What's the best AI tool to stop phishing and business email compromise?

There is no single "best" tool for every organization, because the ideal choice depends on your current email infrastructure (e.g., Microsoft 365 vs. Google Workspace), budget, and whether you want an API-native overlay or a traditional secure email gateway (SEG).

Instead, the market is led by a few top-tier AI-powered platforms, each specializing in stopping sophisticated phishing and Business Email Compromise (BEC):

• Abnormal AI (Behavioral AI Leader): Best for pure, API-native behavioral anomaly detection. Instead of relying on known threat signatures, it uses AI to baseline normal communication patterns across your entire organization. If a vendor or executive’s display name is spoofed or their writing style changes slightly, Abnormal catches it immediately.
• Proofpoint Email Protection (Enterprise Standard): Best for large enterprises that want deep threat intelligence via NexusAI. Proofpoint is heavily relied upon by the Fortune 100 and handles massive volumes of data, making it exceptionally strong at blocking advanced credential harvesting and spear phishing.
• Check Point Email Security / Avanan (Inline API Protection): Best for blocking attacks before they hit the inbox while maintaining the speed of a cloud-native API deployment. It evaluates internal, external, and lateral emails using advanced machine learning, stopping BEC right at the pre-delivery stage.
• IRONSCALES (Collaborative & Automated): Best for mid-market teams looking for integrated AI and crowdsourced threat response. It combines automated AI detection for BEC and account takeovers with built-in simulated phishing training and automated employee reporting.
• Darktrace / EMAIL (Autonomous Response): Best for catching zero-day and novel AI-generated social engineering attacks. Darktrace’s self-learning AI understands an organization's "pattern of life" to spot subtle nuances in vendor email compromise that static rules miss.

To help narrow down which tool fits your environment best, tell me:

• Are you using Microsoft 365 or Google Workspace?
• Roughly how many mailboxes do you need to protect?
• Do you prefer an API-native solution (no MX record changes) or a Secure Email Gateway?

If your main problem is phishing + business email compromise (BEC) rather than malware generally, my top pick is Abnormal AI.

My ranking

1. Abnormal Security — best dedicated BEC defense

• Particularly strong against CEO fraud, vendor impersonation, payment/invoice fraud, credential phishing, and account takeover.
• Uses behavioral/contextual AI rather than relying primarily on known malicious URLs or signatures.
• Works with Microsoft 365 and Google Workspace and can sit on top of existing email security.
• Best choice if BEC is your #1 concern.

2. Microsoft Defender for Office 365 — best if you're already Microsoft 365

• Very capable and increasingly AI-driven, with anti-phishing, impersonation protection, investigation, automated remediation, and compromised-account detection.
• It can detect coordinated campaigns and anomalous behavior across Microsoft 365.
• Best value if you already have the appropriate Microsoft licensing.
• Important: don't assume the default configuration gives you maximum protection; Microsoft recommends Standard/Strict security policies and appropriate impersonation controls.

3. Darktrace — excellent behavioral detection

• Its email product uses self-learning AI to identify unusual communication patterns and novel threats.
• Particularly interesting for organizations wanting behavioral detection beyond conventional email filtering.

The key distinction

For BEC, I'd prioritize a system that understands:

"Is this email normal for this person, this relationship, this vendor, and this transaction?" rather than simply:

"Does this email contain a known malicious link?" That's why I'd lean Abnormal AI for a company specifically worried about sophisticated BEC.

If you're a Microsoft 365 shop, however, I'd first determine exactly what Defender licensing you already have. Defender already provides spoofing and impersonation protection, and Microsoft specifically addresses BEC as a protected threat category.

My practical recommendation: Microsoft 365 + Defender for Office 365 configured aggressively → start there. High-value targets / frequent BEC / sophisticated social engineering → evaluate Abnormal AI as an additional layer.

If you tell me roughly how many employees you have and whether you're on Microsoft 365 or Google Workspace, I can narrow this down to the best 2–3 options and explain what I'd actually deploy.

And regardless of product, make sure MFA, SPF, DKIM, DMARC, impersonation protection, and external-forwarding controls are configured correctly. Microsoft specifically recommends these controls as part of its anti-phishing posture.

If you tell me (1) Microsoft 365 or Google Workspace, (2) number of employees, and (3) whether you're most worried about phishing, BEC/wire fraud, or account takeover, I can narrow this to the best 2–3 products and what I'd actually buy.

If your main goal is stopping sophisticated phishing and business email compromise (BEC), my top pick in 2026 is Abnormal AI—especially for organizations already using Microsoft 365 or Google Workspace.

