Email security remains one of the top priorities of businesses of all sizes in 2025. Sophisticated attacks via email, such as phishing, ransomware, or malware, remain a constant threat. At the same time, business email compromises (BCE) and other dangerous attacks that do not rely on malware become more complex thanks to the rise of artificial intelligence (AI).
Email demands a better security to counterweight to the ever evolving threat landscape on the inbox.
Mimecast Advanced Email Security is a well-established cloud-based solution for mid-sized and large organizations. Our in-depth analysis of the email protection service will give you a clear view of its features, including those that may be missing or lacking, and how it stacks up against the competition.
How does Mimecast Email Security work?
Mimecast maintains two email security products. Cloud Integrated, which is a full cloud-based solution that integrates only with the Microsoft 365 platform, and Cloud Gateway, which expands security to Google Workspace, hybrid, and on-premises platforms.
Both Mimecast email security products offer protection against the top attack vectors that can reach your email, such as phishing, quishing, malware, impersonation, social engineering and payment fraud. AI is used to detect the most dangerous attacks before they reach the customer’s inbox and to handle threats retroactively.
Mimecast calls its core product Secure Email Gateway. It is a 100 percent cloud-based solution that integrates with Microsoft 365 and Google Workspace, offering the strongest possible protection to defend your business. Emails pass through the Mimecast servers before they reach the inbox of the individual user or organization.
Hybrid and on-premises solutions are also available, which is especially important in highly regulated industries such as healthcare or finance.
Mimecast Email Security Features
Advanced AI Powered detection with machine learning
Mimecast uses artificial intelligence and machine learning to analyze more than 1.7 billion emails and 7 billion signals in emails daily. The large amounts of data enable Mimecast to identify patterns and block threats proactively.
Anything email related, including incoming and outgoing emails, is analyzed by the service to detect threats and run countermeasures.
Protections include:
- Phishing protection (including spear phishing).
- Quishing (QR-Code phishing) protection.
- Social engineering.
- Spam.
- Denial of service attacks.
- URL scanning.
- File scanning.
- Zero-day threat detections.
Email security, impersonation and spoofing defenses
Mimecast Advanced Email Protection supports several industry standard email authentication protocols to identify and prevent spoofing. The main ones are:
- Sender Policy Framework (SPF) checks if the sending server’s IP address is authorized to send emails for the domain.
- DomainKeys Identified Mail (DKIM) attaches cryptographic keys to emails, which the receiving server checks to verify its authenticity.
- Domain-based Message Authentication, Reporting and Conformance (DMARC) defines rules for emails that fail SPF or DKIM checks.
Data leak prevention
In addition to scanning incoming emails, Mimecast is also scanning internal emails and outbound emails to prevent leaks of sensitive data. The system supports several methods of detection, including keyword matching, file hashing, or pattern recognition.
Secure messaging support
Mimecast users may send encrypted emails directly from Outlook using tighter controls and permissions. Supported are, among other options, the setting of expiration dates, read receipts, or restrictions on printing of forwarding.
Administrators may configure policies to encrypt certain emails automatically to reduce user error.
Protection of collaboration tools
Security is extended to widely used Microsoft collaboration tools, like Microsoft Teams or SharePoint. Mimecast scans files, chats, and links to detect malware, phishing attacks, policy violations, or other types of threats and issues.
Post-delivery threat remediation
Mimecast email security with threat protection is an integrated feature. When threats are detected retroactively, e.g., when an URL is turned into a phishing resource or malware is detected in a file that passed detection previously, threat remediation may kick in to prevent harm and isolate the issue.
The feature may notify administrators about the newly found threat or act independently to remove the threat automatically.
Security Features and Compliance
Mimecast complies with major industry standards regarding security and compliance. The company divides certification and attestation into the groups “Access Control”, “Privacy”, and “Resilience”.
- ISO-27001
- ISO-27701
- SOC2 Type II
- ISO-22301
- ISO/IEC 42001:2023
- HIPAA
- TISAX
- IRAP
- CSA
- GDPR
Mimecast achieved the FedRAMP ATO “ready” status back in 2020, a precursor to becoming fully authorized within the Federal Risk and Authorization Management Program (FedRAMP). There is no indication, however, that it received full FedRAMP ATO up to this date.
