6.EmailConnection Touch

Email is one of the most prominent methods of modern business communication. It acts as a critical dissemination channel for sharing legal documents and other confidential business information in any formal environment. However, email is also the root cause of over 90% of all cyberattacks such as phishing, URL spoofing, malicious attachments, trojans, and malware.

Hackers design these messages to look harmless, but a successful attack can cause severe, lasting damage including data loss, reputational harm, and financial damage to your organization. The impact of data breaches can be devastating for a company. Therefore, it is important to take precautions to help your organization thwart email threats, and use reputable open-source security tools to secure business email. 

This article will explore why the collaborative, transparent open-source development model is a superior vehicle for engineering flexible and effective email protection, as well as offer other tips and best practices Linux users should implement to secure their email.

Common & Costly Email Threats Organizations Face

Email remains a primary way to communicate. However, it is also a target for cybercriminals due to its widespread usage and potential vulnerabilities. Organizations face various email threats that can lead to significant financial losses, reputation damage, and data breaches. To protect sensitive information and avoid risks, companies should understand what they are dealing with.


PhishingPhishing attacks are one of the most popular and damaging email threats. They usually presume that somebody poses as a legitimate entity, such as a bank, government agency, or a well-known brand. The idea is to deceive recipients and obtain sensitive information. Phishing emails often contain persuasive messages that urge recipients to click on malicious links, provide login credentials, or disclose confidential data.

One of the most popular queries in Google concerning this topic is “Phishing vs spear phishing”. While phishing is aimed at a large number of users, a spear phishing attack targets a particular person, a company's CEO, for example. 

Such attacks lead to severe consequences, ranging from financial fraud to data breaches. Once a phishing attack occurs, the business's personal information, financial data, or login credentials may be compromised. Moreover, such attacks can also be used as an entry point for further cyberattacks, such as installing malware or gaining unauthorized access to an organization's network. 


In this type of attack, malicious software encrypts the victim's data, making it inaccessible until a ransom is paid to the attacker. These attacks can have devastating consequences. For instance, a business can face operational disruptions, financial losses, and reputational damage.

Ransomware emails are often disguised as legitimate messages. When one opens the attachment or clicks on a link, the ransomware is activated, rapidly encrypting files and rendering them unusable. In some cases, it can also spread throughout the organization's network, infecting multiple systems. 

Remember: ransomware recovery is often problematic. Therefore, learning how to prevent email threats rather than deal with consequences would be wise.

Business Email Compromise (BEC)

Business CybersecurityBusiness Email Compromise (BEC) attacks specifically target organizations and their employees. Cybercriminals gain unauthorized access to an employee's or a high-ranking executive's email address. They then use these compromised accounts to deceive employees into performing fraudulent actions. Business email compromise examples include manipulations to make people transfer money or disclose sensitive information.

BEC attacks often presume that attackers study an organization or monitor email communications. Doing so helps create convincing messages that trick employees into taking action. 

To address this threat, a company requires a multi-layered approach that combines technological solutions, employee education, and robust security practices. Open-source software provides cost-effective and customizable tools to detect and mitigate these risks. Thus, it c enhances an organization's defenses against email threats. 

Why Is Email Security of Critical Importance for All Organizations?

There are several reasons why email security is vital for all types of companies:

  1. It serves as a primary means of communication for sharing sensitive information and conducting important business transactions. Because of that, it is a prime target for cybercriminals. 
  2. Threats like phishing and ransomware are constantly evolving and becoming increasingly sophisticated. Therefore, they pose substantial risks to organizations regardless of their size.
  3. Data protection regulations and industry standards require strict email security measures to ensure sensitive data's confidentiality, integrity, and availability.

Open Source Utilization in Email Security

The use of open-source software is one of the ways to enhance email security for organizations. These solutions are transparent due to a community-driven approach to software development. 

This way presumes the ability to review and improve the solutions by numerous developers, who keep track of the vulnerabilities and constantly fix them. As a result, open-source software is often more secure and has fewer bugs.

Another benefit of open-source software is its customization. Any user can apply changes and patches to tailor a product to their needs.

Email Security Tips & Best Practices for Linux Users

Generally, Linux is considered to be more secure than other operating systems. Nonetheless, it is essential to implement email security measures to defend against cyber threats. Follow these tips to ensure the confidentiality and integrity of your email communication.

Use End-To-End Encryption (E2EE)

This encryption method ensures that only the intended recipient can decrypt the message. In plain English, only your addressee can read your email. Even when an email is intercepted, it will only be unreadable encrypted data without the appropriate decryption key.

Upon receiving an encrypted email, the recipient's email client uses the private key to decrypt the message, making the content readable. This ensures that even if the email is intercepted during transit or stored on servers, it remains encrypted and inaccessible to unauthorized individuals without the private key.

It is also important to note that for end-to-end encryption to be effective, both the sender and the recipient must have compatible encryption software and exchange public encryption keys securely. For more information, you can check our practical guide to using E2EE on Linux.

Leverage VPN

Another way to enhance email security is to use VPN (Virtual Private Network). Using it offers several benefits for email security and overall online privacy. When connected to a VPN, all internet traffic, including email communications, is encrypted. Therefore, it is more difficult for hackers or unauthorized entities to access or intercept sensitive information. 