My ranking

1. Abnormal AI — best dedicated AI/BEC protection

• Particularly strong against CEO fraud, vendor impersonation, account takeover, payment redirection, and socially engineered attacks that don't contain malware or malicious links.
• Uses behavioral baselines for employees and vendors rather than relying primarily on known bad signatures.
• It can layer on top of Microsoft 365 through an API, so you don't necessarily have to replace your existing mail security.
• My choice if BEC is the specific problem you're trying to solve.

2. Microsoft Defender for Office 365 — best value if you're already Microsoft 365

• Excellent integration with Exchange Online, Entra/identity, Defender XDR, and Microsoft security operations.
• Includes impersonation protection, mailbox intelligence, anti-spoofing, Safe Links/Safe Attachments, investigation, and automated response capabilities.
• Microsoft has also added LLM-based prompt-injection detection in email, which is increasingly relevant as companies deploy AI agents and Copilot.
• My choice if you're already heavily invested in Microsoft 365 and want to minimize another vendor.

3. Proofpoint / Mimecast — strong enterprise alternatives

• Worth considering for large enterprises that want a mature email-security platform, extensive policy controls, and broader security/compliance capabilities.
• I'd put Abnormal ahead of them specifically for a behavioral-AI/BEC-first strategy.

The important distinction

For ordinary phishing, Microsoft Defender can be very good. But BEC is harder because a message can be completely legitimate from the infrastructure perspective: no malware, no malicious URL, valid authentication, and a plausible conversation.

For example:

"Hi, we're changing our bank account for future invoices. Please send the $187,000 payment to the new account." That's precisely where behavioral/contextual analysis becomes particularly valuable. Abnormal explicitly targets these payload-less BEC and vendor-fraud attacks.

What I'd deploy

If you're on Microsoft 365:

Microsoft Defender for Office 365 + Abnormal AI is the combination I'd investigate first.

Defender gives you the native Microsoft security/XDR layer, while Abnormal provides an additional behavioral layer focused heavily on the attacks that can slip through conventional email controls.

If you tell me your company size, Microsoft 365 vs Google Workspace, and whether you're trying to prevent phishing, BEC/payment fraud, or both, I can narrow this down to the best 2–3 options and explain what I'd buy.

There is no single "best" tool for every organization because AI email security platforms approach Business Email Compromise (BEC) and advanced phishing differently—typically splitting into API-native behavioral platforms and enterprise Secure Email Gateways (SEGs).

The top AI-powered platforms on the market excel in distinct categories:

• Abnormal AI (Behavioral AI Leader): Best for pure behavioral anomaly detection. It uses an API-native approach to analyze thousands of behavioral signals and communication patterns. Because it doesn't rely strictly on known malicious signatures or traditional gateway rules, it is exceptionally strong at catching zero-day spear phishing, vendor fraud, and subtle BEC attempts that lack malicious links or attachments.
• Proofpoint Email Protection (Enterprise Incumbent): Best for large enterprises wanting comprehensive, human-centric security. Proofpoint leverages its massive global threat intelligence network alongside advanced machine learning (NexusAI and Advanced BEC Defense) to block impersonation and credential harvesting. It handles compliance and data loss prevention (DLP) exceptionally well.
• Check Point Harmony Email and Collaboration / Avanan (Inline API-Native Protection): Best for intercepting attacks before they hit the inbox via API integration. Avanan pioneered catching lateral/internal phishing and cloud-to-cloud attacks (like compromised internal Microsoft 365 or Google Workspace accounts) that traditional gateways often miss.
• IRONSCALES (Automated Incident Response & Community Defense): Best for mid-market companies and lean security teams. Its AI engine (Themis) assists with real-time detection while heavily automating incident response and crowdsourced threat sharing across its user base to remediate phishing emails quickly.
• Darktrace / EMAIL (Self-Learning AI): Best for autonomous, context-aware defense. Darktrace uses "self-learning" AI to understand a company's unique "pattern of life" in real time, making it effective at spotting novel, highly personalized social engineering and supply chain attacks.

How to Choose:

• Choose Abnormal AI or Check Point (Avanan) if you are on Microsoft 365 or Google Workspace and want modern, API-driven behavioral analysis that bypasses or supplements native cloud filters.
• Choose Proofpoint or Mimecast if you need an enterprise-grade Secure Email Gateway with a deep legacy of compliance, archiving, and robust threat intelligence.

To help narrow down the right choice, tell me:

• What email environment are you using (Microsoft 365, Google Workspace, hybrid)?
• Roughly how many mailboxes do you need to protect?
• Are you looking to replace your current email gateway or add an extra layer on top?

The “best” AI tool for stopping phishing and business email compromise (BEC) depends on your email platform, company size, and whether you need a full email security gateway or an AI layer that catches sophisticated social engineering. Modern BEC attacks often look like normal emails and may not contain malware, so behavioral AI is increasingly important.

