9 Email Security Best Practices (Ultimate Guide 2025)

3.4 billion emails are sent by cyber criminals every day...

And according to the FBI's Internet Crime Complaint Center, email-based attacks have surged by over 300% since 2020.

As new threats continue to emerge, you'll need to make sure your organization's email security practices are maturing to keep up with these threats.

This playbook will guide you through the essential email security best practices you need to know to educate employees, mitigate risks, and protect your organization against all types of email-based attacks.

Here are the 9 email security best practices you need to know at a glance:

1. Train employees to recognize phishing attacks
2. Invest in training that focuses on human risk
3. Use strong passwords (and store them safely)
4. Implement multi-factor authentication (MFA)
5. Protect against malicious email attachments
6. Use advanced email security tools
7. Regularly update software and systems
8. Foster a positive security culture
9. Establish clear reporting processes

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Types of email attacks to watch out for

According to a 2024 survey of 500 cybersecurity leaders:

• 94% of organizations experienced an email security incident
• 91% experienced data loss
• 94% fell victim to phishing

And the cyber threat landscape is always evolving...

Out of nearly 100 million phishing emails blocked by Gmail filters, 68% belonged to a previously unknown scam.

This means if you're on the frontline of defense, your best practices and training needs to be constantly evolving too.

Phishing attacks: 94% of organizations experienced phishing attacks in the past year, with 96% suffering negative impacts as a result.

Malware: Malicious emails containing malware attachments or links can infect your business's network and compromise data.

Credential harvesting: Credential harvesting is when malicious actors attempt to steal employees' login credentials through phishing emails or fake login pages. These credentials can then be used to gain unauthorized access to company systems, compromise sensitive data, or launch further attacks.

Social engineering attacks: Social engineering tactics exploit human psychology to manipulate employees into disclosing information or performing unauthorized actions.

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1. Train employees to recognize phishing attacks

Modern phishing attacks are cost-effective, scalable, and often successful because employees aren’t fully prepared to recognize them.

Training employees to recognize and report phishing attacks is essential for mitigating risks and strengthening your organization’s email security posture.

Teach employees to spot red flags

Attackers leverage human psychology, using fear, urgency, or curiosity to trick recipients into clicking on links or downloading files.

Phishing emails may include suspicious links, malicious attachments, or urgent requests.

Key indicators to teach employees include:

• Generic greetings instead of personalized salutations.
• Requests to verify login credentials or process unexpected transactions.
• Subtle inconsistencies in email domains or sender details.
• Note: Often, just hovering over a link to check the actual URL can prevent a phishing attempt from succeeding.

Address business email compromise (BEC)

Business Email Compromise attacks (BEC) are particularly dangerous as they target employees with highly personalized and believable messages.

While ransomware tends to grab headlines, BEC continues to be the most prolific and costly form of email attack. 

Deepfake AI technology heightens the danger of BEC attacks by making them more convincing and easier to execute.

BEC attacks have become increasingly sophisticated, often using spoofed email addresses or minor domain changes that are hard to detect.

To combat this threat, employees should be trained to, employees should be empowered to question unusual requests, no matter who they seem to come from.

Simulate realistic phishing scenarios

Simulations are a powerful way to prepare employees for real phishing attacks.

They let people practice spotting and reporting threats in a safe environment.

When employees experience a simulated attack, they’re much more likely to recognize and avoid real ones.

No matter how advanced the AI technology driving a BEC attack may be, the tactic will still set off certain psychological alarm bells in a trained employee.

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2. Invest in training that focuses on human risk

Reducing phishing risk offers one of the highest returns on investment when it comes to bolstering your organization’s email security posture.

But not all training is created equal.

Traditional security awareness training often feels like a compliance exercise for most employees - something people were forced to do, not something they're excited about.

To achieve real, measurable behavior change, training programs must go beyond compliance and focus on engaging employees effectively and measurably changing their behavior. 

Threat reporting is an excellent metric to gauge a program's success because this behavior translates directly to a reduction risk.