VPN Encryption Explained 600

While VPN can enhance email security, it should be used in conjunction with other email security measures such as end-to-end encryption, secure email clients, and strong authentication methods.

Deploy an Open-Source Email Security Solution

Open-source solutions offer transparency and the flexibility to customize security configurations according to your needs. What is more, collaboration on such products often presumes regular updates, security audits, and improvements driven by a dedicated community.

Besides, an open-source cloud email security solution allows users to inspect the underlying code for security measures. 

Utilize Anti-Spoofing Technology

Spoofing is a threat when an intruder impersonates a legitimate sender. The main goal behind it is to gain unauthorized access to sensitive information. To prevent this problem, Linux users can implement anti-spoofing software or technologies such as Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting, and Conformance (DMARC).

SPF verifies the sender's IP address against a list of authorized ones, ensuring that only legitimate senders can successfully deliver emails. DKIM adds a digital signature to email messages for the recipient to verify the message's authenticity and integrity. DMARC builds upon SPF and DKIM to reduce the risk of domain spoofing. It provides a comprehensive framework to authenticate and monitor email domains.

Ensure client software is patched and up-to-date

Developers constantly release patches and updates to fix security flaws and improve the overall performance and stability of the software. Updating email clients and associated software allows Linux users to take advantage of seamless integration with newer hardware components. 

Frequently installing patches and updating software is also critical. Outdated software may have known vulnerabilities that cybercriminals can exploit. Therefore, Linux users should regularly check for software updates and patches from reputable sources. Enabling automatic updates or setting up regular reminders to manually update email client software ensures that the latest security fixes are implemented promptly. 

To keep track of newly emerged vulnerabilities, Linux users can check security advisories. Here one can find databases that contain issues regarding different software. This information is available publicly and allows businesses to quickly jump into action when a potential threat appears. 

Use Securely Developed Software

When choosing an email security solution, opting for options with safe development practices is essential. Your choice should include software that undergoes regular security audits, follows secure coding guidelines, and has a responsive developer community.

Security software developers often try to reduce the risk of vulnerabilities and ensure that potential security issues are identified and addressed promptly. The choice of their software provides confidence that you use a product that has undergone rigorous security checks. In such a way, you reduce the likelihood of email-based security incidents and protect your sensitive information.

Educate Users

Users are one of the most widespread vulnerabilities in different, even sophisticated, systems. It is necessary to educate users about common email threats in cybersecurity training. One of the best ways to learn about cybersecurity is via these free educational tips and resources. Having learned these pieces of advice will enable the users to identify and respond effectively to suspicious emails.

The training may cover such topics as recognizing phishing attempts, avoiding clicking on suspicious links or downloading attachments from unknown sources, and practicing good password hygiene. Furthermore, users should understand the importance of regular email security assessments, frequent software updates, using strong passwords, and enabling two-factor authentication for email accounts.

Limit Administrator Privileges

The number of users with elevated administrative access should be narrowed to the minimum. Such a restriction reduces the potential damage from email-based security incidents. Also, it decreases the chances of privilege escalation attacks.

Granting administrator privileges only to authorized personnel reduces the risk of undesired access, accidental misconfigurations, or intentional misuse of email systems. Linux users should ensure that individuals have the level of access required to perform their specific tasks only.

Implement Innovative Email Security Technologies

CybersecTo stay ahead of evolving threats, embracing innovative email security technologies is also necessary. These solutions use cutting-edge techniques to detect and mitigate real-time email attacks. Here are some of the examples of open-source tools that are at the forefront of innovation in security technologies:

These tools provide valuable email security benefits such as effective spam detection, malware, and virus protection, content filtering, phishing prevention, and customization options. As open-source solutions with active communities, they offer continuous updates and improvements, ensuring robust protection for organizations against email threats.

In addition to the tools mentioned above, there are other technologies that can enhance email security by other means. An instance of these means is virtual patching, which helps protect against known vulnerabilities by providing temporary fixes until permanent patches are applied. 

Another option is application control. It enables organizations to restrict the execution of unauthorized or potentially malicious software. 

Log inspection allows for the analysis of email server logs, helping to detect and investigate suspicious activities or potential security breaches. 

Some of the advanced security technologies employ Machine Learning (ML) algorithms and behavioral analysis to identify and block malicious emails. Using Machine Learning in security helps prevent phishing attempts, malware infections, and other threats coming from email.

Moreover, ML-based email filtering enhances spam detection accuracy by continuously adapting to new spamming techniques. This technique reduces the risk of users falling victim to fraudulent emails or unsolicited messages.

Defend Against Email Threats with Guardian Digital Open-Source Email Security Solutions

Guardian Digital protects businesses against new and known email threats with its comprehensive EnGarde Cloud Email Security solution. Guardian Digital anticipates the threats specific to your users, and stops them using a collection of flexible filters that adapt to your environment. EnGarde uniquely draws on resources, tools and intelligence available through the vibrant, global open-source community to enhance its protection against all email-borne threats to your business. A product of open-source development, EnGarde is supported by an innovative, collaborative global input program, resulting in rapid updates and superior security and resiliency.

Final Thoughts on Protecting Against Email Threats with Open Source

Email is a vital communication channel for all businesses, but can also present a serious security risk if email security best practices are not implemented. Utilizing reputable open-source technology, as well as implementing the other tips and best practices discussed in this article, is an excellent way to improve the security of your email to defend against cyberattacks and breaches.