For hackers, it's a numbers game. An estimated 3.4 billion phishing emails are sent every day, but all they need is for one of them to find a willing victim and do damage to your network.
And in 2026, the odds have shifted further in the attacker's favor. Generative AI now writes the majority of phishing emails, producing fluent, personalized, typo-free messages that are far harder to spot than the clumsy scams of a few years ago. Research shows AI-crafted phishing lures achieve dramatically higher click rates than traditional ones, while costing attackers almost nothing to produce at scale.
Needless to say, leaving email security up to end users is probably not a good idea.
The Human Element Isn't Going Away
Verizon's 2026 Data Breach Investigations Report (DBIR), which analyzed more than 22,000 confirmed breaches (the largest dataset in the report's history), found that the human element was present in 62% of breaches. That figure hasn't changed much in years, despite billions spent on security awareness programs.
The human element remains the most persistent factor in data breaches.
As threat actors have become more sophisticated in their methods, it's becoming even harder for employees to distinguish between what's legitimate and what's a phishing attempt. The reasons employees fall victim haven't changed much:
- The email looked legitimate. With AI-generated content, malicious messages are increasingly indistinguishable from the real thing.
- The email appeared to come from a well-known brand. (Microsoft alone accounts for roughly half of all brand impersonation attempts.)
- The email appeared to come from a senior company executive, a tactic now strengthened by deepfake audio and video. In one widely reported case, a finance employee wired $25 million after a video call in which every participant, including the “CFO,” was AI-generated.
What has changed is where the attacks land. The 2026 DBIR notes that as users get savvier about email phishing, attackers are switching to mobile-centric social engineering, such as fake text messages (smishing), voice calls (vishing), and QR code lures, with engagement rates roughly 40% higher than traditional email phishing. Attackers are also increasingly impersonating vendors and hijacking existing email threads, which is one reason breaches involving a third party jumped to 48% of the total, a 60% increase year over year.
Attackers are moving to trusted channels: third-party relationships and mobile devices.
Employees are focused on their jobs and trying to get things done quickly. The median time between a phishing email arriving and a user clicking the link is measured in seconds, not minutes. In hybrid work environments full of distractions, it's too easy to see something pop up and make a fast decision without taking the time to verify it.
Training and Education Is Not Enough
While many companies run training and phishing simulations, these programs haven't stopped employees from falling victim. Studies of scenario-based simulations (where employees receive random test phishing emails over time and get coaching when they click) show that many users continue to fall for phishing attempts, sometimes repeatedly.
Training can even backfire when done poorly. Simulations can create a false sense of confidence, leaving employees convinced they can spot a fake, right up until an AI-personalized message written in a trusted colleague's style lands in their inbox. Industry observers reviewing the last several DBIR editions have pointed out that despite fifteen years of simulated phishing and click-rate reporting, too many people continue to fall for these scams.
Research from the Cyentia Institute shows that a small fraction of employees causes most of the incidents: just 4% of users are responsible for 80% of phishing incidents. Training helps, and user reporting improves with good programs, but it will never reduce click rates to zero. And with AI-generated attacks, it only takes one successful message to cause serious damage.
The results show that the best way to defend your organization against email security threats is to prevent them from ever reaching an employee's inbox.
SecurityGateway™ for Email Servers
Secure email gateways help prevent threats from reaching your users. Whether you're hosting your own email server or using cloud email such as Microsoft 365 or Google Workspace, a secure email gateway can protect your business from spam, viruses, malware, ransomware, denial of service attacks, and phishing attempts hidden in email, including the AI-generated variety that increasingly slips past basic filters.
For a quick look at how SecurityGateway protects your email infrastructure, watch this short overview video:
By scanning all incoming and outgoing emails, including attachments, for signs of malicious, harmful, or fraudulent content, email gateways can reject or quarantine potentially dangerous emails. Email gateways check the domains of incoming emails to verify their authenticity and scan the content within the email.
Email security gateways also scan outgoing content to help protect businesses from data leaks or inadvertent release of sensitive information. This is a growing concern as employees increasingly paste company data into unsanctioned AI tools.
SecurityGateway, for example, performs several security tests on emails to block threats from reaching employees. Each test evaluates emails in a variety of ways.
