Email security is a critical aspect of protecting sensitive information and maintaining trust in today’s fast-paced digital environment.
While inbound threats like phishing, malware, and spam often grab the spotlight, outbound email security is just as important.
A single misdirected email or unintentional data leak can lead to significant financial, legal, and reputational consequences.
In this guide, we’ll explore 15 essential email security best practices—including actionable tips specifically designed for employees—to help your organization maintain secure and efficient email communication.
We will also show you how you can use a SaaS addin for MS Outlook to prevent your employees from sending emails to the wrong recipients, including client mix-ups and accidental auto-completes.
So, whether you’re a business owner, IT professional, or everyday user, these email security best practices will help you stay proactive and secure.
15 Email Security Best Practices for Employees: What Every Team Member Should Know
- Review and Double-Check Recipients
- Use Data Loss Prevention Loss Tools
- Correct Use of To, Cc, and Bcc Fields
- Enable Email Delay Rules
- Use Encrypted Email for Sensitive Information
- Use Strong Passwords
- Use Two-factor Authentication
- Use Standardized Email Templates
- Keep an Eye Out for Suspicious Emails
- Inspect Links Before You Click on Them
- Avoid Posting Your Email on Public Sites or Forums
- Review Your Email Security and Privacy Settings
- Use Corporate Email Only on Approved Devices
- Use Email Security Standards
- Educate Your Employees on the Best Email Security Practices
- Review and Double-Check Recipients
One of the simplest yet most effective email security best practices is to always review and double-check recipients before sending an email.
The UK Information Commissioner’s Office (ICO) reports that the most common data security incident is emailing data to the wrong recipient.
Sending emails to the wrong recipient is a common mistake that can happen for several reasons. Here are some of the most frequent causes:
- Auto-complete Errors: Email clients often auto-complete email addresses based on previous contacts. If you’re not careful, you might select the wrong address from the suggested list of emails.
- Similar Email Addresses: If you have multiple contacts with similar names or email addresses, it’s easy to mix them up.
- Copy-Pasting Errors: Copying and pasting email addresses can lead to mistakes, especially if you’re in a hurry.
- Mis-clicks: Clicking on the wrong contact in your address book or email client can happen, especially if you’re multitasking.
- Email Aliases: Using email aliases or distribution lists without verifying the members can lead to sending emails to unintended recipients.
- Drafts and Templates: Reusing drafts or templates without updating the recipient information can cause errors.
Sending an email to the wrong person can lead to various consequences, including privacy breaches, professional and reputational damage, security risks, legal issues, and personal embarrassment.
Such mistakes can erode trust and cause misunderstandings in both personal and professional settings.
To avoid these issues, it’s crucial to double-check the recipient field, use distinct names for contacts, and consider email verification tools.
Consider using email security solutions like SendGuard for Microsoft 365
SendGuard for Microsoft 365 is an MS Outlook add-in that prompts users to verify recipients and attachments before sending emails, helping to minimize the risk of sending emails to the wrong people.
This confirmation step ensures that the sender reviews and verifies the content of the email, reducing the risk of accidental disclosure of sensitive information to unintended recipients.
SendGuard displays the following confirmation prompt to prevent misaddressed emails.
- Use Data Loss Prevention Loss tools
Organizations manage various types of sensitive information, including:
- Financial data
- Proprietary data
- Credit card numbers
- Protected Health Information e.g. health records
- Social security numbers
To safeguard sensitive data and minimize the risk of oversharing, organizations require a method to prevent users from inappropriately sharing sensitive information with unauthorized individuals. This approach is known as data loss prevention (DLP).
As email has become the primary mode of business communication, implementing Data Loss Prevention (DLP) for email is now regarded as a crucial security measure.
Email DLP tools can use rule-based systems to look for specific keywords, patterns, or data types (like credit card numbers), and more advanced machine learning algorithms that understand the context of communications.
Once sensitive data is detected, the DLP system can flag the email, prevent the email from being sent or quarantine the email until it can be reviewed and approved.
As demonstrated earlier, human error is the primary cause of data breaches. Implementing a human-led Data Loss Prevention (DLP) strategy can significantly reduce the risk of data loss.
SendGuard has a built-in DLP module which scan email content and attachments for sensitive information such as personally identifiable information (PII), protected health information (PHI) and intellectual property (IP).
It prompts users to verify their recipient list and ensure attachments are safe to send. Emails can be blocked if sending confidential information via email violates your corporate policy.
By using SendGuard, you are empowering your users to make data protection decisions. Machine learning is not always the right way to prevent misdirected emails, especially when it comes to determining if you are sending the email to the right person with the correct attachments.
