Introduction

Email remains a primary communication channel for businesses but is also a significant attack vector for cybercriminals. Microsoft 365 and Google Workspace are widely used enterprise email platforms, making them attractive targets for phishing, business email compromise (BEC), ransomware, and data breaches.

As organizations transition to cloud-based email systems, securing email communications and ensuring governance becomes a top priority. Email security solutions now incorporate AI-driven threat detection, real-time email analysis, and compliance automation to protect against modern cyber threats. This blog explores the top 10 email security and governance tools that help enterprises secure their cloud email infrastructure, prevent cyber threats, and comply with regulatory requirements.

What is Email Security & Governance in Microsoft 365 & Google Workspace?

Definition & Importance

Email security refers to implementing tools and strategies that protect an organization’s email system from cyber threats such as phishing, malware, spam, and unauthorized access. On the other hand, email governance ensures that organizations follow regulatory and security policies by enforcing proper email management, archiving, retention, and encryption.

Adequate email security and governance prevent data breaches, financial fraud, legal liabilities, and reputation damage by ensuring the integrity and confidentiality of email communications.

Key Challenges in Cloud Email Security & Governance

1. Targeted Phishing & Business Email Compromise (BEC) Scams

1. Attackers impersonate executives or vendors to trick employees into transferring money or sharing confidential data.

2. Microsoft 365 and Google Workspace users are frequent targets due to widespread adoption.

2. Ransomware & Zero-Day Malware

1. Malicious attachments and links distribute ransomware, encrypting critical business data.

2. Attackers bypass traditional email security solutions using newly created domains and evolving attack techniques.

3. Data Loss & Compliance Risks

1. Sensitive data such as financial records, customer information, and intellectual property may be exposed via unmonitored email traffic.

2. Regulatory non-compliance can lead to hefty fines under GDPR, HIPAA, and ISO 27001.

4. Unauthorized Third-Party Integrations & Risky OAuth Permissions

1. Many third-party apps integrate with Microsoft 365 and Google Workspace, creating potential security gaps.

2. Attackers exploit OAuth permissions to gain unauthorized access to corporate emails.

5. Lack of Visibility & Control Over Email Usage

1. Security teams struggle to monitor inbound and outbound email traffic effectively.

2. Organizations may fail to detect insider threats and policy violations without proper governance.

How AI-Driven Security Tools Help Prevent Cloud Email-Based Threats?

• AI-driven phishing detection: Identifies sophisticated phishing attempts by analyzing sender behavior, email headers, and content anomalies.

• Machine learning-powered spam filtering: Prevents spam emails and malicious attachments from reaching users.

• Automated compliance enforcement: Ensures email retention, encryption, and DLP policy adherence.

• Advanced behavioral analytics: Detects anomalies in email communication, reducing insider threat risks.

Key Features to Look for in Email Security & Governance Tools

1. AI-Powered Phishing & Malware Detection – Uses machine learning models to detect real-time spear-phishing, BEC, and malware attacks.

2. Advanced Spam Filtering & URL Sandboxing – Scans URLs and attachments for zero-day threats and prevents access to malicious websites.

3. Data Loss Prevention (DLP) & Encryption – Protects sensitive emails from unauthorized access and ensures compliance with GDPR, HIPAA, and ISO 27001.

4. BEC Protection – Identifies and blocks email fraud attempts, including impersonation and social engineering attacks.

5. OAuth Risk Management & API Security – Prevents unauthorized third-party applications from accessing sensitive email data.

6. AI-Based Behavioral Analytics & Anomaly Detection – Identifies unusual login locations, unauthorized forwarding rules, and abnormal email activities.

7. Integration with SIEM, SOAR & CASB Solutions – Enables enterprises to centralize email security logs and automate threat response.

Best Practices for Implementing Email Security & Governance

1. Enable AI-Based Email Threat Protection – Prevent phishing and malware attacks before they reach employees.

2. Use Multi-Layered Email Security (DMARC, DKIM, SPF) – Strengthen email authentication and prevent spoofing.

3. Implement Data Loss Prevention (DLP) Policies – Control how sensitive data is shared via email.

4. Monitor OAuth App Permissions & Third-Party Integrations – Reduce risks from unauthorized API access.

5. Automate Compliance Reporting – Use email governance tools to track security events and maintain regulatory compliance.

