It’s crucial that organizations using Microsoft 365 find and implement a strong, multi-layered email security solution for their users to tackle advanced threats and enhance security. Microsoft 365 has quickly become one of the most popular cloud-based platforms, making it a prime target for attackers looking for an easy way to compromise email data. In the cloud, email has remained the number one threat vector, with attacks like phishing attacks, spam and ransomware becoming major issues for many businesses.
In this guide, we’ll take you through the top email security solutions for use with Microsoft 365. This article will cover many different kinds of email security technologies that can be used in isolation, or combined with other tools. These solution include Secure Email Gateways, which filter malicious messages before they enter users’ inboxes, Phishing Protection platforms that automatically remove phishing emails, and email encryption solutions that secure email communications.
We’ll cover the key features of these solutions, what makes them perfect to secure emails with Office 365, and what types of customers they are most suitable for.
Abnormal AI is a cloud-native email security platform that leverages behavioral AI to safeguard against various inbound threats, including business email compromise, spear phishing, and malware, as well as internal account takeovers. As a Microsoft Preferred Solution, it integrates seamlessly with Microsoft 365, enhancing security without necessitating changes to MX records or disabling Microsoft’s native security features.
Why We Picked Abnormal AI: We appreciate Abnormal’s use of behavioral AI to establish user communication baselines and analyze emails for over 45,000 indicators of compromise. Its native integration with Microsoft 365 allows for rapid deployment and unified management.
Abnormal AI Best Features: Key features include protection against inbound threats like business email compromise and spear phishing, as well as detection of internal account takeovers. It uses behavioral AI to analyze emails, rewrite URLs in suspicious messages, and insert warning banners. The platform also scans internal communications for malicious activity, automatically logs out compromised accounts, and triggers Microsoft 365 password resets. Integrations include a native API with Microsoft 365.
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Pricing: For detailed pricing, contact Abnormal AI directly.
Who it’s for: Abnormal AI is ideal for organizations using Microsoft 365 who seek robust email security with easy deployment and management. It is particularly beneficial for businesses focused on protecting against sophisticated email threats.
IRONSCALES offers robust protection against phishing, credential theft, and business email compromise for Office 365 users. As a fully cloud-based solution, it operates at the mailbox level to identify and mitigate suspicious email activity.
Why We Picked IRONSCALES: We like its seamless integration with Office 365 and its effective phishing detection and prevention, which outperforms Microsoft Defender for O365 (ATP) according to Expert Insights tests.
IRONSCALES Best Features: Key features include phishing detection and prevention, protection against malicious links and attachments, business email compromise prevention, and security awareness training tools. It uses multiple anti-virus engines and machine learning technologies combined with human threat intelligence to identify and remove malicious emails. IRONSCALES integrates directly with Office 365 via Graph API, requiring no reconfigurations or new mail flow rules, and also offers protection for Microsoft Teams.
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Pricing: For pricing details, visit the IRONSCALES website directly.
Who it’s for: IRONSCALES is ideal for businesses using Office 365 seeking a specialized, easy-to-deploy solution to protect against phishing and business email compromise.
Material Security delivers an automated detection and response toolkit for Microsoft 365, protecting your emails, documents, and accounts. It combines email security, data security, identity protection, and configuration management in a single platform
Why We Picked Material Security: Material provides automated protection for all accounts, users and devices within M365. Material Security’s AI-driven defenses stop phishing, BEC, and malware missed by Microsoft’s filters. The platform also protects sensitive data in files and mailboxes, detects and contains account takeovers, and reduces risk across your environment.
Material Security Best Features: The platform combines AI detection and threat research to block phishing, BEC, and malware, enhanced by user reports and custom keyword rules to swiftly remove malicious emails. Material scans historical emails for sensitive data—like tax documents or invoices—and enforces MFA to protect it during breaches. It also spots password reset links and 2FA codes in real time, adding MFA to prevent account takeovers.
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Pricing: Contact Material Security for details.
Who it’s for: Material Security is ideal for organizations using Microsoft 365 or Google Workspace seeking a comprehensive email security solution that protects against advanced threats and secures sensitive data. It suits businesses of all sizes needing robust email security and governance.