Spam Filtering
SecurityGateway's advanced spam filter scores every email message and allows third-party validation of a sender's trustworthiness. It looks for both known spammers and keywords, phrases, and syntax that are commonly found in spam and phishing emails. In addition to using DNS and URI blocklists, greylisting delays inbound mail from unknown senders. If the email is legitimate, the originating servers will resend the email. Spammers typically just move on to another potential victim.
Anti-Virus
Real-time anti-virus protection checks emails for potential threats. By comparing emails with billions of email messages sampled daily, incoming emails are scanned for patterns that indicate malicious intent. Threat signatures are updated automatically to help detect and mitigate known threats.
Zero-hour virus outbreak protection can proactively protect your email infrastructure automatically when new threat outbreaks are discovered. This is critical now that AI allows attackers to exploit newly discovered vulnerabilities within hours instead of months.
Anti-Spoofing
SecurityGateway also verifies the sender's addresses to uncover forgeries. Before accepting a message, callback verification is used to validate the legitimacy of the sender. Reverse lookups are employed to tag or refuse forged emails. With executive impersonation and vendor impersonation now among the most effective attack vectors, catching forgeries before delivery is more important than ever.
Email Authentication
Additional measures to authenticate email and validate the message sender are also used to minimize spam and forgeries, including:
- DomainKeys Identified Mail (DKIM) uses digital signatures to identify possible tampering.
- Sender Policy Framework (SPF) verifies that email claiming to be from a domain originated from servers that are authorized to send mail for that domain.
- Domain-Based Message Authentication, Reporting and Conformance (DMARC) provides guidance on what to do with messages that fail SPF or DKIM authentication, such as reject or quarantine. It also allows domain administrators to receive reports listing other detected servers that have been used to send mail for their domain. Note that since 2024, major mailbox providers like Google, Yahoo, and Microsoft have required DMARC for bulk senders, making authentication not just a security best practice but a deliverability requirement.
- Relay control to ensure that external domains cannot use your infrastructure to send spam
- IP shielding for email acceptance based on pre-defined domain/IP pairs
- Location screening to block incoming SMTP or remote administration connections from unauthorized countries
- Dynamic Screening and DDoS protection to block suspicious activity
- Tarpitting to deter spammers from abusing your server by slowing down sessions after a specified number of recipients (RCPT commands) have been detected in an incoming connection
Anti-Abuse
Additional anti-abuse features include:
Advanced Filtering
Suspicious emails and other inbound and outbound threats are blocked or quarantined. Content filtering rules with multiple search strings can be defined to search emails for keywords or other content that may indicate threats. These content filters can automatically take actions based on the results, such as rejecting the message, adding points to the message's spam score, or quarantining it for administrative review.
Content filters are also applied to attachments such as video files, images, or executable files to scan for malicious activity. They can even detect Microsoft Office documents containing potentially malicious macros (still a favorite delivery mechanism) and send them to the administrative quarantine for review.
The following video demonstrates how to block attachments containing malicious macros in SecurityGateway:
Allow/Deny Lists
Known email abusers are automatically blocked using address matching, IP blocklists, and host matching. Conversely, authorized senders on your allow list are automatically sent through.
Internal Threat Detection and Prevention
Policy rules, encryption, and automatic secure redirects can help protect sensitive company data from intentional or inadvertent data leaks. Data can be automatically sent over an encrypted connection using Transport Layer Security (TLS), and HTTP requests can be automatically redirected to HTTPS for encrypted access to the SecurityGateway interface. Administrators can set up policies that detect sensitive data and prevent it from being sent outside of your network. Scripts using the Sieve email filtering language can be used to create advanced content filtering rules for industry- or business-specific data.
Protecting Your Network Against Your Biggest Security Threat
A secure email gateway provides significant protection against malicious messages, preventing the overwhelming majority of phishing emails, dangerous links, and attachments from ever reaching your employees' mailboxes, and providing protection against the biggest threat to your network: mistakes by your employees.
The 2026 threat landscape makes this layered approach non-negotiable. Attackers are using AI to industrialize proven tactics such as crafting flawless lures, cloning voices, hijacking vendor relationships, and exploiting the seconds-long window between delivery and click. No amount of training closes that gap. As threat actors deploy increasingly sophisticated, AI-enhanced attacks, a secure email gateway is an essential part of your overall network security strategy.
Learn more about how SecurityGateway for Email Servers from MDaemon Technologies can help secure your business. Download your free trial: https://mdaemon.com/pages/downloads-security-gateway-free-trial