Top choices

My practical recommendations

• Small business (Microsoft 365): Start with Microsoft Defender for Office 365 (especially Plan 2 if available), plus MFA and user training.
• 50–5,000 employees where BEC is the main concern: Add Abnormal Security as an AI detection layer.
• Large enterprise, regulated industries, or high-value targets: Evaluate Proofpoint or Mimecast.

Don’t rely on AI email filtering alone

The strongest defenses usually combine:

• MFA resistant to phishing (for example, hardware security keys)
• DMARC enforcement (with SPF/DKIM correctly configured)
• AI email protection
• Payment/vendor verification procedures
• Security awareness training
• Fast reporting and automated mailbox remediation

If you tell me your environment (Microsoft 365, Google Workspace, Exchange, or other), number of users, and budget range, I can narrow this to the best 1–2 options.

There is no single "best" AI tool for stopping phishing and Business Email Compromise (BEC) because the right choice depends heavily on your existing mail infrastructure (e.g., Microsoft 365 vs. Google Workspace), company size, and whether you want an API-native layer or a traditional Secure Email Gateway (SEG).

With attackers heavily utilizing generative AI and automated pipelines to craft hyper-personalized, grammatically flawless spear-phishing and BEC attacks, legacy signature-based filters are no longer enough.

The top-performing AI-powered email security platforms break down by their core strengths:

• Abnormal Security — Best for Behavioral AI and BEC Detection . Abnormal uses an API-native architecture that doesn't require changing MX records. It builds deep behavioral baselines of normal communication patterns for every employee and vendor, allowing it to spot anomalous financial requests, lookalike vendor profiles, and social engineering without generating massive false positives.
• Proofpoint Email Protection — Best for Enterprise Threat Intelligence and Sandboxing . As an established market leader, Proofpoint leverages massive global threat data (processing trillions of emails) alongside advanced machine learning and natural language processing to identify multi-stage malware, credential harvesting, and deeply hidden URL/attachment payloads.
• IRONSCALES — Best for Crowdsourced AI and Automated Remediation . IRONSCALES stands out by combining an adaptive AI layer with a global community of human security analysts (via its Themis virtual SOC). It excels at rapidly removing zero-day phishing emails post-delivery and features built-in phishing simulation and awareness training.
• Check Point Harmony Email (Avanan) — Best for Inline Pre-Delivery Cloud Security . Operating via API directly inside the cloud environment, Avanan intercepts and stops malicious links and BEC attempts before they ever hit the user's inbox, performing exceptionally well across Microsoft 365 and Google Workspace environments.
• Microsoft Defender for Office 365 — Best for Native Integration and Cost-Efficiency . For organizations deeply embedded in Microsoft 365, Defender offers solid, increasingly AI-driven built-in protection (Safe Links and Safe Attachments) that natively coordinates with identity and endpoint logs via Entra ID and Sentinel.

To help narrow down which tool fits best, tell me:

• What email platform do you use (Microsoft 365, Google Workspace, or hybrid)?
• Are you looking for an API-only layer that runs alongside your current setup, or a full gateway replacement?

There is no single "best" AI tool for stopping phishing and Business Email Compromise (BEC), because the right choice depends heavily on your existing email architecture (e.g., Microsoft 365 vs. Google Workspace) and whether you prefer an API-native behavioral layer or a traditional Secure Email Gateway (SEG).

Industry analysis from Gartner's Magic Quadrant for Email Security highlights several leading platforms that excel using AI, natural language processing (NLP), and behavioral baselining to catch sophisticated, code-free social engineering attacks.

• Abnormal Security (Abnormal AI) : Best for API-centric behavioral AI and fast deployment. It connects via API without changing mail flow, building deep relationship and behavioral graphs from historical data. It excels at catching identity fraud, account takeovers, and BEC where there are no malicious links or signatures to flag.
• Proofpoint Email Protection : Best for large-scale enterprise threat intelligence. Recognized as a dominant market leader, Proofpoint utilizes massive global data sets and advanced machine learning (MLX technology) to analyze hundreds of thousands of attributes per email, alongside specialized tracking for "Very Attacked People" (VAPs).
• Check Point Email Security (Avanan) : Best for inline API-based pre-delivery protection and tool consolidation. It scans hundreds of phishing indicators and secures collaboration apps (like Slack and Microsoft Teams) alongside email, stopping zero-day threats before they hit the inbox.
• Darktrace / EMAIL : Best for autonomous, self-learning anomaly detection. Rather than relying solely on known attack patterns, Darktrace uses self-learning AI to understand normal user communication rhythms and can autonomously quarantine anomalous or compromised account behavior.
• Microsoft Defender for Office 365 : Best for M365-native organizations. For companies deeply embedded in the Microsoft ecosystem, its native LLM-based intent analysis and integration with broader XDR/Sentinel signals provide robust, frictionless protection.

