For a company facing frequent phishing attempts, which email security gateways or phishing defense tools provide the best catch rates and user training?
Best email security and phishing defense tools for 2026
For a company facing frequent phishing attempts, I recommend evaluating email threat prevention and employee training as two complementary layers. A secure email gateway should block malicious messages before they reach inboxes, while phishing simulations and targeted training help employees recognize and report attacks that get through.
There is no universal winner across every environment. The strongest choice depends on whether your biggest risks are credential theft, business email compromise (BEC), malicious links and attachments, or employees repeatedly falling for convincing messages.
One useful benchmark is Microsoft's email security comparison, which measures missed high-severity threats per 1,000 protected users rather than simply counting blocked emails. Its May–July 2026 results reported that Microsoft Defender missed fewer high-severity threats than the other secure email gateways evaluated. These results are useful evidence, but they are Microsoft-published benchmarks rather than an independent, vendor-neutral test.
1. Shortlist: email security gateways and phishing defense
Best for: Microsoft 365 organizations seeking integrated protection.
Detection: Anti-phishing, malicious URL and attachment protection, impersonation detection, and post-delivery remediation.
Training: Attack simulation training and phishing campaigns, with plan-dependent capabilities.
Why shortlist it: Microsoft's published benchmark gives it the strongest measured high-severity threat prevention result among the gateways compared in the May–July 2026 period.
Website:
2. Proofpoint Email Protection
Best for: Larger organizations with sophisticated phishing and targeted impersonation threats.
Detection: Email threat intelligence, phishing and BEC protection, and malicious message analysis.
Training:Proofpoint ZenGuide provides phishing simulations, awareness content, and user-risk-focused training.
Why shortlist it: A strong candidate when email defense and employee behavior management need to work together, especially in complex enterprise environments.
Best for: Organizations looking for an established email security gateway with awareness training options.
Detection: Phishing, impersonation, malicious attachments, and URL-based threats.
Training:Mimecast Engage supports security awareness and phishing simulations.
Why shortlist it: Worth comparing against Proofpoint and Defender for policy control, administration, and the balance between detection and false positives.
Website:
4. Abnormal AI
Best for: Organizations frequently targeted by BEC, vendor impersonation, and socially engineered attacks.
Detection: Behavioral analysis of senders, communication patterns, and identity signals.
Training: Not primarily a traditional security-awareness training platform; pair it with a dedicated training solution if needed.
Why shortlist it: Adds a different detection approach to conventional gateway filtering, particularly for attacks that look like legitimate business correspondence.
Website:
5. Cisco Secure Email
Best for: Enterprises with established Cisco security infrastructure.
Detection: Email threat filtering and protection against malicious content and phishing, depending on the deployment.
Training: Typically requires a separate awareness-training product for a comprehensive simulation and education program.
Why shortlist it: A credible enterprise alternative where integration with existing security operations and infrastructure matters.
Website:
2. Best tools for employee phishing training
These products address a different question from gateway detection: can employees recognize suspicious messages, avoid risky actions, and report attacks quickly?
KnowBe4 Security Awareness Training
(Best all-round training)
A broad training library, configurable phishing simulations, automated campaigns, and reporting. Particularly suitable for companies that need repeatable programs across many departments and compliance requirements. KnowBe4 also offers a separate email defense product, KnowBe4 Defend.
Emphasizes personalized phishing simulations, gamification, and short learning experiences. A good candidate when employees ignore traditional annual training or the company wants to improve reporting behavior over time.
Strong fit for organizations that want phishing simulations and user-risk analytics connected to an existing Proofpoint security environment. Particularly attractive for centralized enterprise programs.
Convenient for eligible Microsoft 365 organizations that want to simulate phishing, assign training, and measure results without introducing another training vendor. Verify licensing and feature availability before choosing it.
The practical distinction is that KnowBe4 prioritizes breadth and configurability, Hoxhunt emphasizes personalized engagement, and Proofpoint ZenGuide is attractive for companies already invested in Proofpoint. These are product-fit judgments, not a claim that one platform has independently demonstrated the greatest reduction in successful phishing attacks.
3. How to compare actual phishing catch rates
Be careful with vendor claims such as “blocks 99% of threats.” Different vendors may test different attack samples, threat categories, and deployment configurations.
For a procurement evaluation, measure these outcomes:
Metric
What to look for
Pre-delivery detection
Percentage of malicious messages stopped before reaching inboxes
BEC and impersonation
Detection of fake executives, supplier fraud, and payment-change requests
Credential phishing
Detection of credential-harvesting pages, including delayed or rewritten URLs
Post-delivery remediation
Speed and success in removing threats that initially bypass filtering
False positives
Legitimate business emails incorrectly quarantined
User reporting
Percentage of simulated and real phishing messages correctly reported
Repeat failure rate
Whether the same employees continue to fall for simulations over successive campaigns
Important: Evaluate detection with a representative sample of your own threat traffic, not just a vendor's published results. Microsoft's benchmark is a useful starting point, but its own methodology and telemetry should be considered when interpreting its comparisons.