ESET Cloud Office Security is a robust cybersecurity solution designed to enhance the security of Microsoft Office 365 applications. It provides comprehensive protection against spam, malware, ransomware, and targeted attacks like phishing and spear-phishing across Exchange Online, Teams, OneDrive, and SharePoint.
Why We Picked ESET Cloud Office Security: We appreciate its holistic approach to Office 365 security, offering strong anti-malware and virus scanning across all Microsoft applications. Its ability to customize threat protection policies at various levels adds significant value.
ESET Cloud Office Security Best Features: Key features include anti-malware for Exchange Online, Teams, OneDrive, and SharePoint, scanning for malicious URLs and attachments, automatic quarantine or deletion of harmful content, customizable threat protection policies, and detailed reporting and logging. It integrates seamlessly with Office 365 for quick deployment.
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Pricing: For detailed pricing, visit ESET’s website directly.
Who it’s for: ESET Cloud Office Security is ideal for organizations seeking a comprehensive security solution for their Microsoft Office 365 environment, enhancing protection beyond email to include Teams, OneDrive, and SharePoint.
TitanHQ Email Security is a robust email security solution that offers comprehensive protection against advanced threats such as CEO impersonation, phishing, malware, and ransomware. It can be deployed as a cloud-based or on-premise solution, providing effective safeguards for Office 365 email accounts with features like inbound email filtering, data loss protection, and encryption.
Why We Picked TitanHQ Email Security: We like the solution’s multi-layered threat protection and its seamless integration with Office 365, ensuring robust security and ease of deployment.
TitanHQ Email Security Best Features: Key features include multi-layered threat protection, inbound and outbound email security, CEO impersonation protection, phishing and ransomware defenses, link analysis, attachment sandboxing, zero-day attack protection, mail spooling, spoofing protection, SPF/DKIM/DMARC checking, data loss prevention, email encryption, and Office 365 backups. It integrates seamlessly with Office 365.
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Pricing: TitanHQ Email Security is available from $1.08 USD/user/month (based on 250 users).
Who it’s for: TitanHQ Email Security is ideal for SMBs, enterprises, and MSPs seeking a powerful, easy-to-manage email security solution that integrates seamlessly with Office 365.
Check Point Harmony Email & Collaboration (formerly Avanan) is a cloud-native email security solution designed to enhance the protection of Microsoft 365 and other collaboration platforms. It offers a comprehensive suite of tools to defend against phishing, malware, account takeovers, and data loss, integrating seamlessly via API.
Why We Picked Check Point Harmony Email & Collaboration: We value Check Point’s advanced machine learning, which analyzes numerous indicators per email to detect and neutralize sophisticated phishing attacks. Its direct API integration with Microsoft 365 provides a critical layer of enhanced security beyond native defenses.
Check Point Harmony Email & Collaboration Key Features: This solution scans all inbound, outbound, and internal communication traffic to identify and block advanced threats, including zero-day exploits and ransomware. Its features include anti-phishing, malware sandboxing, URL protection, account takeover prevention, data loss prevention (DLP), and encryption. Check Point Harmony Email & Collaboration integrates seamlessly with collaboration suites like Microsoft 365 through direct API connections, offering granular reporting and centralized controls via a cloud-based administration console.
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Pricing: For detailed and tailored pricing information, please contact Check Point directly through their website.
Best Suited For: Check Point Harmony Email & Collaboration is ideally suited for organizations that rely on cloud collaboration platforms like Microsoft 365 and require a robust, multi-layered security solution to effectively protect against advanced and evolving threats while ensuring data security and regulatory compliance.
Cloudflare Email Security is a robust email security solution integrated within Cloudflare’s comprehensive SASE platform. It offers advanced protection against sophisticated email threats, including phishing, email compromise, and credential theft, leveraging Cloudflare’s extensive threat intelligence.
Why We Picked Cloudflare Email Security: We appreciate its seamless integration with Microsoft 365 via API, which simplifies deployment and configuration. Additionally, its end-to-end phishing triage and response capabilities provide comprehensive threat management.
