KnowBe4 Cloud Email Security

What it does

KnowBe4 Cloud Email Security is an Integrated Cloud Email Security (ICES) platform that guards Microsoft 365 mailboxes against inbound and outbound email threats. It combines three modules: Defend for inbound anti-phishing, Prevent for outbound data loss, and Protect for policy-based email encryption. Rather than relying on signatures or blocklists, the platform applies self-learning behavioral AI and natural language processing to model each user's normal communication patterns, catching business email compromise, account takeover, and AI-generated impersonation that gateway tools miss.

How it works

The platform connects to Microsoft 365 through the Microsoft Graph API as a post-delivery layer, or runs as an inline SMTP gateway, so it deploys without changing MX records. Defend ingests historical mail to build per-user and per-vendor behavioral baselines, then applies natural language processing and semantic analysis to flag phishing, deepfake-driven impersonation, and zero-day account compromise, inserting color-coded warning banners into Outlook messages across 13 languages. Prevent analyzes outbound mail to stop misdirected messages and data exfiltration, while Protect adds policy-based encryption. User-reported messages feed detection, and confirmed threats are remediated retroactively across all inboxes.

Credentials and traction

KnowBe4 Cloud Email Security is SOC 2 Type II certified, part of KnowBe4's ISO 27001 audited information security program. It was named a Leader in the 2025 Gartner Magic Quadrant for Email Security Platforms, its second consecutive year in the Leaders quadrant after placing in the inaugural 2024 edition as Egress. The platform targets enterprises standardized on Microsoft 365 that need behavioral defense against phishing, business email compromise, and outbound data loss.