Email Protection: All You Need To Know (2025)

Email protection is a central issue for any organization, as the risks to business are high. The majority of cyberattacks begin with email campaigns and it still serves as the primary attack vector for cybersecurity threats targeting critical infrastructure organizations in 75% of cases¹. The average cost of a data breach is also globaly increasing, reaching $4.88 million in 2024², highest total ever.

Small and medium businesses face particular challenges in email security, cyber-attacks targeting small businesses in 43% of cases³. The financial impact is substantial, with an average data breach cost for small businesses (less than 500 employees) reaching $2.98 million in 2023⁴.

In 2024, the sectors most targeted by data threats worldwide were:

Email attacks are constantly evolving, and have long been more than just spam. Sophisticated techniques now combine social engineering, artificial intelligence and advanced malware to bypass the defenses put in place by organizations. The rise of remote working has also considerably expanded the attack scope, creating new vulnerabilities that traditional security measures struggle to overcome.

Choosing the right email security for your business requires a comprehensive understanding of protection strategies. From advanced authentication protocols to employee training, organizations need to implement comprehensive security measures to protect their communications.

This guide details the essentials you need to know about email protection, from most common threats to the defensive tools that help secure your organization’s email communications while complying with regulatory requirements.

What is Email Protection?

Email protection is a set of security measures and technologies put in place to defend electronic communications against unauthorized access, data breaches and malicious threats. This security framework acts as a shield, filtering incoming and outgoing messages to protect sensitive information transmitted via corporate messaging systems.

Modern e-mail protection systems operate on several levels of security, starting with basic spam filtering and extending to sophisticated real-time threat detection tools. These tools analyze message content, sender behavior and attachment properties to identify potential risks before they reach end-users. The implementation of an optimum e-mail protection results in an average 85% reduction in security incidents compared with a basic protection system⁵.

E-mail protection is also essential in terms of regulatory compliance. Healthcare organizations, for example, need to secure Protected Health Information (PHI) transmitted by e-mail under HIPAA regulations. Similarly, financial institutions need email security measures that comply with SEC or FINRA requirements. Other US state-level or more global regulations may also apply, such as European Union’s GDPR, which imposes strict controls on European citizens’ personal data transmitted in email communications.

The development of remote working has also expanded the scope of email protection requirements. With employees accessing company e-mail from a variety of locations and devices, security measures must adapt to secure communications over diverse networks while maintaining operational efficiency. This calls for flexible, comprehensive e-mail protection strategies that balance security and responsiveness.

What are the Most Common Threats to E-mail Security?

Here is a comprehensive list of the most common threats to email security in 2025:

PHISHING AND SOCIAL ENGINEERING

Phishing is a form of social engineering using e-mails to trick people into sharing sensitive data, downloading malware or otherwise exposing themselves to cybercrime. Unlike other cyberattacks that directly target networks and resources, a phishing attack uses human error, false stories and pressure tactics to manipulate victims and damage their organization.

There are 3 ways to be affected by a email phishing attack: it can happen when user clicks on a fake link/URL, downloads a malicious attachment or scans a corrupted QR code contained in an email.

There is a significant increase in phishing attempts using QR codes, as those have become much more prevalent and trusted by users. It represents a unique challenge for security providers as they appear as an image during mail flow and are unreadable until rendered. QR Code Phishing accounted for 24% of attacks in 2024⁶.

What is Email Impersonation?

An email impersonation attack occurs when a hacker imitates a legitimate sender’s email address to make a message appear to come from a trusted source.

Impersonating legitimate companies is a basic phishing technique used to gain the trust of victims. It represents a risk both to customers and to the reputation of the business.

In 2024, most phishing attacks have focused on impersonating software brands and online services. Attackers prioritized these targets since gaining access to one account often provides entry to multiple connected services, including email, social networks, and online shopping platforms. In the future, the widespread use of multi-factor authentication and passwordless solutions should gradually reduce the effectiveness of these type of phishing attempts.

