Email security in the workplace: 8 building blocks for SMEs

Email security protects businesses from phishing, spoofed senders, malware, account takeovers, and data loss via business emails. It consists of more than just a spam filter; it comprises multiple layers of protection: sender authentication, malware and link protection, multi-factor authentication (MFA), secure policies, encryption, awareness, and recovery.

Email is particularly critical for small and medium-sized enterprises (SMEs) because offers, invoices, payment approvals, customer data, and internal communication all flow through this channel daily. Attackers exploit this vulnerability. They impersonate suppliers, executives, or well-known services to steal login credentials, redirect payments, or introduce malware.

This article demonstrates which measures are truly essential, why a spam filter alone is insufficient, and how businesses can systematically improve email security using eight key building blocks. The focus is on practical measures for Microsoft 365 environments, SMEs, and mid-sized organizations.

Table of contents

• What does email security mean?
  
• Why is email security so important for businesses?
• Why is a spam filter alone no longer sufficient?
• What types of attacks typically use email?
• The 8 building blocks of modern email security
• SPF, DKIM, and DMARC explained simply
• Email encryption, TLS, and DLP
• Email security in Microsoft 365
• Internal or external email security?
• Conclusion
• Email security FAQ

What does email security mean?

Email security encompasses all technical and organizational measures that protect business emails from phishing, spoofing, malware, fraud, data leaks, and unauthorized access. The goal is to identify dangerous messages, secure user accounts, and ensure the controlled transmission of sensitive information.

Email security comprises several layers. Technically, it involves filters, link protection, attachment verification, sender authentication, encryption, DLP (Data Loss Prevention), MFA (Multiple Authentication), and logging. Organizationally, it involves clear approval processes, reporting channels, awareness, defined responsibilities, and regular reviews of security measures.

An effective security concept therefore not only addresses which emails should be blocked. It also defines how to handle suspicious messages, how to detect compromised accounts, and how companies can resume secure operations after an incident.

For Austrian companies, onlinesicherheit.gv.at offers helpful information on phishing, fraud attempts, and how to respond to suspicious emails.

Why is email security so important for businesses?

Email is one of the most important entry points for cyberattacks. The reason is simple: emails connect external communication, internal shares, identities, and files in a single channel. Anyone who compromises a mailbox can often access other systems or misuse trusted communications.

Attacks that appear technically innocuous are particularly dangerous. A forged payment order, a manipulated invoice, or an email from a compromised legitimate supplier doesn't necessarily contain malware. Nevertheless, the damage can be substantial.

Typical consequences of inadequate email security include:

• Stolen login credentials
• Compromised Microsoft 365 accounts
• Manipulated invoices or payment data
• Data leaks from mailboxes
• Malware or ransomware infections
• Misuse of internal communications
• Loss of trust among customers and partners
• Business interruptions following security incidents

Email security is therefore not just an IT issue. It affects management, accounting, sales, HR, and all employees who regularly communicate with external contacts.

Especially in Microsoft 365 environments, email security should always be considered in conjunction with identity protection, endpoint security, and backups. Otherwise, a compromised mailbox can quickly lead to further problems in OneDrive, SharePoint, Teams, or on end devices.

Why is a spam filter alone no longer sufficient?

A spam filter is important, but not sufficient on its own. Modern attacks bypass traditional filters because they are specifically designed, originate from genuinely compromised accounts, or contain no dangerous attachments. Email security must therefore combine multiple layers of protection.

A spam filter primarily detects known patterns, suspicious senders, poor reputation, and typical mass campaigns. However, many of today's attacks are more personal. Business email compromise, CEO fraud, or supplier fraud often work without malware. The email appears legitimate and requests a specific action: authorizing a payment, changing bank details, opening a file, or confirming access.

Therefore, modern email security also requires:

• Sender authentication with SPF, DKIM, and DMARC
• Protection against phishing and spoofed domains
• MFA for user accounts
• Rules against automatic redirects
• Secure link and attachment verification
• Processes for payment approvals
• Awareness and easy reporting channels
• Monitoring of logins and mailbox rules
• Recovery and incident response processes

The most important point: Technology and processes must be aligned. A dangerous email can be blocked. However, a credible fraudulent request must also be intercepted through organizational measures, such as the four-eyes principle or mandatory callbacks in case of payment changes.

