Email remains one of the most common attack vectors, and business email compromise alone accounted for $3.05 billion in losses in 2025, according to the FBI's Internet Crime Complaint Center (IC3).¹ Sublime Security's agentic, detection-as-code approach appeals to security teams wanting a rules-first approach, but can require dedicated engineering resources that not every organization has available. Whether you need more time back, broader threat coverage, or a behavioral approach, these Sublime Security alternatives offer distinct approaches to stopping email-borne threats before they reach users.
Sublime Security at a Glance
Sublime Security serves organizations who favor a rules-first approach for email security.² The platform provides detection-as-code email protection through automatic rule creation or manual detection tweaks, all written in Message Query Language (MQL).³ This is a domain-specific language designed for email security that enables defenders to write, run, and share detection rules across email providers.⁴
Key characteristics include:
Community-Driven Development: Open-source repository where security teams contribute and refine detection logic.⁵
Engineering-Heavy Approach: Custom protection typically requires dedicated detection engineering resources.⁶
Continuous Rule Creation: Agents or Sublime admins can create detections for threats identified as malicious.⁷
Why Organizations Look for Sublime Security Alternatives
Organizations may evaluate alternatives when detection management resources, platform coverage needs, or novel threat requirements don't align with Sublime's approach.
Limited Detection Management Resources
Not every security team can dedicate staff to maintaining custom detection rules. Organizations without detection engineers need solutions that work without requiring custom rule maintenance. The operational burden can extend beyond initial implementation. Maintaining a detection-as-code system typically requires either dedicated engineering time or dependence on community and vendor updates if the organization wants protection against new email threats.
Broader Platform Coverage Needs
Some organizations need protection beyond email. Account takeover, SaaS security, collaboration tool protection, and security awareness and training represent critical security gaps that some organizations want unified platforms to address through integrated threat correlation.
Novel Threat Protection
GenAI tools have made it easier than ever for attackers to create new variants that bypass detections. If users want protection that extends beyond advanced email attacks, they may want a behavioral approach that understands identity, context, and risk across the organization in addition to known threat signatures.
Top Sublime Security Alternatives
These eight alternatives represent different approaches to email security, from behavioral AI to gateway protection to hybrid models.
1. Abnormal
Abnormal uses behavioral AI to detect business email compromise, vendor email compromise, AI-generated phishing, and account takeover by analyzing organization-wide communication patterns, message context, and environmental risk signals. The platform is designed to analyze communication patterns to help identify subtle anomalies indicating sophisticated attacks, including payloadless threats, socially-engineered attacks, and novel attacks. It's designed to operate without rule-writing or manual tuning, but customer-created Custom Rules and Custom AI Models are available.
Industry Recognition:
Leader in the 2025 Gartner® Magic Quadrant™ for Email Security for the second consecutive year, placed furthest on the Completeness of Vision axis⁸
Named a Customers' Choice in the 2026 Gartner® Peer Insights™ Voice of the Customer for Email Security,⁹ the only email security vendor to earn the distinction for the third consecutive time as of September 2026, with 98% of surveyed customers saying they would recommend Abnormal as of June 2026
4.8/5 overall experience rating based on 182 verified reviews on Gartner® Peer Insights™ as of June 2026¹⁰
Forbes® Cloud 100™ (2025)¹¹ and CNBC® Disruptor 50™ (2026)¹² recognition
Trusted by more than 5,000 organizations, including 30% of the Fortune® 500 as of September 2026¹³
Core Capabilities:
Inbound Email Security: Detects targeted business email compromise (BEC), vendor email compromise, and phishing by analyzing a broad set of behavioral signals across identity, communication pattern, and content, then automatically remediates malicious emails based on customer-defined risk tolerance.
Misdirected Email Prevention (Limited GA on Microsoft 365):¹⁴ Uses behavioral AI to catch outbound emails headed to the wrong recipient, such as a similarly named colleague or a mistyped domain, before they leave the organization, helping address an outbound data-loss gap legacy tools were not typically designed to cover.
Posture Management: Continuously benchmarks Microsoft 365 configurations against Center for Internet Security (CIS) standards, flagging misconfigurations like risky multi-factor authentication (MFA) settings or forwarding rules so security teams can address them.
AI Phishing Coach:¹⁵ Turns the real attacks Abnormal stops into phishing simulations and just-in-time coaching, replacing generic security-awareness content with training based on the specific attack patterns and simulations employees have encountered.
AI Security Mailbox: Triages and responds to user-reported phishing emails automatically, reducing the manual review load on the SOC.
AI Data Analyst: An inbox-native AI agent that answers security questions in natural language and builds executive-ready reports without dashboards or queries.