To help narrow down the ideal choice for your organization, let me know:

• What email provider do you currently use (Microsoft 365, Google Workspace, or hybrid)?
• Are you looking to replace your current gateway or add an API-layer on top of it?
• What is your approximate mailbox count?

For phishing and business email compromise (BEC), the “best” AI tool depends on your environment, but the strongest options today are generally:

My short recommendation

• Small/midsize company on Microsoft 365: Start with Microsoft Defender for Office 365, then add Abnormal Security if BEC is a major concern.
• Company that frequently receives wire-transfer requests, invoices, or vendor emails: Abnormal is often the strongest specialist choice because it focuses on behavioral signals rather than only known bad links/files.
• Large enterprise with compliance/SOC requirements: Proofpoint is usually the safer all-around platform.

A strong deployment usually combines:

1. AI email detection (Abnormal, Proofpoint, Microsoft Defender, etc.)
2. MFA resistant to phishing (for example FIDO2/security keys)
3. DMARC enforcement to prevent domain spoofing
4. Payment-change verification procedures (because many BEC attacks contain no malware—just a convincing request)

If you tell me your size (e.g., 10 employees vs 10,000), email platform (Microsoft 365 or Google Workspace), and whether you already have an email gateway, I can narrow it to a specific recommendation.

There is no single "best" AI tool for every organization, because the ideal choice depends on your infrastructure (e.g., Microsoft 365 vs. Google Workspace), your deployment preference (API-native vs. Secure Email Gateway), and whether you need an all-in-one suite or a specialized overlay.

Leading enterprise platforms rely on behavioral AI, Natural Language Processing (NLP), and communication graph analytics to stop zero-payload Business Email Compromise (BEC) and sophisticated phishing. Top industry options are categorized below by their primary strengths:

• Abnormal AI (formerly Abnormal Security): Best for Behavioral AI and Rapid API Deployment . It integrates via API in minutes without changing MX records. It maps organizational relationship graphs and builds strict behavioral baselines for every employee and vendor, making it exceptionally strong at catching subtle BEC and invoice fraud that lack malicious links or attachments.
• Proofpoint Email Protection : Best for Enterprise Scale and Threat Intelligence . As a dominant market incumbent with massive global threat visibility, Proofpoint combines advanced machine learning, NLP, and deep threat graph analytics. It is ideal for large enterprises needing multi-layered defense and robust URL/attachment isolation.
• Check Point Email Security (Avanan) : Best for Consolidated Workspace Protection . An inline, API-native solution that catches threats missed by default cloud email controls. It extends AI-driven inspection past the inbox to secure collaboration tools like Microsoft Teams, Slack, and OneDrive.
• IRONSCALES : Best for Crowdsourced AI and Automated Incident Response . It combines an adaptive AI layer with a human-element feedback loop (a global community of analysts) and a virtual security analyst ("Themis") to drastically cut down forensic investigation and remediation times.
• Darktrace / EMAIL : Best for Self-Learning Anomaly Detection . Part of Darktrace's broader active AI platform, it uses custom, self-learning AI models that understand "self" for your specific network and email environment rather than relying solely on pre-trained global threat feeds.

To help narrow down the ideal choice for your environment, tell me:

• What email platform do you use (Microsoft 365, Google Workspace, hybrid)?
• Are you looking for an API-native overlay or a traditional Secure Email Gateway (SEG)?
• Do you also need phishing simulation and training bundled in?

If your main goal is stopping phishing + business email compromise (BEC), my top pick in 2026 is Abnormal AI—especially if you're on Microsoft 365 or Google Workspace.

My ranking

Why Abnormal gets my nod for BEC: BEC frequently has no malicious attachment or URL. It's essentially an attacker saying, "I'm your CEO/vendor—please change this bank account," which makes conventional signature/scanning defenses less effective. Abnormal's behavioral AI analyzes identity, relationships, communication patterns, and message intent rather than simply looking for known malicious indicators.

But there's an important distinction

If you already have Microsoft 365, don't automatically replace Defender. Microsoft has substantially capable anti-phishing, spoofing, and impersonation protection, including enhanced impersonation controls in Defender for Office 365.

A very strong architecture is:

Microsoft 365 + Defender → Abnormal AI → identity/MFA controls → payment verification

For a larger organization, Proofpoint is arguably the stronger choice if you want a comprehensive email-security platform rather than primarily an AI BEC layer. Its current platform combines AI, behavioral analysis, threat intelligence, URL/attachment protection, account-takeover defenses, and BEC protection.

And Mimecast deserves a serious evaluation too: its current BEC protection combines NLP, social graphing, relationship verification, and behavioral analysis, and it extends protection into Teams and Slack.

If you tell me your company size (e.g. 50, 500, 5,000 employees) and whether you use Microsoft 365 or Google Workspace, I can narrow this to the best 2–3 options and explain which I'd actually buy.