What types of attacks typically occur via email?

The most common email attacks on businesses are phishing, business email compromise, spoofing, malware, fake invoices, and account takeovers. While they differ technically, they usually pursue the same goal: access credentials, money, data, or control over systems.

Phishing

Phishing aims to trick users into revealing login credentials or opening malicious links. The emails often impersonate well-known services, banks, parcel delivery services, Microsoft 365, tax portals, or internal notifications.

Effective countermeasures against phishing include multi-factor authentication (MFA), secure login policies, link protection, anti-phishing policies, awareness training, and clear reporting procedures. It is particularly important that employees can easily report suspicious emails without fear of being blamed.

Business Email Compromise and CEO Fraud

Business Email Compromise (BEC) is particularly dangerous because the attack often works without malware. Attackers impersonate executives, suppliers, or business partners and attempt to manipulate payments or processes.

Typical warning signs include:

• unusual urgency
• requests for confidentiality
• changed bank details
• new payment instructions
• deviations from the normal approval process
• private or unusual communication channels
• minor discrepancies in the sender's domain or signature

BEC cannot be prevented solely through technical means. Companies need clear processes: Payment changes must be confirmed via a second channel, ideally using known phone numbers and established approval procedures.

Spoofing and fake senders

Spoofing involves forging a sender address to make an email appear trustworthy. This is particularly critical when using a company's own domain. If attackers can send emails in the company's name, the domain's reputation suffers.

SPF, DKIM, and DMARC help significantly reduce spoofing. However, proper implementation is crucial. Many companies have SPF configured but lack comprehensive DMARC monitoring or a consistent policy.

Malware and dangerous attachments

Malware wird häufig über Office-Dokumente, Archive, Links zu Downloadseiten oder kompromittierte Cloud-Freigaben verbreitet. Moderne Schutzmaßnahmen prüfen Anhänge dynamisch, analysieren Links zum Klickzeitpunkt und blockieren riskante Dateitypen.

Ergänzend zur E-Mail-Ebene braucht es Endpoint Security. Wenn eine gefährliche Datei trotz Filter geöffnet wird, muss der Endpunkt verdächtiges Verhalten erkennen und stoppen.

Malware is often spread via Office documents, archives, links to download sites, or compromised cloud shares. Modern protection measures dynamically scan attachments, analyze links at the time of clicking, and block risky file types.

In addition to email protection, endpoint security is essential. If a dangerous file is opened despite a filter, the endpoint must detect and stop this suspicious behavior.

The 8 building blocks of modern email security

Modern email security consists of several components. For SMEs, it's important not to overcomplicate the measures, but rather to first reduce the greatest risks: phishing, account takeovers, spoofing, BEC, and malware.

Checklist: 8 building blocks of modern email security

These building blocks work best together. A single product does not completely solve the problem. It is crucial that protective measures are regularly checked, documented and adapted to new risks.

Technical protective measures

Technical security measures form the first line of defense. These include anti-spam, anti-malware, URL protection, attachment scanning, sandboxing, quarantine workflows, and sender authentication.

It is crucial that quarantine and approval processes are clearly defined. If dangerous emails are blocked, but employees can approve them themselves without review, a new risk arises. Conversely, security measures should not unnecessarily disrupt daily operations.

Identity and access protection

Many email attacks target the user account, not the message itself. Therefore, multi-factor authentication (MFA) is essential. A stolen password should not be enough to access a mailbox.

Recommended measures include:

• MFA for all users
• Stronger security for administrator accounts
• Disabling insecure legacy protocols
• Conditional access
• Inspection of risky logins
• Monitoring of unusual mailbox rules
• Restricting external forwarding
  

Organizational measures

Technology doesn't prevent all fraud. That's why email security requires clear organizational rules. This applies especially to payment authorizations, new bank details, confidential documents, and internal escalation channels.

The following have proven effective:

• Four-eyes principle for payments
• Obligation to call back when bank details have changed
• Clear reporting channels for suspicious emails
• Short awareness sessions
• Defined responsibilities for incidents
• Regular review of exceptions

This is precisely where it becomes clear whether email security truly works in everyday practice. Guidelines, Microsoft 365 policies, and reporting channels must be structured so that employees can recognize suspicious messages, react appropriately, and escalate incidents quickly.

