Mimecast vs Abnormal

Mimecast and Abnormal differ across both deployment and detection.

Deployment

Mimecast offers MX-based and API-based deployment options. API-based setup goes live in minutes for rapid proof of value, while MX-based adds pre-delivery prevention, outbound/internal scanning, and mail-routing control. Abnormal provides API-only deployment with post-delivery remediation only.

Detection

Abnormal uses AI-driven behavioral detection that combines NLP, social graphing, behavioral analytics, and threat intelligence to establish baselines and spot anomalies. It performs basic file-type validation on attachments and reputation-based URL checks, but no deep scanning or detonation of URLs or attachments occurs at any point.

Mimecast provides all of the above, plus:

• Full-emulation sandboxing with anti-evasion AI and multi-engine AV
• AI-based code analysis
• Deep URL detonation with computer vision, browser isolation, QR-code scanning, and multi-hop redirect following
• Click-time deep scanning of destination content
• Broader customer exposure to threat signals (~70B messages/month across 42,000+ customers)
• HRM-driven adaptive policies that strengthen controls automatically

Mimecast’s larger, more diverse telemetry pool (~70B messages/month across 42,000+ customers vs Abnormal’s ~3,000 customers) provides richer insight into emerging campaigns, bad infrastructure, and attack patterns.

Mimecast provides deep, multi-layer protection for payload-based threats, utilizing full-emulation sandboxing with anti-evasion AI, multi-engine AV, AI-based code analysis, and static + dynamic file analysis. These engines operate independently of Microsoft.

Abnormal performs basic file-type validation — checking whether attachment types are normal for the sender-recipient relationship — but has no sandboxing, no multi-engine AV, and no AI-based code analysis for inbound email. It relies primarily on behavioral context and Microsoft Defender for deep payload-based threats. A well-crafted email from a compromised legitimate account, carrying a weaponized attachment of a normal file type, would pass both Microsoft and Abnormal's behavioral checks. Only deep, independent payload inspection catches this scenario.

Abnormal does not provide independent malware or ransomware protection for inbound email. It performs basic checks but has no full-emulation sandboxing, no multi-engine antivirus, and no AI-based code analysis. Its approach assumes Microsoft Defender will handle deep payload-based threats while Abnormal adds a behavioral and contextual layer on top. This creates a critical dependency: if Microsoft misses a threat and the attachment type appears normal for the relationship, Abnormal has no independent payload inspection to catch it. Mimecast provides a fully independent malware detection stack that operates regardless of Microsoft's effectiveness.

No. Abnormal is API-only and operates entirely post-delivery. All threats are delivered to the inbox first, then remediated (moved/deleted) after the fact. During the time between delivery and remediation — which can range from seconds to hours depending on Graph API performance and Abnormal platform availability — users can see, open, click, and interact with malicious content. Mimecast's MX-based deployment blocks threats before they reach the inbox, eliminating user exposure entirely.

Mimecast's Human Risk Management platform centralizes risk insights from email security telemetry, security awareness training and phishing simulations, data handling events, and 17 integrated security tools across six security domains — email, collaboration, identity, endpoint, cloud security, and user behavior — including CrowdStrike, Okta, and Netskope. HRM drives adaptive policy controls that dynamically adjust email security based on each user's risk score, behavioral nudges (via email, Slack, and Teams), individualized user scorecards, and closed-loop governance connecting behavior → risk → policy enforcement.

Abnormal has no HRM platform. It provides AI-driven phishing simulations and limited awareness training content, but does not offer unified risk scoring across multiple security domains, adaptive policy enforcement, behavioral nudges, user scorecards, or closed-loop risk governance.

Mimecast provides comprehensive DLP, misdirected email protection, and Insider Risk Management capabilities. Misdirected Email Protection (MEP) uses social graphing to detect and prevent emails sent to unintended recipients. Email Content Examination DLP applies policy-driven controls with blocking capabilities across outbound email. Incydr delivers full Insider Risk Management with visibility and blocking across endpoints, cloud apps, email, and web. Automated response actions include blocking file uploads, blocking browser activity, isolating devices, enforcing preventative browser extension controls, and issuing real-time user nudges. Mimecast meets and exceeds Gartner's Market Guide for Insider Risk Management Critical Capabilities.

