Microsoft Security Blog
Your source for the latest in cybersecurity
Featured Posts
Reimagining the SOC for the agentic era in Microsoft Defender
We are announcing ISOC in Microsoft Defender: a foundation built for agentic security that brings leading solutions for SIEM and threat protection together.
What’s new in Microsoft Security: September 2026
This month’s updates help you discover and control local AI agents, extend Zero Trust to agent traffic, and strengthen SOC foundations.
From guidance to action: Security fundamentals that materially reduce risk
AI has made fundamental changes to the operating environment for cybersecurity.
Improving email security outcomes with real-world Microsoft Defender insights
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.
Threat intelligence
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Unauthenticated command injection on internet-facing mail servers: tracking CVE-2026-73570
Microsoft Threat Intelligence examines CVE-2026-73570 exploitation in Zimbra, including observed attack paths, detection opportunities, and mitigation guidance. -
Phishing Abuses RMM Tools for Persistent Access
Microsoft observed phishing campaigns that abused MSP360 RMM to deploy ScreenConnect, creating redundant remote-access channels for follow-on activity -
Star Blizzard refines phishing and malware delivery with the RedFlick technique
Since January 2026, Microsoft has observed Russian state threat actor Star Blizzard evolve their detection evasion capabilities through large-scale phishing campaigns, the use of accounts on compromised websites, and a novel malware delivery technique, tracked by Microsoft as “RedFlick”.
Stay ahead of threats
Get expert insights, threat intelligence, and the latest cybersecurity reports from Security Insider.
AI and machine learning
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Storm-3168: Agentic-driven cloud attacks using compromised service principals
Microsoft details JADEPUFFER-linked Azure reconnaissance, resource deletion, and credential access using compromised service principals, identifying the activity as associated with Storm-3168 and providing guidance for defenders. -
What’s new in Microsoft Security: September 2026
This month’s updates help you discover and control local AI agents, extend Zero Trust to agent traffic, and strengthen SOC foundations. -
Reimagining the SOC for the agentic era in Microsoft Defender
We are announcing ISOC in Microsoft Defender: a foundation built for agentic security that brings leading solutions for SIEM and threat protection together.
Modernize your security operations center
Confidently secure your multicloud, multiplatform environment with Microsoft Sentinel – a cloud-native security information and event management (SIEM) solution.
Latest posts
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Unauthenticated command injection on internet-facing mail servers: tracking CVE-2026-73570
Microsoft Threat Intelligence examines CVE-2026-73570 exploitation in Zimbra, including observed attack paths, detection opportunities, and mitigation guidance. -
Phishing Abuses RMM Tools for Persistent Access
Microsoft observed phishing campaigns that abused MSP360 RMM to deploy ScreenConnect, creating redundant remote-access channels for follow-on activity -
Beyond source code: A path to the keys to the kingdom
Explore how Storm-3068 turned a compromised identity into broader cloud access and the steps organizations can take to defend their identities, pipelines, and cloud infrastructure. -
Star Blizzard refines phishing and malware delivery with the RedFlick technique
Since January 2026, Microsoft has observed Russian state threat actor Star Blizzard evolve their detection evasion capabilities through large-scale phishing campaigns, the use of accounts on compromised websites, and a novel malware delivery technique, tracked by Microsoft as “RedFlick”. -
NeedyMantis: Unpacking a post-compromise malware family used in targeted operations
Microsoft Threat Intelligence identified NeedyMantis, a modular post-compromise malware framework used in targeted intrusions that combines custom loaders, encrypted archives, and extensible components to maintain long-term access and support follow-on operations. -
Storm-3168: Agentic-driven cloud attacks using compromised service principals
Microsoft details JADEPUFFER-linked Azure reconnaissance, resource deletion, and credential access using compromised service principals, identifying the activity as associated with Storm-3168 and providing guidance for defenders.