Email Productivity: Sorts promotional and low-priority mail according to each user's preferences to clear graymail without added policy work.
Behavioral Detection: Establishes communication baseline across identities and environments, correlating identity, behavior, and content signals together, then flags deviations from normal communication patterns that can indicate impersonation or compromise.
Because this approach checks whether communication patterns match established norms rather than relying solely on known threat indicators, it can catch business email compromise and social engineering attacks that lack traditional signals like malicious links or attachments, including novel and AI-generated phishing that can evade signature-based tools. Understanding normal behavior can also mean fewer legitimate emails get flagged by mistake, while automating detection and remediation can free analysts for other work.
Best For: Enterprise prioritizing autonomous email protection and SOC efficiency. Learn more about Abnormal's approach.
2. Proofpoint
Proofpoint provides email security through Proofpoint Nexus, an ensemble of AI models that classifies business email compromise, phishing, malware, and spam threats.¹⁶ Advanced BEC Defense detects display-name spoofing, lookalike domains, and supplier fraud.¹⁷
The platform integrates with Microsoft 365 via API¹⁸ and offers SIEM/SOAR connectors for tools like Splunk and Google Chronicle.¹⁹
Best For: Large enterprises needing comprehensive email hygiene alongside threat protection.
3. Microsoft Defender for Office 365
Microsoft Defender for Office 365 Plan 1 offers native email protection through Safe Attachments sandbox detonation,²⁰ Safe Links time-of-click URL protection,²¹ and anti-phishing policies with impersonation detection.²² Plan 2 adds Threat Explorer for advanced threat hunting²³ and Automated Investigation and Response capabilities.²⁴
Native integration with Microsoft Defender XDR enables unified incident investigation across email, endpoints, identities, and cloud apps.²⁵
Best For: Organizations standardizing on the Microsoft security stack who want consolidated security operations.
4. Mimecast
Mimecast provides cloud gateway protection with NLP threat detection, time-of-click URL analysis, and attachment protection via transcription.²⁶ Attachments are converted into a safe, read-only format with no delivery delay. Users can request on-demand sandboxing of the original file, or Mimecast can pre-emptively sandbox attachments before delivery (which may add delay).²⁷
Integrated archiving and compliance capabilities address regulatory requirements with secure storage for email, files, and conversations.²⁸
Best For: Organizations needing email security plus compliance, archiving, and e-discovery capabilities in a unified platform.
5. IRONSCALES
IRONSCALES combines AI-based detection with community-driven threat intelligence.²⁹ The Themis engine detects and clusters BEC, account takeover, and GenAI-powered phishing threats, with configurable automation ranging from analyst-in-the-loop review to full autonomy.³⁰ A separate deepfake protection module analyzes video and audio content for AI-generated impersonation.³¹
The platform connects to Microsoft 365 via API without MX record changes, deploying inbox-level defense without disrupting mail flow.³² Integrated phishing simulation uses GPT-powered scenarios tailored to each user's role and risk profile.³³
Best For: Organizations seeking inbox-level defense with integrated training and autonomous remediation.
6. Barracuda
Barracuda's Integrated Email Protection deploys via API integration with Microsoft 365 in minutes, without MX record changes or mail-flow disruption.³⁴ Its separate Email Gateway Defense product offers inline gateway protection with automatic quarantine of suspicious messages and alerts to administrators and users.³⁵
Best For: SMBs needing rapid deployment with minimal IT overhead.
7. Darktrace
Darktrace provides detection across cloud, endpoint, email, network, and OT environments as part of the ActiveAI Security Platform.³⁶ Self-learning AI establishes behavioral baselines across users and entities, assessing interactions against dynamic baselines rather than relying on static rules.³⁷ Native integrations span SIEM/SOAR tools such as Azure Sentinel and Splunk, plus cloud/SaaS platforms including Google Workspace and Microsoft 365.³⁸
Best For: Organizations wanting integrated network and email threat detection.
8. Material Security
Material Security takes a data-centric approach to email protection, focusing on securing sensitive content within mailboxes. The platform redacts sensitive information from emails³⁹ and requires additional authentication to access protected content.⁴⁰
Best For: Organizations prioritizing data protection and insider threat mitigation alongside traditional email security.
How to Evaluate Email Security Alternatives
Email security platform selection depends on detection methodology, deployment model, and operational overhead. Each affects your team's ability to prevent breaches and respond efficiently.
Detection Methodology
Detection approaches fall into three categories. Rule-based systems typically require ongoing maintenance and detection engineering resources. They are effective against known patterns but may struggle with zero-day attacks, payloadless BEC, and AI-generated phishing.