How to Choose the Right Email Security & Governance Tool?

• AI-Driven Threat Protection – Ensure real-time defense against zero-day email threats.

• Seamless Integration – Choose solutions that integrate Microsoft 365 and Google Workspace security APIs.

• Cloud-Native Security & Compliance Automation – Automate DLP, encryption, and auditing policy enforcement.

• Regulatory Compliance & Audit Logging – Ensure GDPR, HIPAA, and SOC2 adherence.

• Cost & Licensing Model – Evaluate subscription pricing, enterprise licensing, and feature sets.

Best 10 Email Security & Governance Tools for Microsoft 365 & Google Workspace in 2025

1. Microsoft Defender for Office 365

Overview: Microsoft Defender for Office 365 provides robust email protection by leveraging AI-powered threat intelligence to detect phishing, malware, and business email compromise.

Pros:

• Advanced threat protection with AI-based detection.

• Seamless integration with Microsoft 365 security tools.

• Substantial compliance and governance capabilities.

Cons:

• Complex configuration for small IT teams.

• Limited reporting customization options.

User Ratings:

• G2 Rating: 4.5/5 with 289 reviews

• Gartner Rating: 4.5/5 with 194 reviews

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2. Proofpoint Email Protection

Overview: Proofpoint Email Protection is an industry leader in advanced email security, offering superior filtering, URL sandboxing, and AI-driven BEC defense.

Pros:

• Best-in-class threat intelligence and detection.

• Strong URL defense and sandboxing capabilities.

• Effective DLP and compliance controls.

Cons:

• Expensive licensing for large enterprises.

• The steeper learning curve for new administrators.

User Ratings:

• G2 Rating: 4.6/5 with 548 reviews

• Gartner Rating: 4.6/5 with 1182 reviews

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3. Mimecast Secure Email Gateway

Overview: Mimecast offers a multi-layered email security solution with ransomware protection, email continuity, and AI-powered filtering.

Pros:

• Highly effective phishing and malware protection.

• Cloud-based solution with minimal maintenance.

• Easy-to-use interface with customizable policies.

Cons:

• Limited integration with third-party SIEM tools.

• Some users report email delivery delays.

User Ratings:

• G2 Rating: 4.4/5 with 297 reviews

• Gartner Rating: 4.5/5 with 563 reviews

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4. Cisco Secure Email (IronPort)

Overview: Cisco Secure Email provides enterprise-grade protection with email encryption, malware sandboxing, and advanced threat intelligence.

Pros:

• Strong email encryption and compliance tools.

• Effective malware and ransomware sandboxing.

• Seamless integration with the Cisco security ecosystem.

Cons:

• Complex deployment for small IT teams.

• Higher pricing for advanced features.

User Ratings:

• G2 Rating: 4.3/5 with 22 reviews

• Gartner Rating: 4.4/5 with 232 reviews

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5. Barracuda Email Security Gateway

Overview: Barracuda provides cloud-based email security with AI-powered filtering, phishing protection, and policy enforcement.

Pros:

• Effective against phishing and ransomware.

• Intuitive admin interface.

• Strong spam filtering and policy management.

Cons:

• Some false positives in filtering.

• Limited integration with third-party security platforms.

User Ratings:

• G2 Rating: 4.2/5 with 87 reviews

• Gartner Rating: 4.5/5 with 349 reviews

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6.Check Point Avanan Cloud Email Security

Overview: Avanan offers API-based email security that integrates seamlessly with Microsoft 365 and Google Workspace, providing phishing and BEC protection.

Pros:

• API-based deployment requires no MX record changes.

• Strong AI-driven phishing detection.

• Effective BEC protection.

Cons:

• Advanced features require additional licensing.

• Initial setup complexity for non-technical users.

User Ratings:

• G2 Rating: 4.7/5 with 352 reviews

• Gartner Rating: 4.6/5 with 798 reviews

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7. Trend Micro Cloud App Security

Overview: Trend Micro provides advanced AI-powered security for cloud email platforms with automated malware detection and compliance enforcement.

Pros:

• Excellent malware and phishing protection.

• Integration with SIEM and threat intelligence tools.

• Vigorous policy enforcement for compliance.

Cons:

• Can impact email performance in high-traffic environments.