- Correct use of To, Cc and Bcc fields
Understanding the correct use of To, Cc, and Bcc fields is a vital part of email security best practices for employees.
“To” is for primary recipients who need to take action, while “Cc” keeps others informed without requiring their response. “Bcc” protects privacy by hiding email addresses, preventing reply-all chains, and maintaining confidentiality.
How SendGuard helps:
In the confirm recipients and attachments prompt (see Figure 1) you can change the recipients in the To, Cc and Bcc field if you change your mind.
SendGuard can warn and recommend BCC if email has too many recipients in the “To/Cc” field to mitigate unintentional unauthorised email address exposure. Ensure that emails with large recipient lists are sent securely preventing unintended visibility of email addresses.
- Enable Email Delay Rules
Delaying emails can be a helpful strategy to prevent sending them to the wrong person. By setting a delay, you give yourself a buffer period to review the email one last time before it actually gets sent.
This extra time allows you to double-check the recipient list, ensure the content is appropriate, and confirm that any attachments are correct.
If you notice any mistakes or decide to make changes, you can cancel or edit the email before it goes out, reducing the risk of errors and improving the overall quality of your communication.
How SendGuard helps:
SendGuard allows you to delay emails (internal and/or external) to allow a reliable recall of emails before they are sent.
You also have the option to bypass this delay email rule for urgent emails.
- Use Encrypted Email for Sensitive Information
Emails are frequently used to share sensitive information, including financial data, legal contracts, confidential product details, sales reports and forecasts, patient health records, and customer or employee information.
Consequently, mailboxes can accumulate significant amounts of sensitive data, making information leakage a serious risk for your organization.
Email encryption is a security measure that encodes the contents of an email to prevent unauthorized access. This ensures that only the intended recipient can read the message, protecting sensitive information from cybercriminals.
Email encryption secures the contents of an email by converting it into unreadable ciphertext, which can only be decrypted by the intended recipient using a private key.
This process typically involves a pair of keys: a public key for encryption and a private key for decryption.
Microsoft offers encryption through its Microsoft Purview Message Encryption to encrypt email messages and various attachments.
- Use Strong Passwords
Using strong passwords is one of the foundational email security best practices to protect accounts from unauthorized access and potential breaches.
Strong passwords are more resistant to brute-force attacks, where attackers try numerous combinations to guess your password.
For accounts containing sensitive information, such as financial or medical records, a strong password is essential to keep this data secure.
Weak passwords can be easily guessed or cracked, leading to data breaches and identity theft.
Strong passwords typically include a mix of uppercase and lowercase letters, numbers, and special characters. Some examples are:
- CorrectH0Rseb@tterySt4ple
- L4%6:32WKcZpi{eb#4t
- Tr0ub4dor&34
NIST Standards for Creating Strong Passwords
The National Institute of Standards and Technology (NIST) provides guidelines for creating strong passwords:
Length: Passwords should be at least 8 characters long, with a recommended minimum length of 15 characters.
Complexity: Use a mix of uppercase and lowercase letters, numbers, and special characters.
Avoid Common Patterns: Do not use easily guessable information like common words, phrases, or patterns.
Allow All Characters: Accept all printable ASCII characters and spaces in passwords.
Blocklist: Check passwords against a blocklist of commonly used or compromised passwords.
- Use Two-factor Authentication
Two-factor authentication (2FA) is a security process that requires two different forms of identification to verify a user’s identity before granting access to an account or system. This adds an extra layer of security beyond just a password.
Some Common 2FA Methods
- SMS Verification: A code is sent to your phone via text message.
- Authenticator Apps: Apps like Google Authenticator or Microsoft Authenticator generate time-based codes.
- Hardware Tokens: Physical devices that generate codes.
- Biometrics: Fingerprint or facial recognition
- Use Standardized Email Templates
Using email templates in your security strategy, can enhance the overall security of your email communications and protect sensitive information more effectively.
One of the main benefits of using email templates is that it helps reduce the likelihood of human error, which is a common cause of security incidents.
Templates can be designed to comply with organizational policies and regulatory requirements, ensuring that all communications meet necessary security standards.
Tips for Creating Secure Email Templates
Standardize Content: Ensure that all templates include standardized content that has been reviewed for security. This includes avoiding sensitive information and ensuring that all links and attachments are safe.
Include Security Disclaimers: Add disclaimers at the bottom of your emails to remind recipients about the importance of email security. Moreover, this will help verify the sender’s identity before clicking on links or opening attachments.
Use Clear and Concise Language: Clear and concise language helps prevent misunderstandings and reduces the risk of phishing attacks.