Phishing examples:

MALWARE

The term “malware” refers to software code or computer programs (ransomware, Trojans, worms, spyware, etc.) designed to harm computer systems or their users. Almost all modern cyberattacks involve malwares, which can take a large range of forms, from highly damaging and costly ransomware to simple, annoying adware, depending on the cybercriminals’ objective.

The most common techniques for installing malware on a computer remain phishing and social engineering. Email-based malware enters systems through infected attachments or embedded links to :

• hold devices, data or your entire network hostage
• gain unauthorized access to your sensitive data or digital assets
• steal login credentials, intellectual property or any valuable info
• disrupt critical systems on which your business depends

Since 2013, malwares have been spreading exponentially. The AV-Test Institute estimates that there were over 1 billion malware programs in circulation in 2024 and 560,000 new malware programs are detected every day. The speed at which malwares are spreading worldwide is terrifying, anti-malware institutes recording every day new programs they find in their databases.

Most Common Malware Types

There are numerous sophisticated tools designed to compromise email protection and steal sensitive data. Each type of malware serves distinct purposes in a cyber attack, from system infiltration to data theft and extortion.

• Stealer: Stealers are types of malware designed to gain unauthorized access to user information for transfer. This category of malware includes different types of programs that focus on a particular type of data, mainly files, passwords and crypto-currencies. Stealers are able to spy on their targets by recording keystrokes or taking screenshots. They are mainly distributed as part of phishing campaigns.
• Loader: A loader is a malware capable of infecting victims’ computers, analyzing their system information and installing other types of threats, such as Trojans or stealers. Loaders are usually spread via e-mails and phishing links, relying on social engineering to entice users to download and run programs. They use advanced evasion and persistence tactics to avoid detection.
• RAT: Remote Access Trojans (RATs) are malware designed to establish full or partial control over infected computers. These programs often have a modular design, offering a wide range of functionalities for carrying out illicit activities on compromised systems. They are often distributed via e-mails and phishing links.
• Ransomware: Ransomware is a malicious code that blocks access to an organization’s computer or files by encrypting them and demanding payment of a ransom in exchange for decrypting the data. Ransomware can infiltrate after opening a fraudulent attachment or malicious link received by email, while browsing compromised sites or following an intrusion on the computer system. In most cases, it exploits known software vulnerabilities whose patches have not been updated by victims.
• Keylogger: A keylogger (or keystroke logger) is a form of malware that runs in the background of a computer (or other device) to collect a user’s keystrokes. It collects the information and sends it to a hacker via a command and control (C&C) server. The hacker then analyzes the keystrokes to identify valuable information (usernames or passwords) before using them to hack into otherwise secure systems.
• Adware: The term “adware” stands for advertising supported software. Often embedded in freeware downloads or applications, it is a type of malware secretly installed on a computer to display unwanted ads and pop-ups. Adware collects browsing data and can even record keystrokes.
• Exploit: An exploit is a type of malware that takes advantage of a system’s bugs and vulnerabilities to steal data or install other malware. These vulnerabilities are hidden in the code of an operating system or its applications, ready to be discovered and exploited by cybercriminals. A zero-day exploit is a software vulnerability for which there is currently no defense or patch available.
• Backdoor: A backdoor is a code used to provide unauthorized remote access to an infected computer by exploiting system vulnerabilities. It runs in the background and does not appear in running software. Most backdoors need to be installed on a computer in one way or another, but some do not need to be installed at all, as parts of them may already be integrated into software that works with a remote host. Programmers sometimes leave these backdoors in their software for diagnostic or troubleshooting purposes, and hackers use them to penetrate a system.
• Trojan: A Trojan is a type of malware that downloads onto a computer, disguised as a legitimate program. Usually hidden as an attachment in an e-mail or a free file download, then transferred to the user’s system, its installation relies on social engineering to trick the user into gaining backdoor access to corporate systems, spying on users’ online activity or stealing sensitive data.
• Rootkit: A rootkit is a type of malware designed to enable hackers to take control of a target computer or network. It sometimes takes the form of a single piece of software, but more often consists of a collection of tools that allow administrator-level control over the target device. The most common techniques for installing a rootkit on a computer are phishing and social engineering.