• Complex policy configurations.

User Ratings:

• G2 Rating: 4.3/5 with 44 reviews

• Gartner Rating: 4.7/5 with 216 reviews

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8. Google Workspace Security & Compliance Center

Overview: Google’s native security suite provides built-in email threat protection, compliance enforcement, and automated alerts.

Pros:

• Native integration with Google Workspace.

• Provides visibility into email security events.

• Automates security alerts and compliance reporting.

Cons:

• Lacks some advanced phishing detection features.

• Limited customization options compared to third-party solutions.

User Ratings:

• G2 Rating: 4.6/5 with 42,789 reviews

• Gartner Rating: 4.6/5 with 130 reviews

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9. Virtru Email Encryption & DLP

Overview: Virtru offers end-to-end email encryption and data loss prevention (DLP) to ensure secure email communications and regulatory compliance.

Pros:

• Strong encryption and data protection.

• Easy-to-use for end-users.

• Compliance support for GDPR, HIPAA, and more.

Cons:

• Limited integration with non-Google/Microsoft platforms.

• Additional cost for advanced features.

User Ratings:

• G2 Rating: 4.4/5 with 329 reviews

• Gartner Rating: 4.8/5 with 18 reviews

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10. Tessian Email Security

Overview: Tessian leverages AI to prevent human errors, insider threats, and data exfiltration in email communications.

Pros:

• AI-driven anomaly detection.

• Prevents accidental data leaks.

• Protects against insider threats.

Cons:

• Some AI detections may require manual review.

• Higher pricing for enterprise plans.

User Ratings:

• G2 Rating: 4.6/5 with 44 reviews

• Gartner Rating: 4.8/5 with 13 reviews

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Comparison table: Top 10 Email Security & Governance Tools for Microsoft 365 & Google Workspace in 2025

Frequently Asked Questions (FAQs)

1. What are the best email security tools for Microsoft 365 & Google Workspace in 2025?

The top tools include Microsoft Defender for Office 365, Proofpoint, Mimecast, Cisco Secure Email, and Barracuda Email Security Gateway, offering AI-driven protection against phishing, malware, and compliance risks.

2. How do AI-driven email security solutions prevent phishing & BEC attacks?

AI-driven solutions analyze sender behavior, email headers, and content patterns to detect phishing attempts, impersonation attacks, and malicious links before they reach end-users.

3. Can email security & governance tools prevent insider threats & data leaks?

Solutions like Tessian and Virtru offer behavioral analytics, encryption, and DLP policies to prevent insiders from accidentally or maliciously leaking data.

4. What’s the difference between email security & compliance governance?

Email security focuses on threat protection (phishing, malware, BEC), while compliance governance ensures adherence to regulations (GDPR, HIPAA) through audit logs, encryption, and policy enforcement.

5. Do email security tools integrate with SIEM and other security platforms?

Most advanced email security solutions integrate with SIEM, SOAR, and CASB tools for centralized security monitoring, automated threat response, and enhanced compliance reporting.

6. How can organizations ensure compliance with email security policies?

Organizations can enforce compliance by implementing DLP policies, encryption, email retention rules, and real-time monitoring to meet regulatory requirements like GDPR, ISO 27001, and HIPAA.

7. What’s the cost structure for email security tools?

Pricing varies based on features, deployment models, and licensing. Some tools offer per-user pricing, while others provide enterprise-level subscriptions with advanced security and compliance capabilities.

Conclusion & Call to Action

With increasing cyber threats targeting cloud-based email services, businesses must adopt AI-driven email security solutions. Tools like Microsoft Defender, Proofpoint, and Mimecast provide robust protection against phishing, BEC, and ransomware.

In today’s landscape of increasing cyber threats and regulatory scrutiny, email security and governance are more critical than ever. The right tools provide visibility into risks, enforce compliance, and protect sensitive communications—ensuring organizations stay secure and resilient.

Similarly, CloudNuro brings enterprise-grade governance to SaaS and cloud environments, helping CIOs and CFOs gain deep visibility into software usage, enforce policies, and optimize costs. Just as email security solutions safeguard communication, CloudNuro safeguards your SaaS investments, eliminating waste and reducing financial and compliance risks.

Want to see how CloudNuro can strengthen your IT governance? Book a free demo today.