For companies that cannot plan and operate email security measures internally, structured IT support is advisable. FIGULI CONSULTING helps to establish transparent technical protection layers, Microsoft 365 policies, and organizational processes.

Improve your email security with FIGULI CONSULTING

SPF, DKIM and DMARC explained simply

SPF, DKIM, and DMARC are standards for email authentication. They help verify whether an email truly originates from a legitimate source. This significantly reduces spoofing, domain abuse, and forged senders.

SPF

SPF uses a DNS record to specify which mail servers are authorized to send emails on behalf of a domain. This allows receiving mail servers to verify that an email originates from a legitimate source.

SPF helps prevent simple forgery, but it is not sufficient on its own. Problems arise when legitimate third-party providers are missing, forwarding rules don't function correctly, or the SPF record contains too many DNS lookups.

DKIM

DKIM adds a cryptographic signature to outgoing emails. Recipients can verify whether the message has been altered in transit and whether it matches the stated domain.

DKIM is especially important for companies using Microsoft 365, newsletter tools, CRM systems, or external email delivery services. These systems must be properly configured to prevent legitimate emails from being flagged as fraudulent.

DMARC

DMARC combines SPF and DKIM with a clear policy. The domain defines what should happen to emails that fail the check: monitor, quarantine, or reject.

A clean DMARC rollout is carried out in stages:

1. Discover legitimate senders
2. Check SPF and DKIM
3. Start DMARC with p=none
4. Evaluate reports
5. Correct misconfigurations
6. Increase p=quarantine
7. Set p=reject when stable

Microsoft describes SPF, DKIM, and DMARC as core email authentication methods in Microsoft 365.

Email encryption, TLS and DLP

Besides protection against attacks, confidentiality plays a crucial role. Email security must also prevent sensitive data from being sent unencrypted, accidentally, or to the wrong recipients.

TLS

TLS protects the transport connection between mail servers, thus securing the transmission. While TLS is now an important minimum standard, it does not automatically protect the message itself across all stages.

S/MIME

S/MIME enables email signatures and end-to-end encryption. A signature confirms the sender's identity and the message's integrity. Encryption protects the content from unauthorized access.

In practice, S/MIME is particularly relevant when confidential or personal data is regularly sent via email. Proper handling of certificates, validity periods, and key management is crucial.

DLP

DLP stands for Data Loss Prevention. DLP policies identify sensitive content, such as personal data, financial information, or confidential documents. Depending on the policy, emails can be blocked, encrypted, or flagged with warnings.

DLP should be implemented gradually. Too many rules quickly lead to false positives. A pragmatic start with a few critical data types and clear escalation paths is better.

When personal data is processed, technical and organizational measures are also relevant from a data protection perspective. The Austrian Data Protection Authority, in its guidelines for data controllers, refers to suitable measures such as encryption, confidentiality, integrity, availability, and regular audits.

Email security in Microsoft 365

Many SMEs use Microsoft 365 as a central platform for email, files, teams, and identities. This means email security is closely linked to Microsoft 365 security. Crucial factors are not just the license, but also the correct configuration and regular monitoring.

Key measures in Microsoft 365

For Microsoft 365 environments, the following are particularly important:

• MFA for all users
• Conditional Access
• Disabling legacy authentication
• Anti-phishing policies
• Safe links and safe attachments
• Quarantine workflows
• Protection against external forwarding
• Monitoring of logins and mailbox rules
• DMARC, DKIM, and SPF for your domain
• Regular policy reviews

Microsoft Defender for Office 365 can extend email security with anti-phishing policies, safe links, and safe attachments. However, its effectiveness depends heavily on correctly configuring policies, controlling exceptions, and regularly addressing alerts.

Even more effective protection and better management are achieved with Hornet Total Security for M365.

Don't forget your Microsoft 365 backup.

Email security doesn't end with protection against attacks. Businesses should also check whether important mailboxes, calendars, contacts, and Microsoft 365 data are recoverable. Deleted or manipulated content can otherwise become a problem, even if the attack is detected.

Since email, OneDrive, SharePoint, and Teams work closely together, the backup strategy should also take these interrelationships into account.

Hornet Security offers a fast and reliable cloud-to-cloud backup solution, which is included in plan 3 or 4.

Internal or external email security?