Apart from exploit, malware intrusion into a system most often relies on phishing or social engineering techniques, and emails remain the main entry point in most cases.

Malware examples:

• Sparkling Pisces Unleashes New Malware: KLogEXE and FPSpy
• Malicious Ads and Phishing Emails Used to Distribute RomCom Malware

RANSOMWARE ATTACKS

Ransomware is a specific type of malware that holds an organization’s sensitive data or network hostage by threatening to keep it locked, or worse, to obtain a ransom payment. It corrupts email systems through malicious attachments or links that download encryption software.

Ransomware is one of the most common types of malware, and these cyber-attacks can cost businesses millions of dollars. In 2023, 20% of all cyber-attacks recorded involved ransomware.⁷

In 2024, 5 ransomware groups accounted for 51% of attacks and the most prevalent initial access techniques continue to be social engineering⁸.

Ransomware examples:

• US Healthcare Organizations Targeted by New Interlock Ransomware Group
• Storm-0501 Threatens Hybrid Cloud Security with Ransomware Attacks

BUSINESS EMAIL COMPROMISE (BEC)

Busines Email Compromise (BEC) is a spear phishing e-mail scam designed to steal money or sensitive data from an organization. In a BEC attack, a cybercriminal sends e-mails to employees of a target company, posing as a colleague, supplier or other trusted entity. These e-mails are written in such a way as to induce employees to pay fraudulent invoices, make bank transfers or divulge company-sensitive information.

Business e-mail compromise attacks are among the most costly cyberattacks for organizations. In 2022, they represented the second most expensive type of breach, with an average cost of $4.89 million.⁹

According to Microsoft engineers, BEC attackers most frequently alter inbox rules (40% of incidents), followed by internal phishing attempts and email thread infiltration (each at 25%). Multi-factor authentication (MFA) tampering accounts for 10% of documented cases. These statistics also demonstrate how attackers often maintain persistent access after breaching business email accounts.

Business Email Compromise attacks have evolved through sophisticated methods including inbox rule manipulation via API calls, lateral movement within organizations, and conversation thread infiltration. Attackers now employ UpdateInboxRules commands to redirect sensitive emails, compromising multiple accounts at the same time. Recent attack patterns show the misuse of legitimate applications (like PerfectData Software and eMClient) for mailbox theft, along with stealthy “low and slow” approaches where attackers read minimal emails daily to avoid detection. The attacks often target specific departments with customized phishing campaigns in local languages, particularly focusing on IT, finance, and legal teams.

BEC examples:

• FBI Announcement on BEC Scams Reveals Losses Up to $43 Billion

EMAIL ACCOUNT COMPROMISE (EAC)

Email Account Compromise (EAC) is a common name used to refer to BEC attacks, but although the two are related, it doesn’t quite mean the same thing. EAC is a specific type of business e-mail compromise in which attackers hijack a legitimate e-mail account to gain unrestricted access to its inbox and contacts.

EAC occurs when attackers gain unauthorized access to email credentials through password theft, phishing/social engineering, brute force attack or malware. Compromised accounts enable attackers to access sensitive communications, launch internal attacks, and steal confidential data.

MAN-IN-THE-MIDDLE (MitM) ATTACKS

An Man-in-the-Middle attack is a cyberattack in which a hacker steals sensitive information by eavesdropping on communications between two online targets, such as a user and a web application. Vulnerabilities in networks, web browsers, e-mail accounts, security protocols and user behavior are the starting point for this type of attack. Cybercriminals exploit these weaknesses to interpose themselves between users and trusted applications in order to control communications and intercept data in real time.