Abnormal offers misdirected email prevention using anomaly detection, social graphing, and NLP to flag unusual sending patterns and recipient mismatches. However, it has no email DLP, no endpoint data movement monitoring, no file-based DLP, no risk scoring across users, files, and destinations, and no response controls for containing or blocking data exfiltration. Its approach to insider risk is fundamentally limited to the email channel.

Mimecast DMARC Analyzer provides advanced, dedicated tooling to protect an organization's domains from being spoofed. It helps organizations correctly publish and manage SPF, DKIM, and DMARC records, authenticate outbound email, and safely move toward a full enforcement (reject) policy. A key advantage is DNS hosting capability, which overcomes SPF's 10-lookup limit. DMARC Analyzer provides structured guidance, reporting, and alignment visibility, ensuring outbound authentication compliance with Microsoft and Google requirements, increasing deliverability, and preventing attackers from sending fraudulent messages using your brand.

Abnormal does not offer DMARC management or DNS hosting services.

Both platforms provide API-based, post-delivery scanning for collaboration tools, but they differ significantly in detection depth, platform coverage, and governance.

Platform coverage: Mimecast Collaboration Security protects Teams, SharePoint, and OneDrive — covering the full Microsoft 365 collaboration ecosystem including file storage. Abnormal's Messaging Security covers Teams, Slack, and Zoom but does not protect SharePoint or OneDrive.

Detection depth: Mimecast extends its full URL detonation, file sandboxing, and malware analysis engines into collaboration tools. Abnormal can sandbox suspicious attachments and remediate flagged messages in supported platforms, but link scanning remains reputation-only — no deep URL detonation, computer vision, or redirect chain following. This means zero-day phishing pages with no reputation history can pass through undetected.

Governance and archiving: Mimecast provides Cloud Archive for collaboration content archiving and eDiscovery, AI-driven supervision for regulated industries, and Signal & Spotlight for collaboration governance across Teams, Slack, and Zoom — including behavioral insights, sentiment analysis, toxic speech detection, and NLP-driven investigations. Abnormal provides no archiving, eDiscovery, supervision, or governance for collaboration content.

No. Abnormal does not have a brand protection product. It does not monitor for lookalike domains, fraudulent websites, or brand impersonation across external channels, and does not offer takedown services. Mimecast Brand Exploit Protect proactively monitors for lookalike domains and phishing sites across email, web, and social, with active takedown services to remove fraudulent domains and websites before they reach customers or partners.

Mimecast provides a complete compliance and governance stack that Abnormal does not offer, including:

• Cloud Archive with immutable storage, retention management, legal hold, and tamper-proof audit trails across email and collaboration
• eDiscovery and Supervision for regulated industries with review workflows and monitoring tools
• Search & Discover with cross-platform search, AI-based sentiment analysis, toxic speech detection, and multilingual NLP
• Signal & Spotlight for collaboration governance across Teams, Slack, and Zoom with behavioral insights and NLP-driven investigations

Mimecast is a Leader in the 2025 Gartner® MQ for Digital Communications Governance & Archive. Abnormal provides no archiving, eDiscovery, supervision, retention, legal hold, or compliance tooling of any kind.

Mimecast provides essential services Abnormal does not, including:

• Email Routing and Continuity to keep mail flowing during outages (100% availability SLA)
• Archiving, eDiscovery, and Supervision for compliance (Leader in 2025 Gartner® MQ for DCGA)
• Robust DLP and Insider Risk Management across endpoints, email, cloud, and web (meets and exceeds Gartner's IRM Critical Capabilities)
• DNS Checks and DMARC management for domain protection
• Brand Exploit Protection with active takedown services
• Sync & Recover for independent email backup and disaster recovery

Mimecast includes internal (east-west) email protection in all packages and deployment methods by scanning internal email attachments with full sandboxing and URLs with deep analysis. This protects against compromised accounts and malicious insiders. Abnormal only enables internal email scanning when the Account Takeover add-on product is purchased, and even then provides only behavioral/contextual checks with no deep payload inspection.

Abnormal depends on Microsoft Graph API to remediate threats post-delivery. If Abnormal's platform or the Graph API experiences an outage, malicious emails remain visible and clickable in inboxes until service is restored. Abnormal's own status page documents recurring platform maintenance windows and incidents. Mimecast's MX-based deployment blocks threats before delivery, independent of Graph API availability, backed by a 100% email availability SLA with built-in continuity.