Personalize training to each employee

You can’t expect a one-size-fits-all model to resonate with everyone.

To be effective, it must address the unique security risk profiles and attacks that employees face based on their roles and responsibilities.

By tailoring the program to individual needs, employees feel the training is relevant, making them more likely to engage.

Make training genuinely engaging

Engagement is key to reducing human error and building a culture of vigilance.

Training should be interactive, enjoyable, and rewarding.

The gamification model puts users in the driver’s seat.

Employees feel they’re part of the program, not forced into it.

It becomes something they want to do, not something they have to do.

By using incentives like leaderboards and rewards, employees are motivated to improve, and reporting suspicious emails becomes second nature.

At Hoxhunt, for example, we use a carrot model that opens doors to better engagement.

This is why +60% of employees report cyber threats within a year of training.

Provide continuous and adaptive learning

Training must evolve with the threat landscape to remain effective.

Threat actors are constantly refining their tactics, from QR code phishing to deepfake attacks.

Training can’t be a one-off; it needs to be continuous and adaptive.

Measure and track results

You can’t improve what you don’t measure.

Effective training programs provide metrics that help organizations track performance and adjust strategies accordingly.

Before, AES only saw around 10% of employees regularly engaging with training, and a scant few were actually reporting phishing simulations.

After implementing a more engaging program, reporting rates jumped to 65-70% in under a year.

Metrics like reporting rates and employee engagement are essential for understanding the impact of your training (we broke down the most essential phishing metrics here).

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3. Use strong passwords (and store them safely)

Passwords are a critical component of your email security measures.

Weak passwords and reused credentials are easily exploited by malicious actors through methods like brute-force attacks, credential stuffing, and social engineering tactics.

A single compromised password can lead to unauthorized access and expose an entire corporate network.

Ensure employees' passwords are strong

Passwords are one of the most common entry points for malicious actors to access email systems.

Using strong passwords add an extra layer of security, making it significantly harder for attackers to break in.

Best practices for creating strong passwords:

• Use at least 13 characters or more, combining uppercase and lowercase letters, numbers, and symbols.
• Avoid simple passwords like “1234” or “password.”
• Don’t reuse passwords across accounts—this limits the risk of compromised accounts cascading to other systems.
• Update passwords regularly to protect against security vulnerabilities.

Make password managers mandatory

Managing complex passwords for multiple online accounts is challenging.

But that’s where a password manager comes in.

Why use a password manager?

• Safely stores advanced passwords for multiple systems, including email service providers and business communication tools.
• Generates strong passwords you can copy and paste securely.
• Provides an alternative to risky storage methods like sticky notes, browser autofill, or computer files.

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4. Implement multi-factor authentication (MFA)

Passwords alone are no longer enough to protect email accounts, and sensitive email messages.

Multi-factor authentication (MFA) adds an extra layer of security to the authentication process, requiring users to verify their identity with multiple authentication factors.

Research shows that MFA can prevent 99.9% of automated cyber attacks, making it a cornerstone of effective email security practices.

Why MFA is critical for email security

MFA enhances protection by combining strong passwords with an additional verification method such as:

• A one-time password (OTP) delivered via mobile phones or email clients.
• Biometric authentication like fingerprints or facial recognition for personal accounts and corporate systems.
• Hardware tokens or software-based authenticators for sensitive email services.

Adding MFA is like locking a vault with multiple keys.

Even if one is stolen, the bad actor can’t access the contents.

This layered approach reduces the risks of unauthorized access, and account compromise.

Follow these guidelines for implementing MFA

The choice of authentication factors should balance convenience with security without frustrating employees.

• Select the right factors: Use biometrics, hardware tokens, or app-based authenticators based on the sensitivity of the system or email services being protected.
• Enforce regular updates: Keep MFA systems updated with the latest security patches to address potential vulnerabilities.
• Enable account lockout policies: Block brute-force attacks by locking accounts after repeated failed login attempts.
• Monitor for anomalies: Identify signs of MFA fatigue attacks, where repeated prompts could indicate malicious intent. (Attackers rely on fatigue to bypass MFA so be sure to monitor these patterns to mitigate cyber risks).