MitM attacks can intercept email communications between senders and receivers, particularly in remote work environments. Attackers position themselves within the email traffic flow to intercept sensitive data such as credit card numbers, account information and login credentials. They then use this information to commit other cybercrimes (unauthorized purchases, hijacking of financial accounts, identity theft).

How does MitM Attack happen?

MitM attacks exploit vulnerabilities in Wi-Fi networks, public access points or even compromised websites. The tactics most commonly used by attackers are :

• Address spoofing (ARP Spoofing): Exploiting the Address Resolution Protocol (ARP) to trick an employee’s device into sending data instead of the legitimate recipient.
• DNS Spoofing: Manipulation of DNS servers to redirect employees to fake websites identical to the real ones, in order to capture their login credentials or other sensitive information.
• Evil twin: Creation of malicious Wi-Fi access points that look legitimate because their names are similar to those of nearby companies or reliable public connections, in order to intercept user data.

ACCOUNT TAKEOVER (ATO)

Account takeover fraud (ATO) is a form of identity theft where scammers overtake an online account and pose as real users. It occurs when malicious actors gain unauthorized access to email accounts through compromised credentials credentials, session hijacking, social engineering or device takeover.

This type of threat operates in two stages: first, attackers obtain login credentials through phishing, password spraying, or purchasing stolen data. Then, they exploit the compromised account to conduct internal reconnaissance, send fraudulent messages, or access sensitive information stored in mailboxes. Once inside, attackers often create forwarding rules or hidden folders to maintain long-term access.

While financial institutions were historically the most concerned about account takeover, today any organization that has a user account or membership system is vulnerable. The motivation behind these attacks is most often financial, as cybercriminals generally seek the quickest and easiest means of financial gain. This can be achieved by selling personal information, stealing crypto-currency or tricking victims into installing ransomware.

ATO is one of the most damaging cyber threats an organization can face. Without prevention, these attacks not only threaten your sales and revenues, but also your brand reputation and cause a loss of your customers’ trust.

SPAM

Unsolicited email sent in large numbers to mailboxes for advertising or commercial purposes, spam floods inboxes and disrupt business operations. Modern spam campaigns employ artificial intelligence to generate convincing content that bypasses traditional filters. These messages also often contain hidden malicious elements, from tracking pixels to credential harvesting links.

In December 2024, China and the USA were the countries with the highest average number of spam emails sent in one day worldwide, at around 7.8 billion.

More infos:

• Spam Filtering Service
• MSP Spam Filtering Services

What Are the Best Practices for Securing Enterprise Email Communications?

Implementing efficient email security within your organization requires a multi-layered approach combining technology, user awareness, and process controls.

Strengthen Employee Education and Awareness

Security awareness training forms the foundation of any email protection strategy. It should focus on threat recognition, safe email practices, and incident reporting procedures. Training simulations expose employees to realistic attack scenarios, building practical defense skills. This includes learning to identify phishing attempts, proper handling of sensitive data, and understanding authentication procedures.

Regular training help employees recognize suspicious patterns in sender addresses, message content, and attachment types, while establishing proper channels for reporting potential security incidents.

Implement Antivirus Protection with Sandboxing Capabilities

Antivirus tools scan email attachments and links for known malware signatures and suspicious behaviors. Advanced scanning engines analyze file characteristics, code patterns, and runtime behaviors to detect both known threats and previously unseen malicious code variations.

On the other hand, sandboxing technology executes potentially dangerous files in isolated environments to observe their behavior. The isolated testing environment prevents potential malware from accessing production systems while allowing security teams to safely analyze its intended actions.

Combined, these technologies create a efficient defense against zero-day threats and polymorphic malware that escape traditional detection methods.

Enforce Password Security with Multi-Factor Authentication (MFA)

Managing email passwords is often a critical point for organizations, as much as it is an entry point for many threats. A strong password policy should set minimum requirements for length, complexity, and regular updates, while preventing password reuse across accounts. Passwords must be regularly changed and compromised credentials constantly monitored.