Cloudflare Email Security Best Features: Key features include end-to-end phishing triage and response, insider threat detection, post-delivery email scanning, visibility into compromised accounts and domains, and brand impersonation protection. It integrates with SIEM and SOAR platforms and uses Cloudflare’s Browser Isolation for protection against malicious web links.
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Pricing: For detailed pricing, visit Cloudflare’s website directly.
Who it’s for: Cloudflare Area1 is ideal for businesses already using Cloudflare services, particularly those with Microsoft 365 environments seeking a scalable, cloud-native email security solution.
Microsoft Defender for Office 365 is Microsoft’s security platform designed for enterprise customers using Office 365. It provides robust protection against malicious email threats, including phishing, malicious URLs, and threats within collaboration tools.
Why We Picked Microsoft Defender for Office 365: We like its seamless integration with Office 365, requiring no additional configuration. It also offers comprehensive protection across SharePoint, OneDrive, and Teams.
Microsoft Defender for Office 365 Best Features: Key features include Safe Attachments for scanning email attachments, Safe Links for real-time URL verification, anti-phishing with machine learning and impersonation detection, threat protection policies, and automated investigation and response capabilities in the advanced tier. It integrates directly with Office 365, protecting SharePoint, OneDrive, and Teams.
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Pricing: Microsoft Defender for Office 365 is included in some Office 365 subscriptions like Enterprise E5, or available as an add-on.
Who it’s for: Microsoft Defender for Office 365 is ideal for enterprises already using Office 365 who need a comprehensive, seamlessly integrated security solution.
Mimecast Integrated Cloud Email Security is a robust solution designed specifically for securing Microsoft 365 environments. It integrates seamlessly via an API, scanning emails directly within Microsoft 365 to protect against a variety of sophisticated email threats.
Why We Picked Mimecast Integrated Cloud Email Security: We like its ability to scan emails within Microsoft 365 without MX redirection, and its comprehensive threat detection capabilities that protect against phishing, business email compromise, and credential theft.
Mimecast Integrated Cloud Email Security Best Features: Key features include direct email scanning within Microsoft 365, protection against sophisticated email threats, internal threat detection, and remediation. It also offers mailbox-level compliant archiving, e-discovery, legal hold, Office 365 disaster recovery, email encryption, DNS filtering, and Office 365 migration tools. Integrations include seamless compatibility with Microsoft 365 and support for Mimecast’s Security Awareness Training.
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Pricing: Contact Mimecast directly for detailed pricing information.
Who it’s for: Mimecast Integrated Cloud Email Security is best suited for organizations using Microsoft 365 who need a comprehensive and integrated email security solution that enhances protection and supports compliance requirements.
Proofpoint Core Email Protection is a market-leading email security platform engineered to defend against the complete spectrum of email attacks. Proofpoint’s comprehensive email security portfolio includes a secure email gateway, ML/AI-powered automated remediation, security awareness training, email encryption, and email archiving for any email platform.
Why We Picked Proofpoint Core Email Protection: Proofpoint’s key advantage is the Nexus Threat Intelligence platform, which aggregates and analyzes data from over 3 trillion emails annually. This vast dataset enables robust, crowd-sourced protection against even the most sophisticated and novel email threats. The platform also offers flexible deployment options and advanced features like integrated email DLP.
Proofpoint Core Email Protection Best Features: Key features include real-time, multi-layered detection of phishing and malware, automated investigation and remediation workflows, and highly granular policy configuration. It also provides robust DMARC/DKIM/SPF enforcement and integrated data loss prevention (DLP). The platform supports multipke deployment models: on-premises, cloud-based, Secure Email Gateway (SEG), and API-driven integrations, including seamless integration with Google Workspace via APIs.
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What To Consider:
Pricing: Contact Proofpoint directly for specific pricing details, as costs are determined by organizational size and chosen deployment options.
Best Suited For: Proofpoint Core Email Protection is best suited for enterprises with over 500 users seeking a trusted, enterprise-grade email security and compliance platform. It excels at targeting and mitigating advanced email threats such as spear-phishing and ransomware and currently protects a significant majority (85%) of Fortune 100 organizations.
Proofpoint Essentials is a cloud-based secure email gateway that safeguards small and medium-sized businesses using Office 365 from email threats. It combines email security with archiving, encryption, and data loss prevention to offer comprehensive protection against spam, malware, and phishing attacks.
