10 Email Security Best Practices Every Small and Medium Business Should Follow in 2025

As mentioned in the previous articles, in 2025, email remains the number one entry point for cyberattacks on small and medium businesses. Attackers now use AI-powered phishing and even deepfake voice/emails to trick victims – for example, recently hackers mimicked a defense minister’s voice in an email scam. One study found that traditional email filters still let through an average of 67.5 phishing emails per 100 users per month. These trends mean every SMB must take email security seriously. Below are 10 clear, practical email security best practices (mixing tech controls and simple policies) to keep your business safe in 2025.

1. Enable Multi-Factor Authentication (MFA)

Requiring Multi-Factor Authentication (MFA) is one of the most effective steps in email security. Instead of just a password, MFA asks for a second factor (like a text code or mobile app prompt) when logging in. This means even if a hacker steals a password, they can’t get into the account alone. In fact, Microsoft reports MFA can block over 99.9% of automated attacks on accounts. Since 80% of breaches involve stolen or weak credentials, MFA dramatically cuts your risk.

Why it matters: Passwords are often weak or reused. One study found that 81% of data breaches involve weak passwords. MFA adds a “second lock” so a bad guy can’t get in even if they phish your password. This extra step thwarts most automated hacks and phishing attacks.

How to do it: Turn on two-factor login for every email and business account.

• For Microsoft/Google email: Go to Account Settings > Security and enable 2FA (usually by SMS code or authenticator app).

• For business apps: Encourage use of authenticator apps (like Google Authenticator or Microsoft Authenticator) instead of SMS, for more security.

• Communicate this to staff: Explain that after their password, they’ll be prompted for a code or app approval. It only takes a minute to set up and is usually a one-time configuration per device.

Using MFA is easy and often free. It’s now standard on email and cloud services – just turn it on to lock out most attackers automatically.

2. Set Up SPF, DKIM, and DMARC to Protect Your Domain

Implementing SPF, DKIM, and DMARC helps prevent spammers from impersonating your business email domain. In simple terms, these are email authentication records in your domain’s DNS that tell other mail servers, “Yes, emails from us are genuine”. For example, SPF lists the servers allowed to send your mail, DKIM adds a cryptographic signature, and DMARC tells receivers what to do with any unauthenticated mail. Together, they make sure others can verify your messages.

Why it matters:  Without these records, spammers can spoof your address (like “boss@yourcompany.com”) and fool customers or employees into sending data or money. Cloudflare warns that if SPF/DKIM/DMARC aren’t set up correctly, your real emails might get quarantined as spam or not delivered at all, and attackers could impersonate your brand. In short, unauthenticated domains are ripe targets for phishing and email fraud.

How to do it: Most domain hosts and email services (Google Workspace, Microsoft 365, etc.) provide simple instructions to add these DNS records. Steps include:

• SPF: Log into your domain or DNS manager and create a TXT record like v=spf1 include:_spf.google.com ~all (exact value depends on your email host). This lets others know which servers send email for you.

• DKIM: Enable DKIM signing in your email provider’s settings. It will give you a TXT record to add to DNS. This adds a digital signature so receivers can verify emails haven’t been altered.

• DMARC: Finally, add a DMARC TXT record, e.g., v=DMARC1; p=quarantine; rua=mailto:you@yourdomain.com. This tells other servers to reject or quarantine mail that fails SPF/DKIM. You can start with p=none (monitor mode) and check reports, then move to a stricter policy.

If this sounds technical, ask your IT person or email provider for help; they often have wizards or support guides. Setting up SPF/DKIM/DMARC only takes a few minutes in most control panels, but it greatly improves your SMB email protection. As Cloudflare explains, these methods “help prevent spammers, phishers, and other unauthorized parties from sending emails on behalf of [your] domain” - cloudflare.com.

3. Train Employees on Phishing and Secure Email Use

Employees are your first line of defense: teach them to recognize scams. Security awareness training is crucial. For example, many phishing attacks now create urgent, official-looking emails demanding action (think “Your invoice is overdue – pay now!” or “CEO needs immediate wire transfer”). If staff know how to spot these red flags, your risk drops dramatically.

Why it matters: Human error causes most breaches. The latest Verizon Data Breach Investigations Report finds 68% of cyberattacks involve some form of human error. Attackers prey on unwary users with emails full of typos, spoofed logos, or strange links. A well-trained team can spot and report suspicious emails before damage is done.

How to do it:

• Regular training: Do a short security briefing at least once a year (or quarterly emails/tips). Cover common scams: phishing emails, fake invoices, package delivery scams, etc.

• Phishing simulations: Use a safe “test email” service to send fake phishing emails to employees. Those who click should get a quick lesson on what to look for (unusual sender address, urgent requests, generic greetings).

• Clear protocols: Tell staff to never reply to or click links in unexpected requests for money or sensitive data without verifying. For example, if a “boss” asks for a wire transfer, call them on a known number first to confirm. Establish a simple incident-report process (e.g., forward suspect emails to your IT or security address).