Multi-factor authentication is an effective tool for protecting against password threats. MFA adds critical protection layers to email access by requiring multiple verification methods beyond passwords. This security measure combines something users know (password), something they have (mobile device), and something they are (biometrics).

Apply Email Encryption Standards for Data Protection

Email encryption protects message confidentiality during transmission and storage through multiple security layers. End-to-end encryption ensures only intended recipients can access sensitive content, while Transport Layer Security (TLS) secures communications between email servers.

Organizations must implement encryption policies based on message content and recipient classification. Message signing verifies sender authenticity and prevents tampering. Strong encryption measures save significantly on data breach costs. For example, encrypted data at rest and in transit reduces the risk of breaches, contributing to lower remediation costs.

Select Advanced Security Solutions for Your Email Infrastructure

AI and machine learning capabilities are now essential components of advanced email security solutions, significantly improving detection rates for sophisticated threats.

Modern security solutions combine machine learning and behavioral analysis to detect sophisticated threats. Secure email gateways must filter malicious content before it reaches inboxes, while cloud-based platforms adapt more quickly to emerging attack patterns. These solutions also incorporate sandboxing technology to safely analyze suspicious attachments and URLs.

Prevent Data Loss (DLP)

Data is vulnerable wherever it is stored, making information protection a top priority for any organization, as the cost of a failure can be high. In fact, the average global cost of a data breach rose by a further 10% in 2024.¹⁰

Data Loss Prevention (DLP) is the discipline of protecting sensitive data from theft, loss and misuse, using cybersecurity strategies, processes and technologies. DLP helps prevent leakage and loss of an organization’s data by tracking data flows across the network and applying appropriate security policies. It ensures that only authorized people can access data, and for the right reasons.

DLP systems protect corporate data by identifying sensitive information, then using in-depth content analysis to detect and prevent potential data leaks. They monitor and control email content to prevent unauthorized sharing of sensitive information. These solutions scan outbound messages for protected data patterns including credit card numbers, social security numbers, and intellectual property…

Advanced DLP employs contextual analysis to understand data usage and enforce granular policies. Machine learning helps identify anomalous email behavior that might indicate data theft. Organizations can so implement automated encryption or blocking based on content classification. This combination of scanning, analysis and automated enforcement helps to protect sensitive data from both accidental exposure and malicious exfiltration attempts.

Set Email Authentication Standards

Email authentication is a critical component of email security, based on different protocols, to verify sender legitimacy and message integrity. These protocols authenticate the origin of an email, ensuring that only authorized servers can send messages on behalf of a domain, thereby enhancing trust and reducing security risks in email ecosystems. SPF defines authorized sending servers, while DKIM adds cryptographic signatures to detect tampering. DMARC enforces handling policies for messages failing authentication. These elements work together to prevent email spoofing, phishing, and other email threats.

Develop Security Monitoring Practices

Security monitoring identifies suspicious email patterns and potential compromises and refers to SIEM – for Security Information Management (SIM) and Security Event Management (SEM). It collects all information flows from hundreds of data sources, from host systems and applications to the network and security devices such as firewalls and antivirus filters.

Security teams then exploits Machine Learning algorithms to normalize the data, correlate it and detect incidents and events indicative of a threat. Real-time alerts notify administrators of high-risk activities such as mass forwarding rules or unusual access patterns. Security monitoring thus offers rapid detection, investigation and remediation of the widest range of security threats.

Ensure Regular Security Assessments

Email security requires periodic evaluation of controls and configurations. Security teams must conduct regular penetration test to identify vulnerabilities in email infrastructure. Security assessments should cover authentication settings, encryption protocols, and access controls. Configuration audits ensure security policies align with business requirements and compliance standards.

Regular security assessments help identify misconfigurations and security gaps before they can be exploited by attackers.

What Should You Consider When Choosing an Email Protection Solution for Your Business?

Email protection selection depends on your organizational needs, threat exposure, and compliance requirements. Security solutions must integrate with existing infrastructure while providing comprehensive threat coverage.