Incorporate Branding: Use consistent branding elements such as logos and color schemes. This helps recipients recognize legitimate emails from your organization and spot phishing attempts more easily.
Regularly Update Templates: Periodically review and update your templates to ensure they comply with the latest security policies and best practices.
- Keep an eye out for suspicious emails
Cybercriminals tend to use clever methods to trick users into opening email accounts that contain confidential information. Here are a couple of steps to recognize suspicious emails:
Emails asking for Payment
Be cautious with emails asking for payments or containing attachments like receipts, invoices, or purchase orders. These could be sneaky links to malware sites.
Before you click on any link or open an attachment, hover your cursor over the link to check if it’s legit.
If the URL looks like it’s from a reputable site, it’s best to type it manually into a new address bar to verify it.
Email that has grammatical or spelling error
Credible sources will have proper and or personalized emails without any grammatical or spelling error.
Emails asking you to take urgent action
Be aware of threatening messages, particularly emails that state your account has been suspended or deactivated. Other threatening type of emails may prompt you to click on an unverified link that may take you malware sites.
- Inspect links before you click on them
Email hyperlinks can sometimes lead to a different web domain than they appear to.
Attackers create domains that closely resemble legitimate ones, such as replacing an “o” with a “0” (e.g., “go0gle.com” instead of “google.com”).
Display name can be falsified in an email to make it appear as if it’s from a trusted source, while the actual email address is different.
If you receive an unexpected email with a link, especially one asking for sensitive information, be cautious and verify its legitimacy before taking any action.
Before clicking, hover your cursor over the link to see the actual URL. This can reveal if the link is pointing to a suspicious or unexpected site.
Look closely at the URL for any misspellings or unusual characters that might indicate a spoofed domain.
- Avoid posting your email on public sites or forums
Avoid posting your email on public sites or forums—this is a crucial part of email security best practices for employees.
Most often, scammers monitor public forums for email addresses. This is how users receive scam via email. Do not post your corporate email address on any public site or forum.
Cybercriminals can use publicly available email addresses to send targeted phishing emails, attempting to trick employees into revealing sensitive information or clicking on malicious links.
- Review your email security and privacy settings
Reviewing your email security and privacy settings will help you ensure your account remains secure. Here are some steps you can consider:
- Enable two-factor authentication for added layer of security by requiring a second form of verification, such as a code sent to your phone.
- Check which apps and services have access to your email account and remove any that you no longer use or trust.
- Review how your data is used and shared. Make sure your email provider is not sharing your information with third parties without your consent.
- Enable notifications for any suspicious activity or login attempts.
- Use corporate email only on approved devices
Business emails often have stricter security protocols. Mixing personal use can expose sensitive business information to potential security breaches.
Employers typically have the right to monitor business email accounts. Using your business email for personal matters can compromise your privacy as well.
- Use Email Security Standards
Three key email security standards for filtering spam messages are SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance).
DMARC, DKIM, and SPF are three email authentication methods that work together to prevent spammers, phishers, and other unauthorized parties from sending emails on behalf of a domain they do not own.
Without these authentication methods, spammers and phishers can easily impersonate your domain, sending fraudulent emails that appear to come from your legitimate address.
DMARC, DKIM, and SPF need to be configured in the domain’s DNS settings. Administrators can reach out to their DNS provider for assistance, or use tools provided by their web hosting platform to upload and edit DNS records.
- Educate Your Employees on the Best Email Security Practices
Many industries have regulations regarding data protection. Training helps ensure that employees follow these regulations, avoiding potential fines and legal issues.
Key topics to cover include phishing awareness, password management, two-factor authentication, recognizing and handling suspicious emails, data protection, email encryption, company policies, incident response, social engineering tactics, safe use of email on mobile devices, and the importance of regular updates.
Complement Outbound Email Security with SendGuard
While email security practices are essential, a dedicated email security solution can significantly enhance overall email safety. SendGuard for Microsoft Outlook prompts employees to confirm the recipient’s address, ensures the correct documents are attached, and verifies that any sensitive information is appropriate for the recipient.
Regulations such as GDPR, HIPAA, CCPA, and SOX mandate measures to prevent the accidental, unauthorized disclosure of sensitive data, including medical records and financial transactions.
SendGuard encourages a behavioral shift by prompting employees to carefully review the emails they send, whether internally or externally.
The SendGuard addin for Outlook is Microsoft 365 certified and is thoroughly evaluated against security controls based on industry standards, including SOC 2, PCI DSS, and ISO 27001.
Learn More about SendGuard for Microsoft Outlook 365.
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