Why We Picked Proofpoint Essentials: We appreciate its multi-layered email security engines and seamless integration with Office 365, ensuring robust protection without disrupting existing workflows.
Proofpoint Essentials Best Features: Key features include multi-layered email security, URL Defense (SafeLinks), anti-virus engines, email archiving, encryption, and data loss prevention. It also offers advanced BEC defense with Supernova detection, predictive URL defense, and one-click message removal. Integrations include easy deployment with Office 365, allowing for automatic scanning and quarantine of infected emails.
Proofpoint have added deployed inline filtering as a deployment option for M365, so you can either deploy via MX record redirection or inline filtering. The inline filtering option simplyfies the deployment process and can be completed in less than 5 minutes.
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Pricing: For detailed pricing, visit Proofpoint’s website.
Who it’s for: Proofpoint Essentials is best suited for small to medium-sized businesses using Office 365 who need robust, easy-to-deploy email security solutions with advanced threat protection features.
Sublime Security is a programmable cloud security platform for Microsoft 365 that blocks inbound email attacks, hunts for threats, and auto-triages end user reports. It evaluates all email messages using a query language (MQL) and takes actions like quarantining or inserting warning banners based on admin controls.
Why We Picked Sublime Security: Sublime focusses on for its transparent, customizable email filtering rules, avoiding a ‘black box’ approach when it comes to email filtering. We also rate the granular remediation automations and auto-triage that minimize manual email investigation for Microsoft 365 users.
Sublime Security Best Features: Key features include real-time phishing and malware detection, transparent automated remediations, and AI-powered policy automation. The AI-assisted policy builder simplifies rule creation using MQL and GenAI. Proactive AI-powered threat hunting discovers missed attacks, with detailed analytics ensuring transparency and compliance.
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Pricing: A free version is available for single email accounts; contact Sublime Security for enterprise pricing.
Who it’s for: Sublime Defend is ideal for Microsoft 365 enterprises looking for customizable, transparent email security controls with automated remediations and robust protection against phishing, malware, and BEC.
Cloud email security that integrates with Office 365 to prevent sophisticated attacks.
Provides comprehensive security with AI, threat intelligence, and user behavior analysis.
Offers advanced threat protection, spam filtering, and data loss prevention for email.
Uses AI to detect and respond to advanced email threats, including insider threats.
Delivers robust email security with anti-spam, anti-malware, and sandboxing.
Enhances Office 365 security with advanced threat protection and data loss prevention.
Tools / Platforms
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Price
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Link
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Abnormal Security
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$3.00 / User / Month
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IRONSCALES
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Free plan available
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ESET Cloud Office Security
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$121.50 / Year
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TitanHQ Email Security
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$1.95 / User / Month
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Material Security
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$3.00 / User / Month
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Check Point Harmony Email & Collaboration
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Request Quote
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Cloudflare Email Security
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Request Quote
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Microsoft Defender for Office 365
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$2.00 / User / Month
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Mimecast
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Request Quote
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Proofpoint Core Email Protection
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Request Quote
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Proofpoint Essentials
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$1.65 / User / Month
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Sublime Security
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Request Quote
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Selecting the right email security solution for Microsoft 365 in 2025 involves aligning the tool with your organization’s security needs and Microsoft 365 environment. Consider these key steps to make an informed choice:
Assess Your Threat Landscape: Evaluate the primary email threats your organization faces, such as phishing, malware, or Business Email Compromise (BEC), and determine the level of protection needed.
Define Integration Requirements: Factor in your organization’s size, budget, and compliance needs (e.g., GDPR, HIPAA) to ensure seamless integration with Microsoft 365’s cloud infrastructure.
Prioritize Scalability: Choose a solution that supports your current user base and can scale to accommodate growth or increased email traffic.
Focus on critical features to ensure robust protection and seamless operation:
Advanced Threat Detection: Look for AI-driven analysis, real-time URL scanning, and attachment sandboxing to counter sophisticated attacks.
Microsoft 365 Integration: Ensure native integration with Microsoft 365 for streamlined deployment, policy management, and user authentication.
