Improving email security outcomes with real-world Microsoft Defender insights
Microsoft's quarterly benchmark claims Defender missed 55.4% fewer high-severity email threats than the next-closest secure email gateway.
Microsoft published its fifth consecutive quarterly email security benchmark covering May through July 2026, reporting Defender missed 221 high-severity threats per 1,000 protected users, 55.4% fewer than the next-closest SEG vendor, and caught 92% of post-delivery malicious messages. Microsoft notes missed threats are rising across vendors as AI helps attackers craft more convincing impersonation attempts. The report also highlights product updates, including a redesigned AI model stack that reduced false negatives by roughly two-thirds and new prompt injection protection for Copilot and other AI systems that process email.
- Defender missed 221 high-severity threats per 1,000 users versus the next-closest SEG
- Caught 92% of post-delivery malicious messages during the May-July 2026 benchmark
- Missed threats are increasing as AI enables more convincing attacker impersonation
- New prompt injection protection aims to shield Copilot and agents from malicious email instructions
- Vendors
- Microsoft
- Products
- Microsoft DefenderOutlookCopilot
From the original article
4 min read at microsoft.com
The latest email security benchmarking reports show strong Microsoft Defender performance across pre-delivery and post-delivery scenarios and reveal where threats and defenses continue to evolve. The post Improving email security outcomes with real-world Microsoft Defender insights appeared first on Microsoft Security Blog.
By Rob Lefferts · microsoft.com
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