• Resources: Provide cheat sheets or posters on phishing signs. Encourage skepticism: hovering over links to see where they lead, checking sender email addresses carefully, and looking out for typos or mismatched domains.

• Technical expertise: Having an employee with dedicated experience in email security can be an easy relief for your company. In this way, there would not be a need to invest so much in training because every suspicious message can simply be discussed with the expert.

Effective training pays off. Companies that invest in awareness see far fewer clicks on real phishing emails. Security programs like these turn employees into a protective shield, not a liability. As one source notes, well-trained employees dramatically reduce a company’s attack surface from phishing and social engineering.

4. Use a Secure Email Gateway or Filtering Service

SMBs should use strong filtering and anti-malware for email. Whether your email is on Office 365, Gmail, or another platform, turn on advanced spam/virus scanning. These tools check attachments and links for threats before they reach inboxes.

Why it matters: Basic spam filters miss some threats. In one study, even leading secure email gateways allowed dozens of phishing emails through each month. Attackers also send malicious attachments (like infected PDFs or macros) that can install malware. By using an anti-phishing email service or gateway, you add another layer of defense, catching threats that slip past users and default filters.

How to do it:

• Enable built-in filters: Make sure your email system’s spam and malware filtering is active (for example, Microsoft 365 Defender or Google Workspace security settings). Always keep the filtering definitions up to date.

• Third-party add-ons: Consider services like Proofpoint, Mimecast, or free solutions that integrate with your email to quarantine suspicious emails. For instance, some small business email hosts include robust filtering for a small fee.

• Attachment screening: Block or scan attachments like .exe or macros by default, and allow only necessary file types.

• Link protection: Some gateways rewrite or check links in emails to prevent clicking on known malicious sites. Use this if available.

In short, even with good SPF/DMARC and training, you still need technical filters. Given the rise of AI phishing, these tools are evolving, but they catch a high percentage of attacks automatically. Think of it like a guard at your email “gate,” checking every letter.

5. Enforce Strong, Unique Passwords and Use a Password Manager

Good password hygiene is still key. Every account – email, online banking, vendor logins – should have a strong, unique password (avoid “Password123” or reuse across sites).

Why it matters: Reused or weak passwords are a chronic SMB problem. A 2022 survey found 65% of people reuse passwords for work. Once one password is stolen, crooks try it everywhere. In fact, 80% of all hacking incidents involve compromised credentials. A single weak password can allow attackers to access your email or other accounts directly.

How to do it:

• Set a policy: Require passwords to be long (at least 12 characters) and complex (mix letters, numbers, symbols). Avoid obvious words or personal info.

• Use a manager: Install a password manager (like Bitwarden, LastPass, or the built-in options in browsers) so employees don’t have to memorize or write down many passwords. These generate and store strong passwords for you.

• Change defaults: Ensure any device or account (like Wi-Fi routers, IoT devices, or old software) isn’t using default passwords that everyone knows.

• Regular updates: Ask employees to update passwords periodically and never share them over email or text.

• Account recovery: Secure account recovery options (like backup email or phone), also with strong passwords or MFA, so attackers can’t reset your accounts.

Teaching and enforcing good password practices is a basic but crucial step. With most breaches involving password theft, this advice alone greatly improves email security.

6. Keep All Software and Devices Updated

Whether it’s your email client (Outlook, Thunderbird, Apple Mail) or the operating system (Windows, macOS), always install updates and patches promptly. This includes phones and tablets if employees check email on them.

Why it matters: Cybercriminals often exploit known vulnerabilities in software. An out-of-date system is like an unlocked door. Attacks can come through things like malicious email attachments that take advantage of an old program bug. By staying updated, you close those holes.

How to do it:

• Automate updates: Enable automatic updates for your OS and email software. Many devices allow scheduling “install updates outside work hours.”

• Patch management: For critical systems (email servers, company laptops), consider a monthly “patch day” to apply updates.

• Email clients: If you use a desktop email program, ensure it’s the latest version. Some older email programs may no longer support modern security features.

• Check mobile: Many people read work email on smartphones or tablets. Make sure those devices’ software stays current (e.g., iOS and Android updates).

• Third-party apps: Any add-on or plugin (calendar, contact manager, file sync) that interacts with email should also be kept updated.

Staying patched is a fundamental security practice. It’s non-technical to do (just click “update”), but it prevents many attacks from ever happening.

7. Backup Important Emails and Data

Even with all precautions, data loss can happen. Ransomware or accidental deletions can lock you out of your email system. Always maintain backups of important email data and attachments.

Why it matters: Small businesses can suffer for months if critical emails (invoices, client records, contracts) are lost. Shockingly, 75% of SMBs say they couldn’t stay in business after a ransomware attack, often because backups were missing. By keeping recent copies of email archives, you ensure the show goes on even if something goes wrong.

How to do it:

• Email archiving: Use built-in email backup or archiving services. Many providers (Exchange Online, Google Vault) can archive every email automatically. Make sure the archive can restore emails if needed.