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5. Protect against malicious email attachments

94% of malware is delivered through email attachments.

Which makes securing email attachments a critical part of any email security strategy.

Give employees these guidelines for email attachments

Avoid opening attachments from unknown sources: Never download or open files from an unknown sender or unsolicited emails.

Scan attachments with antivirus software: Use reliable antivirus programs to scan attachments for malicious code before opening them.

Use email security gateways: Deploy a secure email gateway to filter out emails containing harmful attachments. These solutions block malicious payloads before they reach the inbox.

Limit attachment types and enable file restrictions: Configure email servers to block potentially dangerous file types, such as .exe or .zip files, that are often used to deliver malware attacks.

Cloud-based file sharing: Reduce reliance on email attachments for sharing critical files by using cloud-based file sharing platforms with built-in security measures.

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6. Use advanced email security tools

Advanced email security tools are indispensable for mitigating common email security threats.

Solutions like email security gateways (ESGs), spam filters, and authentication protocols will give you an additional layer of protection against email security threats.

Look into email security gateways

Email security gateways (ESGs) defend against malicious activity by filtering out spam messages, malicious links, and attachments from emails before they reach users’ email inboxes.

Key benefits of ESGs include:

• Email filtering to block spam emails and suspicious email links.
• Scanning for malicious content in both the email body and file attachments.
• Protecting against spear phishing attacks and other social engineering attacks.
• Enforcing email security guidelines and improving compliance with security standards.

Use spam filters

Spam filters are essential for separating spam email from legitimate emails.

They help by:

• Reducing exposure to phishing schemes and malicious links.
• Blocking emails from unknown senders attempting to exploit email security weaknesses.
• Limiting the risk of email spoofing, where attackers impersonate trusted email addresses.

Ensuring email authentication with DMARC, DKIM, and SPF

Authentication protocols like DMARC, DKIM, and Sender Policy Framework (SPF) provide critical defenses against email spoofing and unauthorized use of domain owners’ email addresses.

• DMARC verifies the authenticity of incoming emails and ensures that messages claiming to come from a trusted domain are valid.
• DKIM uses encryption to add a unique signature to emails, verifying that their email contents have not been altered.
• SPF helps mail servers confirm that incoming messages are from authorized sources, preventing abuse by spammers and attackers.

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7. Regularly update software and systems

One of the simplest yet most effective email security practices for employees is ensuring that all software and systems are regularly updated.

Outdated software often contains vulnerabilities that cybercriminals exploit to deploy malicious software, compromise email inboxes, or infiltrate company emails.

How to ensuree employees keep systems up to date

Enable automatic updates: Employees should enable automatic updates on all devices, including email clients and operating systems.

Beware of public wi-fi networks: Warn employees about accessing email accounts or downloading updates over public Wi-Fi networks to prevent interference or exposure to malicious activity.

Employee training and awareness: Ensure software updates are covered in your security awareness training, employees should understand how delaying updates can make their devices vulnerable to email security threats.

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8. Foster a positive security culture

Building a strong security culture within your organization is one of the most impactful ways to combat email security threats.

Employees are your first and last line of defense against phishing attacks.

A positive security culture empowers employees to recognize and respond effectively to email security threats and turns cybersecurity into a shared responsibility - not something that just happens in the background.

Steps to build a positive security culture

Lead by Example: Business leaders and managers should model email safety practices, such as using two-factor authentication and adhering to corporate email policies. Visible commitment to security encourages employees to follow suit.

Encourage open communication: Create a safe environment where employees feel comfortable reporting email security risks or suspicious activities.

Reward good security behavior: Recognize and reward employees who consistently follow email security guidelines or report malicious content. Positive reinforcement helps build habits.

Integrate security into daily activities: Make security a routine part of employees’ work by integrating training into their daily workflow.

