What’s new in Microsoft Security: September 2026
Summary
Microsoft has released security updates to help organizations manage AI agents running on employee devices and networks. The updates include tools to discover and control these agents, prevent sensitive data from being shared to unauthorized AI tools, and improve how security teams investigate threats using AI-generated analysis. Microsoft Purview and Microsoft Entra now enforce data security policies at the network layer, stopping employees or agents from uploading sensitive documents to risky destinations before the data leaves the organization.
Solution / Mitigation
Several mitigations are explicitly mentioned: (1) Microsoft Purview and Microsoft Entra Global Secure Access can "block" sensitive data "from being shared to risky destinations" and "stop the transfer before the data leaves" if an employee or agent tries to upload sensitive documents to unsanctioned AI tools. (2) Microsoft Defender with Microsoft Security Copilot delivers "AI-generated explanations" of sandboxing results to help SOC teams investigate faster. (3) Microsoft Purview auto-labeling automatically applies data security controls to sensitive content at scale. (4) Microsoft Purview eDiscovery now supports search, hold, review, and export of content from AI-powered experiences like Microsoft Loop and Copilot Pages. (5) Microsoft Purview Data Lifecycle Management allows administrators to archive inactive content and use Priority Cleanup to permanently delete stale content so it is no longer discoverable in searches or AI indexing.
Classification
Affected Vendors
Related Issues
Original source: https://www.microsoft.com/en-us/security/blog/2026/09/24/whats-new-in-microsoft-security-september-2026/
First tracked: September 24, 2026 at 02:01 PM
Classified by LLM (prompt v3) · confidence: 85%