• Cloud backup: If you use a cloud email system, check if the vendor includes backup snapshots. If not, consider a backup add-on or third-party backup service that can restore your mailbox state.

• Local backups: For on-premises email servers, regularly back up the mail database and test restoration on a spare machine.

• Document important emails: For mission-critical messages (like legal agreements or VIP orders), save copies in a separate file storage or print them to PDF. This can be as simple as forwarding them to a secure file-sharing account.

• Test restores: Periodically, do a “test restore” of some emails to ensure your backup process is working.

Good backups mean that one phishing attack or hardware failure doesn’t ruin your business. When your data is safe, you can recover quickly from cyber incidents.

8. Encrypt Sensitive Emails

When emailing highly sensitive information (financial data, personal details, medical info), use encryption whenever possible. This means the message is locked, so only intended recipients can read it.

Why it matters: If confidential data is intercepted, encryption keeps it unreadable. Despite this, most SMBs don’t encrypt email. In fact, only 17% of small businesses encrypt data, meaning the vast majority send messages that could be exposed. Regulations (like HIPAA or GDPR) may require encryption for certain data. Encryption protects privacy and builds trust.

How to do it:

• TLS (in transit): Ensure your email provider uses SSL/TLS encryption to send messages. This is usually automatic (look for “https://” and the padlock icon in webmail). It encrypts email in transit.

• End-to-end: For extra protection, use built-in encryption tools. For example, Microsoft 365 has an “encrypt” option, and Gmail can use S/MIME if configured.

• Secure portals: If encryption setup is hard, use secure file-sharing instead of email for very sensitive documents. Many vendors provide password-protected sharing links (avoid emailing confidential spreadsheets directly).

• Phone check: Encourage verifying by phone if highly private info must be sent. For instance, call the accountant instead of emailing a full financial statement.

Adding encryption is especially important as attackers get better at intercepting and fabricating messages with AI. Even a basic level of encryption for key documents keeps your SMB compliant and more secure.

9. Develop Clear Email Policies and Incident Plans

Having good email policies and procedures helps everyone on your team know what to do. This includes written guidelines and a plan for when things go wrong.

Why it matters: Without rules, people may use email insecurely by default. For example, an employee might click a link without thinking or reply with confidential information accidentally. Policies help prevent mistakes. And if a breach or suspicious email does happen, a quick plan keeps the damage small.

How to do it:

• Email Use Policy: Write a simple policy (1–2 pages) that explains: no sharing of passwords, what to do if a phishing email arrives (e.g., forward it to IT and delete it), and which sites or attachments are off-limits.

• Acceptable Use: Define what constitutes acceptable email behavior (e.g., no confidential data in personal email, no unknown attachments).

• Incident Response: Set a procedure for reporting and responding to email incidents. For example, instruct staff that if they suspect they clicked a phishing link, they should immediately disconnect from the network and alert IT.

• Regular review: Update these policies at least yearly or when threats change. Remind employees of policies in meetings or newsletters.

Clear policies turn good advice into everyday habits. They also support training – employees have written guidelines to consult. When everyone knows the rules and the reporting steps, your team can respond faster to threats and keep your business running smoothly.

10. Consider Managed Email Security (Outsource the email security best practices to Experts)

Finally, small businesses don’t have to do these alone. A managed email security service can handle many of the above tasks for you. Answerssy, for example, specializes in SMB email protection, offering outsourced monitoring, filtering, and training support.

Why it matters: SMBs often lack dedicated IT security staff, or if they have one, most of the time, the IT employees don't have dedicated email security expertise. Answerssy and similar providers keep up with the latest email threats (like the newest AI-driven scams) so you don’t have to. They can take over routine tasks like checking spam logs, tuning filters, and sending phishing tests. This frees you to focus on your business.

How to do it:

• Research providers: Look for companies with experience securing small business email. Answerssy offers 24/7 email threat monitoring and can tailor solutions to your needs.

• Ask for a trial or assessment: Many services (including Answerssy) offer a free security checklist or consultation. They will evaluate your current setup and show you easy fixes.

• Ongoing support: With managed email security, you get continuous updates and reports without lifting a finger. The service keeps your SPF/DKIM/DMARC records correct, enforces policies, and responds if an attack is detected.

Outsourcing is cost-effective for many SMBs. It’s like having an email security team on call. Combining a managed service with your in-house practices (like training and policies) gives you the best protection in 2025’s complex threat landscape.

Secure Your Business Email in 2025:  By following these 10 best practices – from enabling MFA and SPF/DKIM/DMARC to training staff and using backups – your SMB will be much better protected against email threats. Remember, hackers keep getting smarter with AI and deepfakes, so staying vigilant is key. If you need guidance or a quick security checkup, Answerssy can help. They provide free SMB email security checklists and consultations to make sure your defenses are solid. Don’t wait for a breach – take action today and keep your business email safe and secure.