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9. Establish clear reporting processes

An effective email security strategy isn't just about identifying threats; it’s about having a clear plan of action when those threats are detected.

By establishing clear reporting processes, you can ensure that these threats are handled swiftly and effectively.

Design an intuitive reporting system

Creating a streamlined incident reporting system is crucial for maintaining email security across your organization.

Your reporting process should include specific guidelines for employees to flag potential phishing attempts, malicious attachments, or unusual sender behavior.

This means setting up a dedicated email address or ticketing system where employees can forward suspicious messages, along with clear instructions on what information to include in their reports.

Encourage active participation

Train your team to document key details such as the sender's email address, subject line, timestamp, and any unusual elements that triggered their suspicion.

This approach helps your security team quickly assess and respond to potential threats while building a database of attack patterns specific to your organization.

Consider implementing a simple classification system that helps employees categorize the urgency of their reports.

For instance, emails containing urgent payment requests or executive impersonation attempts should be flagged as high-priority incidents requiring immediate attention.

Remember that positive reinforcement plays a vital role in maintaining strong reporting habits.

Acknowledge employees who consistently report suspicious emails.

This creates a culture where vigilance is valued and security-conscious behavior becomes second nature.

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Common email security compliance frameworks

NIST Cybersecurity Framework

The National Institute of Standards and Technology (NIST) provides comprehensive guidelines for email security that have become the gold standard for organizations worldwide.

Their framework emphasizes:

• Identification and authentication of email senders
• Implementation of encryption for sensitive communications
• Regular security awareness training for employees
• Incident response planning and documentation

NIST's guidelines specifically recommend implementing DMARC, SPF, and DKIM protocols to verify email authenticity and prevent domain spoofing – critical steps for maintaining a secure email environment.

ISO 27001

This international standard provides a systematic approach to email security as part of overall information security management:

• Requires documented email security policies
• Mandates regular risk assessments
• Establishes controls for handling sensitive information in emails
• Sets standards for email backup and archiving

GDPR Email Requirements

For organizations handling EU residents' data, GDPR compliance in email security is non-negotiable:

• Mandates encryption of personal data in transit
• Requires explicit consent for email marketing
• Establishes strict data breach notification protocols
• Sets standards for email data retention and deletion

SOC 2 Email Security Controls

SOC 2 certification demonstrates your commitment to email security through:

• Regular monitoring of email systems for suspicious activity
• Implementation of access controls and authentication measures
• Documentation of email security procedures
• Continuous employee security awareness training

Practical implementation

To effectively implement these security frameworks:

1. Start with a comprehensive email security assessment
2. Develop policies aligned with relevant compliance requirements
3. Deploy technical controls recommended by chosen frameworks
4. Establish monitoring and reporting mechanisms
5. Conduct regular audits and updates

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Automate security training and drive lasting behavior change with Hoxhunt

Transform employee behavior with adaptive phishing simulations and AI-powered security training creation while meeting compliance needs with ease.

Hoxhunt offers phishing training, automated security awareness training and advanced behavior change - all in one human risk management platform.

Measurably change behavior by providing personalized, interactive and bite-sized training that people genuinely enjoy.

How do we know our process works?

• 20x lower failure rates
• 90%+ engagement rates
• 75%+ detect rates

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_Sources

^{Egress Email Security Risk Report 2024 – Egress, 2024
Astra Security - Phishing Attack Statistics 2025 – Astra Security, 2025
Information Security Buzz - Email Security Risk Remains High – Information Security Buzz, 2024
Kaspersky - Phishing Scams & Attacks – Kaspersky, 2024
Sprinto - Phishing Attack Statistics – Sprinto, 2024
Varonis - Cybersecurity Statistics and Trends – Varonis, 2024
Microsoft - Multi-Factor Authentication – Microsoft, 2024
Verizon - Data Breach Investigations Report – Verizon, 2024
Egress Email Security Risk Report 2024 – Egress, 2024
Kaspersky - Phishing Scams & Attacks – Kaspersky, 2024}