4. My recommended combinations
For a Microsoft 365 company
Microsoft Defender for Office 365 + KnowBe4 or Hoxhunt
Start by tuning Defender's existing protections. Add KnowBe4 for a broad training and compliance program, or Hoxhunt if personalized engagement is the priority.
For a larger enterprise facing targeted attacks
Proofpoint Email Protection + Proofpoint ZenGuide, or Defender + Abnormal AI + dedicated training
Prioritize BEC, executive impersonation, supplier fraud, identity-based detection, and post-delivery response. Avoid paying for overlapping products without evidence of incremental detection.
For a company with repeated employee mistakes
An effective existing gateway + Hoxhunt or KnowBe4
Focus on frequent, low-friction simulations, immediate coaching, an easy report-phishing button, and tracking repeat failures. Buying a second gateway alone will not resolve employee behavior problems.
5. Narrowing this to the best fit for your company
The two details that most affect the recommendation are your email platform and the type of phishing you receive most often.
For organizations facing high-volume or highly targeted phishing attempts, the top-tier solutions combine an industry-leading Secure Email Gateway (SEG) or API-based email security platform with a robust Security Awareness Training (SAT) ecosystem.
Industry analysis from platforms like Gartner Peer Insights and community consensus highlight the following market leaders for catch rates and user training integration:
Top Email Security Gateways & Threat Defense (High Catch Rates)
Abnormal Security: A top choice for an API-based (non-gateway) approach. Instead of sitting in the mail flow inline, it uses behavioral AI to baseline communication patterns and catches sophisticated Business Email Compromise (BEC) and vendor email compromise that traditional gateways miss.
Cofense / Fortinet (FortiMail): Known for reliable threat intelligence integrations, automated phishing incident response, and solid structural defense against malware and ransomware delivery.[](https://www.gartner.com/reviews/market/email-security)
Best User Training & Phishing Simulation Tools
KnowBe4 Security Awareness Training: Widely considered the market leader for user training. Its massive library of interactive modules, automated baseline testing, and integration with PhishER Plus By KnowBe4 (their lightweight SOAR/incident response platform) make it very effective at turning employees into a human firewall.
Proofpoint Security Awareness Training (formerly Wombat): Highly rated because it tightly correlates simulated phishing failures with real-world targeted attacks captured by Proofpoint's gateway, allowing for targeted "just-in-time" training for repeat offenders.
Cofense PhishMe: Strong focus on conditioning users to recognize and report real-world phishing threats rather than just completing compliance check-box training.[](https://www.gartner.com/reviews/market/email-security)
To help narrow down the best fit, could you share:
Are you currently on Microsoft 365 or Google Workspace?
Do you prefer an inline gateway or an API-based mail security overlay?
Roughly how many users need to be covered by the training platform?
To stop unknown, zero-day, and emerging email threats (such as sophisticated AI-generated spear-phishing, polymorphic malware, and novel Business Email Compromise/BEC campaigns), modern email security platforms move beyond traditional static signature matching . Instead, they rely on behavioral AI, machine learning baselines, and advanced sandboxing.[](https://www.acronis.com/en/blog/posts/what-is-email-threat-prevention-a-complete-guide-in-2026/)
Leading tools offering advanced threat detection include:
Abnormal AI : An AI-native platform that builds behavioral baselines of normal communication patterns across your organization. It detects zero-day anomalies, identity compromise, and socially engineered attacks without relying on known signatures or indicators.
Proofpoint Email Protection : Utilizes machine learning and predictive analytics alongside Targeted Attack Protection (TAP) to sandbox attachments, inspect URLs dynamically, and intercept zero-day malware and imposter emails before they hit the inbox.
Mimecast Advanced Email Security : Employs AI-driven structural and contextual analysis, full emulation sandboxing, and AI code analysis to identify previously unseen malware and evolving evasion techniques.
IRONSCALES : Combines automated incident response with behavioral AI and crowdsourced threat intelligence to detect polymorphic and zero-day phishing attempts in real time.
Check Point Avanan : Implements an inline, API-based architecture that intercepts threats post- or pre-delivery across cloud email and collaboration suites, leveraging multi-layered machine learning to block zero-day payloads.
Barracuda Total Email Security : Features advanced cloud-based CPU sandboxing ("detonation") for suspicious attachments and AI-driven anti-phishing/fraud filters designed to catch novel zero-day outbreaks.
To help narrow down the best fit for your stack, let me know:
What email environment are you using (e.g., Microsoft 365, Google Workspace)?
