Abnormal AI vs Microsoft Defender for Office 365
Before you shop for either, check whether you're already paying for one of them: Defender for Office 365 Plan 1 comes bundled inside Microsoft 365 Business Premium's $22/user/month, and most tenants have never turned on its anti-phishing and impersonation policies. That's the honest first move, not a purchase. Once you've done that, the gap that's left is real: Defender's center of gravity is malware, malicious links, and broad phishing, while the pure social-engineering 'change my direct deposit' email, no link, no attachment, just a convincing ask, is exactly what Abnormal's behavioral modeling is built to catch and Defender's defaults tend to miss. Abnormal costs real money with no public number and a paid onboarding process; Defender is a switch you may have already bought. Turn the switch on first. Layer Abnormal on top only if payroll diversion specifically is still getting through.
| Pricing model | custom-quote | subscription |
| Starting point | 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+) | Bundled into Microsoft 365 Business Premium ($22/user/mo), so many SMBs already own Plan 1 |
| Best for | Any business that processes direct-deposit change requests by email or Slack and wants to stop social-engineering-driven payroll diversion before it happens. | Microsoft 365 shops that should turn on and tune the BEC-relevant protection they already own before buying anything dedicated. |
| Countries | United States, Canada, United Kingdom, Australia | United States, United Kingdom, Canada, Australia |
| Editorial score | 8/10 | 7/10 |
Abnormal AI
- Targets the single most common real-world payroll fraud vector for SMBs: social engineering by email
- Behavioral detection catches attacks with no malicious payload, which slip past traditional email security
- Sits upstream of payroll, stopping the fraudulent request before it's ever acted on
- This is an email security purchase, not a payroll or HR tool, different budget owner and evaluation process
- No visibility into payroll data itself, it only stops the request from being convincing
- Enterprise pricing and sales process, no public numbers to compare against
Microsoft Defender for Office 365
- You may already own Plan 1 inside Business Premium, protection you've paid for and can simply switch on
- Native to Microsoft 365, so there's no third-party routing or MX change to deploy
- Covers the broad email threat surface (malware, malicious URLs, impersonation), not only BEC
- A broad email-security add-on, not a purpose-built behavioral payroll-diversion tool
- The payload-free 'change my direct deposit' email is where behavioral specialists (Sublime, Abnormal) still catch more
- Real value takes configuring the anti-phishing and impersonation policies, the defaults alone leave gaps