Whether email security should be managed internally or externally depends on expertise, time, system landscape, and risk. Many SMEs benefit from a hybrid model: business processes and approvals remain internal, while external IT partners provide support with configuration, monitoring, reviews, and incident response.

When internal support is appropriate

Internal support is beneficial if sufficient expertise, time, and backup are available. This requires:

• Experience with Microsoft 365 and email security
• Clear responsibilities
• Regular policy reviews
• Access to relevant logs and reports
• Secure administration
• Defined escalation paths
• Awareness and reporting processes

If any of these elements are missing, security gaps can quickly arise. Unclear responsibilities regarding quarantine, alerts, DMARC reports, and compromised mailboxes are particularly critical.

When external support is useful

External support is beneficial when internal resources are lacking or when the existing environment needs a professional review. An external partner can help prioritize risks, properly configure Microsoft 365 policies, gradually roll out DMARC, and design effective BEC (Business Email Compromise) processes.

A good partner should provide:

• a clear assessment of the current situation
• a transparent list of action items
• detailed documentation
• technical implementation
• regular reviews
• comprehensible reporting
• incident support
• practical recommendations instead of overwhelming users with unnecessary tools

FIGULI CONSULTING helps companies build a structured email security strategy: from Microsoft 365 configuration and DMARC to MFA, backup, and monitoring, all the way to organizational processes to combat phishing and business email compromise.

Conclusion

Email security isn't a single product, but rather a combination of technology, identity protection, processes, and regular monitoring. A spam filter remains important, but it's no longer sufficient against targeted phishing attacks, business email compromise (BEC), spoofing, and account takeovers.

For SMEs, eight key components are crucial: spam and malware protection, URL and attachment verification, SPF/DKIM/DMARC, MFA, conditional access, forwarding protection, clear processes for preventing BEC, and an incident and recovery plan. Consistently implementing these components significantly reduces the greatest risks.

If internal resources lack the time, expertise, or oversight, FIGULI CONSULTING can help you conduct a structured email security review, establish robust Microsoft 365 policies, and implement practical, concrete measures.

Discuss email security with FIGULI

FAQ about email security

What is email security?

Email security encompasses technical and organizational measures to protect business emails. These include spam and malware protection, phishing prevention, sender authentication, multi-factor authentication (MFA), encryption, data loss prevention (DLP), monitoring, and clear processes for handling suspicious messages.

Why is email security important for businesses?

Email security is important because many attacks originate via email. Phishing, spoofing, business email compromise, and malware can lead to account takeovers, data loss, fraudulent payments, and business interruptions.

Why isn't a spam filter sufficient?

A spam filter detects many mass campaigns, but not every targeted attack. Business email compromise, compromised legitimate senders, and fraudulent payment requests often appear technically undetectable. Therefore, additional measures such as MFA, DMARC, established processes, and monitoring are necessary.

What measures protect against phishing?

Multi-factor authentication (MFA), secure login policies, anti-phishing policies, link protection, attachment verification, awareness campaigns, and easy reporting channels help protect against phishing. It is especially important to understand that stolen passwords without two-factor authentication are insufficient to access email accounts.

What is Business Email Compromise?

Business Email Compromise is a targeted email fraud in which attackers impersonate executives, suppliers, or business partners, or use compromised accounts. The goal is usually to redirect payments, manipulate approvals, or obtain confidential information.

What role do SPF, DKIM, and DMARC play?

SPF, DKIM, and DMARC help verify the authenticity of emails. SPF defines authorized sending servers, DKIM signs messages, and DMARC specifies how recipients should handle failed verifications. Together, they reduce spoofing and domain abuse.

How does MFA improve email security?

Multi-factor authentication (MFA) improves email security because a password alone is no longer sufficient for access. Even if login credentials are stolen through phishing, the second factor can prevent or significantly hinder account takeover.

What's important for email security in Microsoft 365?

In Microsoft 365, MFA, conditional access, anti-phishing policies, safe links, safe attachments, DMARC, secure forwarding rules, and regular monitoring are particularly important. It's crucial that these features are configured correctly and continuously reviewed.

How often should email security be reviewed?

Email security measures should be reviewed regularly. Monthly checks of alerts, quarantines, mailbox rules, forwards, and policy changes are recommended. Quarterly reviews should be conducted to assess processes, DMARC reports, exceptions, and awareness measures.