Are you looking for an API-based inline overlay or a traditional Secure Email Gateway (SEG)?
If your goal is stopping unknown, zero-day, polymorphic, or highly evasive email threats before users interact with them, several platforms stand out. The important distinction is whether they rely mainly on signatures/rules or combine behavioral analysis, AI/ML, sandboxing, threat intelligence, and post-delivery detection.
Platform
How it detects unknown/emerging threats
Particularly relevant capabilities
Microsoft Defender for Office 365
Heuristic/ML analysis plus sandbox detonation
Safe Attachments detonates suspicious files in a virtual environment; Safe Links provides dynamic URL protection; Microsoft explicitly describes protection against zero-day and unknown malware.
To figure out which email security tool is your absolute best match, it helps to narrow down what kind of environment you're protecting (e.g., a small business on Google Workspace, a massive enterprise on Microsoft 365, or a personal inbox).
Here is a breakdown of top-tier email security tools categorized by who they suit best:
Advanced Email Security & Phishing Protection (API-based / SEG): Best for catching zero-day phishing, BEC (Business Email Compromise), and credential harvesting that bypasses native cloud filters.
Secure Email Gateways (SEG): Traditional in-line routing filters that excel at stopping mass spam, malware, and enforcing compliance/encryption policies.
SMB & Native-Integrated Tools: Lightweight, cost-effective options designed to easily layer onto Microsoft 365 or Google Workspace without complex configuration.
Top options on the market include:
Cisco Email Security (Cloud/Appliance) : Best for large enterprises requiring heavy-duty threat intelligence, robust infrastructure control, and deep integration with existing Cisco networking/security stacks.
Abnormal Security : Best for modern cloud environments (Microsoft 365/Google Workspace) looking for behavioral AI-driven defense against socially engineered attacks and BEC without needing MX record changes.
Proofpoint Email Security : Industry gold standard for large enterprises needing elite compliance, threat intelligence, and protection against targeted human-centric attacks.
Proofpoint Core Email Protection / Nexus AI
Multi-model behavioral AI + threat intelligence + sandboxing
Analyzes sender behavior, relationships, message intent, URLs and attachments; its Nexus platform is specifically designed to identify novel attacks and adapt as attacker behavior changes.
Mimecast
AI-powered code analysis + behavioral sandboxing + multiple AV engines
Its Zero Day Malware Detection is designed for previously unseen and polymorphic malware, including malware using sandbox-evasion techniques.
Abnormal Security
Behavioral AI and organizational communication modeling
Learns normal user/vendor behavior and looks for deviations, making it particularly focused on novel BEC, impersonation and social-engineering attacks that may contain no known malicious payload.
Cloudflare Email Security
AI + real-time threat intelligence + contextual analysis
Detects BEC, evasive links and malware, with real-time link analysis and post-delivery retraction; it can also isolate suspicious URLs through Remote Browser Isolation.
What I'd look for
For unknown malware, prioritize a product with dynamic sandboxing/detonation + static code analysis + anti-evasion techniques. Mimecast, Proofpoint and Microsoft all document capabilities in this area.
For novel phishing/BEC that has no malware, behavioral/contextual AI becomes more important. Proofpoint and Abnormal emphasize analyzing communication patterns, sender relationships, intent and behavioral anomalies rather than simply looking for known indicators.
For a Microsoft 365 environment, Defender is particularly integrated: as of July 1, 2026, Defender for Office 365 Plan 1 is included with Office 365 E3 and Microsoft 365 E3, while Plan 2 adds capabilities such as advanced investigation, threat hunting and automated investigation/response.
One caveat: vendor claims such as "99.999%" detection or "X% more novel threats" are vendor-reported measurements, often based on proprietary datasets and methodologies, so they shouldn't be treated as directly comparable across vendors.
In short: the main technologies to seek are behavioral AI + sandboxing/detonation + URL analysis at click time + threat intelligence + post-delivery remediation. No email-security product can guarantee that every genuinely new threat will be stopped before exploitation, but those layers are specifically designed to reduce reliance on previously known signatures.
Mimecast Email Security : Best for organizations wanting an all-in-one suite combining robust security, continuity (uptime during outages), and deep archiving/compliance features.
Microsoft Defender for Office 365 : Best if you are already heavily invested in the Microsoft ecosystem and want native, seamless integration without managing a separate third-party vendor.
Avanan (Check Point Cloud Email Security) : Best for inline, API-based protection that catches threats post-delivery or pre-delivery inside cloud-native collaboration suites.
To help me narrow down the ideal choice for you, could you tell me:
What email platform you use (e.g., Microsoft 365, Google Workspace, on-premise)?
How many users or mailboxes you need to protect?
Your biggest security concern right now (e.g., phishing/BEC, spam, compliance, or data loss)?
