs to be a cornerstone of your policy. Security awareness isn't a one-time event but a continuous process that evolves with the threat landscape. Schedule training sessions that incorporate real examples of attacks targeting your industry, the latest threat trends, and practical exercises that help employees identify suspicious and phishing emails. The most effective training is relevant, engaging, and reinforced regularly through updates and reminders.

Step 3. Set guidelines for reporting suspicious email messages

Create a simple process that employees can easily follow when they encounter something questionable. Make sure everyone knows exactly who to contact, what information to include in their report, and what to do with the suspicious message itself. Most security experts recommend preserving suspicious emails until security teams can investigate, rather than deleting them immediately.

Step 4. Audit compliance quarterly

To ensure your security measures remain effective over time, implement quarterly compliance audits. These reviews should examine email system logs for unusual activities, verify that user permissions are appropriate, evaluate the effectiveness of your technical controls, and assess how well employees are adhering to established policies. Regular audits not only identify potential vulnerabilities but also demonstrate your organization's commitment to email security.

Step 5. Establish escalation protocols for suspected breaches

Define clear steps for responding to potential incidents, including initial assessment criteria, specific roles and responsibilities during an incident, appropriate communication channels, and thresholds for involving external experts or law enforcement. Having these protocols in place before an incident occurs significantly improves your ability to respond effectively.

Step 6. Include offboarding procedures in security controls

Finally, don't overlook the security implications of employee departures. Your policy should include specific offboarding procedures that address immediate revocation of email access, preservation of business-critical communications, transfer of important information to appropriate team members, and review of recent email activity for any suspicious behavior. These steps help ensure that employee transitions don't create security vulnerabilities for your organization.

How Rippling helps secure your company's communications

Managing email security becomes significantly easier with the right tools. Rippling's unified platform helps protect your business communications through these integrated HR, IT, and security functions:

• Automated employee lifecycle management: When employees join or leave your organization, Rippling automatically provisions or revokes their email access and associated permissions. The platform's workflow automation capabilities let you create custom security protocols for different departments, roles, or employment types, ensuring appropriate access levels throughout the employee lifecycle.

• Comprehensive device management: Rippling's MDM software capabilities enable you to enforce email security requirements across all company devices. This includes encryption, password policies, and access controls that prevent unauthorized email access from compromised or unsecured devices.

• Identity and access controls: Rippling's identity and access management software streamlines the implementation of cybersecurity best practices like multi-factor authentication, single sign-on, and role-based access controls. By centralizing user identity across all business systems (not just email), Rippling helps prevent password attacks and reduces the risk of unauthorized access.
• Security monitoring and alerts: Automated alerts notify security teams of potential threats, enabling rapid response before significant damage occurs. The platform's reporting capabilities provide insights into security posture and compliance status, helping you continuously improve your email protection strategy.

Email security best practices FAQs

What is the best way to secure email?

The most effective approach combines multiple layers of protection: technical controls like encryption and secure gateways, administrative measures like strong policies and regular audits, and human factors like security awareness training. No single solution can provide complete protection, but implementing the best practices outlined in this article will significantly reduce your risk.

How often should I review my company's email security policy?

At a minimum, conduct a full review annually. However, you should also update your policy whenever there are significant changes to your business operations, IT infrastructure, or the threat landscape. Many organizations find that quarterly reviews help keep their security measures aligned with current risks.

Why are strong passwords critical for email accounts?

Email accounts often serve as recovery options for other services and contain sensitive information about your business and communications. A compromised email account can lead to further account takeovers, data breaches, and business email compromise attacks. Strong, unique passwords provide a fundamental layer of protection that, when combined with multi-factor authentication, significantly reduces the risk of unauthorized access.

How can I recognize a phishing email?

Look for these common warning signs:

• Urgent requests for sensitive information or immediate action
• Slight misspellings in email addresses or domain names
• Generic greetings instead of your name
• Poor grammar or unusual phrasing
• Suspicious attachments or links that don't match their descriptive text
• Requests to log in to accounts via email links instead of going directly to websites

Remember that sophisticated phishing attempts may avoid these obvious red flags. When in doubt, verify requests through another communication channel before taking action.

This blog is based on information available to Rippling as of May 20, 2025.

Disclaimer: Rippling and its affiliates do not provide tax, accounting, or legal advice. This material has been prepared for informational purposes only, and is not intended to provide or be relied on for tax, accounting, or legal advice. You should consult your own tax, accounting, and legal advisors before engaging in any related activities or transactions.