Microsoft Defender for Office 365 alternatives

Microsoft Defender for Office 365 is a solid choice, but not for everyone. Google Workspace organizations, and teams whose main worry is pure social-engineering payroll diversion, where a behavioral layer earns its keep. Here's what to look at instead.

Editor's Pick

Sublime Security

Serious BEC defense a small team can actually turn on: free for 100 mailboxes, no MX change

Genuinely free for your first 100 mailboxes, no credit card and no MX change. Above that it's a paid, quote-based subscription priced per mailbox, contact the vendor for current pricing. A free, open-source self-hosted version of the platform is available on GitHub for teams that want to run and extend it themselves.8.4/10

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Abnormal AI

Stops the 'update my direct deposit' email before payroll ever sees it

Contact the vendor for current pricing — Abnormal is premium, quote-only email security with no free tier, priced per mailbox on employee count plus paid onboarding (professional services commonly $5k-$25k+). Reported per-mailbox rates work out to a few dollars a month, so a 200-mailbox company should budget low five figures a year before services.8.0/10

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IRONSCALES

Per-seat BEC and account-takeover protection priced for SMBs and the MSPs that serve them

Per-user monthly subscription across three tiers (Protect, Email Protect, Complete Protect). IRONSCALES doesn't publish seat prices on its own site, but third-party listings consistently put them around $3.89, $5.49-5.99, and $7.29 per user per month respectively, confirm your quote directly. Free trial, no free tier. An MSP partner program means your IT provider can often add it for you.7.7/10

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