Ease of Management: Opt for intuitive dashboards, automated updates, and detailed reporting to simplify IT administration.
Compliance Support: Verify the solution meets regulatory standards relevant to your industry, such as data protection and archiving.
Balance security with usability to maximize effectiveness:
User-Friendly Design: Avoid solutions with complex setups or frequent false positives that could disrupt productivity or user experience.
Vendor Support Quality: Select providers with responsive support and a proven track record for quick incident resolution.
Testing and Trials: Use demos, free trials, or independent reviews to validate performance and fit before committing.
Our 2025 guide to the top 12+ email security solutions for Microsoft 365 provides a detailed overview of leading platforms, helping organizations enhance protection within their Microsoft 365 environments. The article evaluates solutions based on features like advanced threat detection, seamless Microsoft 365 integration, compliance support, and ease of use, catering to businesses of all sizes. It highlights the importance of balancing robust security with scalability and usability to defend against evolving email threats like phishing and BEC in a cloud-first world.
Key Takeaways:
Enhanced Microsoft 365 Protection: Top solutions offer AI-driven threat detection and native integration to secure Microsoft 365 email environments.
Scalability and Compliance: Choose platforms that scale with your organization and meet regulatory requirements like GDPR and HIPAA.
User-Centric Design: Prioritize intuitive interfaces and reliable vendor support to streamline management and minimize disruptions.
We’ve explored the top email security solutions for Microsoft 365 in 2025, highlighting how these tools safeguard organizations from email-based threats while integrating seamlessly with Microsoft’s cloud platform. Now, we’d love to hear your perspective—what’s your experience with email security solutions? Are features like AI-powered threat detection, Microsoft 365 integration, or compliance tools critical for your organization’s security strategy?
Selecting the right email security solution can transform how you protect your Microsoft 365 environment, but challenges like integration complexity or false positives can arise. Have you found a standout platform that’s strengthened your defenses, or encountered hurdles with usability or scalability? Share your insights to help other organizations navigate the email security landscape and choose the best tool for their needs.
Let us know which solution you recommend to help us improve our list!
Email is a very effective means of reaching to people all over the world who you may or may not know. While this is very useful, it also poses a significant risk to security. You may think that you know who you are in contact with, but how can you be sure? Some of the most common threats to your email inbox include:
Email security solutions will work in several ways to mitigate the threats facing your organization.
Email security tools for Microsoft 365 protect email accounts, content, attachments, and users against malicious activity, compromise, or both accidental or intentional leakage. There are three commonly used approaches to implementing Office 365 email security.
First is by using Microsoft’s own internal protection: Microsoft Defender for Office 365. This is a native email security service which sits on top of the default email security included with Microsoft 365 (Exchange Online Protection). Exchange Online Protection provides advanced threat protection against zero-day malware, phishing, and business email compromises by placing warning banners on email content and automatically removing harmful email messages. This protects external recipients and results in security teams being able to empower users with advanced threat detection and swift incident response.
Second is by deploying a physical or cloud-based secure email gateway. These services monitor all incoming and outbound email traffic to remove spam and malware, using rule-based controls to prevent delivery of harmful email content. This is deployed via redirecting mail exchange (MX records) to point email towards the security service for filtering before deployment.
The third kind of email security method for Microsoft 365 is a category of “integrated cloud email security” (ICES) solutions. These cloud-native email security services deploy via API connection directly into the Microsoft 365 environment, enabling them to scan internal email content in real-time to detect compromised email accounts, phishing-threats, malicious attachments and links.
The best method of Microsoft 365 email security will depend on your specific organizational use cases and risks. SEGs are the best approach to stop malware and harmful email content, while cloud email security services can help to prevent sophisticated phishing threats that may evade the rule based controls of SEG solutions.
Craig MacAlpine is CEO and founder of Expert Insights. Before founding Expert Insights in August 2018, Craig spent 10 years as CEO of EPA cloud, an email security provider acquired by Ziff Davies, formerly J2Global (NASQAQ: ZD) in 2013, which has now been rebranded as VIPRE Email Security. Craig has extensive experience in the email security industry, with 20+ years of experience helping organizations to stay secure with innovative information security and cyber security solutions.