Customer Support and Help
Customers may also use self-service options via the Mimecast Central community, where they may access a knowledge base and interact with other customers directly.
Extensive developer documentation, for instance on API email security, is also available.
Mimecast email security training is offered through the Mimecast University and Mimecast Education program. Videos are available for users and technical administrators and may include live instructor-led courses.
Users may also sign-up for security training courses designed to raise security awareness. These are module-based and focus on specific topics, such as phishing training or Insider threat awareness training.
Mimecast Email Security Pricing
Recent user reports suggest that the price ranges typically between $3 and $12 for each user and month for medium-sized businesses. The price depends on several factors, including the number of licenses and add-on services.
Discounts are reportedly possible, especially for multi-year contracts and larger subscriptions.
While there is no trial, Mimecast does offer a 30-day free scan option for Microsoft 365. While limited to Microsoft 365, it is deployed rapidly, does not impact email communications, and is ideal for testing the product before making a commitment.
Pros and Cons
Here is a summary of the advantages and disadvantages of Mimecast Email Threat Protection based on our analysis and this review.
Pros
- AI powered protection against all kinds of email threats (proactively, retroactively and against 0-day attacks)
- Protection extends to messaging and some collaboration tools.
- Cloud Gateway plan supports on-premises and hybrid solutions.
- Integrated in Mimecast’s Human Risk Management Platform
- Wide range of training and support options.
- Wide compliance and security standards support.
- Strong reporting and analytics capabilities.
- Free training provided to users.
- Comprehensive documentation.
Cons
- The website offers no price information. Third-party reports suggest that the cost per user and month is relatively high compared to the competition.
- Some features may require additional licenses.
- Steep learning curve on the technical side for mastering features.
- Reports suggest that customer responses may be delayed at times, especially during peak business hours.
- Advanced setups may be complex to set up.
What we like about Mimecast Email Security
Mimecast is a robust email security platform that uses a multi-layered approach to bring enterprise grade protection to your business. It integrates well within Microsoft’s ecosystem of services and tools but may also be extended to Google Workspaces and other solutions using the Cloud Gateway plan.
Use of AI systems push analysis and detection of threats, with the service claiming that it blocks 99% of all spam with a 0.0001% false positive rate. Malware protection is extended to collaboration tools as well as internal and outgoing emails.
Protection is extended to collaboration tools, which benefit organizations that make heavy use of Microsoft Teams, SharePoint, or OneDrive.
The unified dashboard is intuitive. Administrators may use it to manage policies, quarantined items and to access reports. Reporting and analytics provide real-time insights into emerging threats and trends, traffic, or user activity.
Mimecast maintains additional security solutions to address additional threats. Mimecast Inc Ydr, for example, aims to prevent data loss and leaks using AI. Another service, Mimecast Aware, collects, processes, and preserves collaboration data at scale in a single location for better manageability.
What could be better
Mimecast Email Security Alternatives
How does Mimecast stack up against three of its main competitors?
Proofpoint vs Mimecast
Is a leader in email security. Its core product, NexusAI, uses machine learning and AI to block common and advanced email threats. Proofpoint offers similar core functionality but has a stronger focus on protecting high-risk users through its Very Attacked People feature. Proofpoint calls itself the “leader in human-centric security” to protect against human-targeted threats, which sits at the core of its business.
Avnan vs Mimecast
Avnan, which is called CheckPoint Email Security since its acquisition in 2021, is a cloud-based email protection solution for Microsoft 365 and Google Workspace environments. The service connects via API to add a security layer to the used products without interfering with native existing filters.
Symantec Email Security vs Mimecast
Acquired by Broadcom in 2019, Symantec’s email security feature integrates well with Broadcom’s ecosystem. The cloud-based service supports major cloud-platforms, including Google Workspace and Office 365, and on-premises solutions such as Microsoft Exchange as well. Reports suggest that innovation has slowed post-acquisition though, which could limit adoption of new technologies.
Final Thoughts
Standout features are Mimecast’s advanced threat protection feature handling incoming, outgoing and internal emails alike. Setup is straightforward, at least when it comes to integration with Microsoft 365 or Google Workspaces.
On the downside, Mimecast’s reliance on third-party threat detection is a double-edged sword that may lead to detection and remediation delays.