Behavioral AI is designed to adapt autonomously by correlating signals from a variety of data sources and behavioral signals which allow it to catch novel threats that lack IOCs. Hybrid approaches combine signature-based filtering with behavioral analysis for layered protection across known and unknown threats.
Deployment and Integration
API-native deployment integrates directly with Microsoft 365 and Google Workspace without mail flow changes. Gateway deployment can provide pre-delivery blocking but requires infrastructure configuration. Consider integration depth with existing SIEM/SOAR platforms.
Operational Overhead
Evaluate SOC workload impact and whether this allows for proactive or reactive protection. Some platforms rely on ongoing customer tuning, while others are designed to continuously update protection with minimal intervention. Organizations using behavioral AI can often reduce reactive incident-response efforts by automating the manual triage that reactive interventions require.
Finding the Right Fit for Your Security Team
Email security platform selection depends on your detection management resources, platform coverage needs, or novel threat requirements. Sublime's agentic, detection-as-code model empowers engineers who want hands-on control, while behavioral AI platforms can deliver autonomous protection for teams prioritizing efficiency and proactive protection.
Evaluate alternatives based on deployment speed, integration capabilities, and the operational burden your team can sustain. Request a demo to see why more than 5,000 organizations, including 30% of the Fortune® 500 trust Abnormal.⁴¹
This guide is published by Abnormal AI, which is also included in the comparison. Descriptions and characterizations of other vendors reflect Abnormal's assessment of publicly available information as of October 2026 and may be subject to change. Comparative statements, including any "best for" characterizations, reflect Abnormal's own opinion and evaluation criteria, not an independent or third-party assessment. Sublime Security, Proofpoint, Microsoft, Mimecast, IRONSCALES, Barracuda, Darktrace, and Material Security are trademarks of their respective owners; references to them are for informational comparison purposes only and do not imply affiliation with or endorsement by those companies.
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Sublime Security, "Sublime for Email Detection Engineers," https://sublime.security/use-cases/detection-engineering-custom-policies/ (accessed September 2026).
Sublime Security, "MQL Detection Rules," https://docs.sublime.security/docs/detection-rules (updated June 2026).
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Gartner, Magic Quadrant™ for Email Security, Max Taggett and Nikul Patel, https://abnormal.ai/resources/gartner-magic-quadrant-email-security, December 1, 2025. GARTNER and MAGIC QUADRANT are registered trademarks of Gartner, Inc. and/or its affiliates and are used herein with permission. Gartner does not endorse any vendor depicted in its research and does not advise technology users to select only vendors with the highest ratings. Gartner research consists of opinions of Gartner's research organization and should not be construed as statements of fact.
Gartner Peer Insights, Voice of the Customer for Email Security, Peer Community Contributors, https://abnormal.ai/resources/analyst-research/gartner-peer-insights-voice-of-the-customer-email-security, June 30, 2026. GARTNER and PEER INSIGHTS are registered trademarks of Gartner, Inc. and/or its affiliates and are used herein with permission. All rights reserved. Gartner Peer Insights content consists of the opinions of individual end users based on their own experiences and should not be construed as statements of fact, nor do they represent the views of Gartner or its affiliates. Gartner does not endorse any vendor, product, or service depicted in this content.
Gartner Peer Insights, Voice of the Customer for Email Security, Peer Community Contributors, http://abnormal.ai/blog/abnormal-named-gartner-peer-insights-customers-choice-2026, June 30, 2026. GARTNER and PEER INSIGHTS are registered trademarks of Gartner, Inc. and/or its affiliates and are used herein with permission. All rights reserved. Gartner Peer Insights content consists of the opinions of individual end users based on their own experiences and should not be construed as statements of fact, nor do they represent the views of Gartner or its affiliates. Gartner does not endorse any vendor, product, or service depicted in this content.
Abnormal AI, "Abnormal AI Secures Spot on Forbes 2025 Cloud 100 for Third Year Running," https://abnormal.ai/newsroom/press-releases/abnormal-secures-spot-forbes-2025-cloud-100 (Sep 3, 2025).
CNBC, "Abnormal AI: 2026 CNBC Disruptor 50," https://www.cnbc.com/2026/05/19/abnormal-ai-cnbc-disruptor-50-ranking.html (May 19, 2026).
Abnormal AI, "Abnormal AI Expands Its AI Security Suite Powered by Its Behavioral Security Platform," http://abnormal.ai/newsroom/press-releases/abnormal-ai-expands-its-ai-security-suite (Sep 24, 2026).
AI Phishing Coach capabilities may vary by deployment and are subject to ongoing product availability; contact your Abnormal representative for current feature details.
AI Phishing Coach ships in two tiers: Core (Generally Available) and Advanced (Pre-GA). Advanced personalization features are subject to tier availability.
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