Key Factors When Choosing a Business Email Protection

The size of your company and industry regulations shape business email security requirements. Healthcare organizations, for example, must comply with HIPAA, while financial institutions follow SEC guidelines.

Organizational IT resources influence solution complexity. Small teams typically benefit from managed services that reduce operational overhead, while large enterprises maintain dedicated security staff for custom implementations. Security teams must evaluate internal capabilities against solution requirements to ensure sustainable operations.

The design of an email protection infrastructure is crucial to the effectiveness of the security solution implemented. The volume of e-mail and the number and geographical distribution of your users have a major impact on these architectural decisions. In particular, the volume of data processed determines bandwidth requirements – with cloud solutions consuming 15-25% of available bandwidth during peak periods.

The budgetary costs to evaluate when deploying an email security solution go beyond simply integrating email security tools into your business; they also include employee training and maintenance costs. According to Statista, businesses worldwide spend an average of 12% of their IT budgets on cybersecurity¹¹.

Choosing Between Cloud Versus On-Premise Solutions

Email security deployment models balance control requirements with operational efficiency. Cloud solutions provide rapid updates and reduced infrastructure costs, while on-premise deployments offer enhanced data control.

Cloud platforms offer continuous threat intelligence updates and high availability, while typically requiring lower implementation and maintenance costs compared to on-premise solutions. Organizations must evaluate these factors alongside their specific security and compliance requirements when choosing between deployment models.

Email Security: our Key Elements to Remember

Email protection requires a comprehensive approach integrating technology, processes, and employee awareness. The constant evolution of threat types also requires organizations to adapt regularly their security measures against ever more sophisticated attacks. The financial impact of these attacks continues to grow, with the global average cost of a data breach reaching $4.88 million in 2024¹².    

Effective e-mail security requires a technical architecture tailored to your business, based on several fundamental elements:

• Advanced threat detection, notably using machine learning and behavioral analysis, is a first line of defense.
• Strong authentication protocols and encryption protect your sensitive communications from unauthorized access.
• Regular security audits ensure that controls remain effective in the face of new threats.

Employee awareness remains essential, as human factor often determines the success or failure of e-mail attacks. Organizations need to promote a culture of security through ongoing training and by establishing clear alert protocols.

Choosing a security solution for your e-mail requires a careful evaluation of your organization’s needs, resources and compliance requirements. You need to find a balance between protection capabilities and the specific requirements of your business, without penalizing your operational efficiency.

The choice between on-premise or cloud email protection will affect both your organization’s security capabilities and operational flexibility. Cloud-based solutions offer rapid scalability and automatic updates, while on-premise installations give you greater control over your data and your company’s internal security processes.

As email threats are constantly evolving, with new types of actors and tools, your email security ecosystem must always be able to adapt and regularly update its defense strategies. In fact, the choice of an integrated protection solution or one delegated to a service provider must also be assessed in the light of this need for rapid adaptation. 

Image credits: Theeranan, Supatman, TechTonic, Foyez Ullah, NongAsimo; AdobeStock

1. OPSWAT; 2024 Osterman Report ↩︎
2. IBM; 2024 Cost of a Data Breach Report ↩︎
3. U.S. Small Business Administration / Accenture; State of Cyber Resilience 2023 Report ↩︎
4. IBM; 2023 Cost of a Data Breach Report ↩︎
5. Proofpoint; 2024 State of the Phish Report ↩︎
6. Microsoft; 2024 Digital Defense Report ↩︎
7. IBM; 2024 IBM X-Force Threat Intelligence ↩︎
8. Microsoft; 2024 Digital Defense Report ↩︎
9. IBM; 2023 Cost of a Data Breach Report ↩︎
10. IBM; 2024 Cost of a Data Breach Report ↩︎
11. Statista; Companies IT budget allocated to security worldwide ↩︎
12. IBM; 2024 Cost of a Data Breach Report ↩︎