Microsoft Defender

Microsoft Defender helps prevent, detect, and respond to attacks across devices, identities, apps, email, data, workloads, and clouds. Explore threat intelligence, capabilities, and real-world guidance to help you get more out of Defender.

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Modernize your Security Operations Center with Microsoft Sentinel

Microsoft Sentinel is a cloud-native SIEM solution powered by AI and automation that delivers intelligent security analytics across your entire enterprise.

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August 10 20 min read

DeadLock ransomware: Breaking down a Rust-based encryptor with decentralized recovery infrastructure

Microsoft Threat Intelligence examines DeadLock ransomware, an emerging financially motivated operation distinguished by its use of decentralized infrastructure to support victim communications, negotiations, and data leak operations alongside double extortion tactics used to pressure victims.
August 5 13 min read

From open lures to cloaked gates: How a macOS ClickFix campaign learned to hide

A macOS ClickFix campaign shifted tactics from openly serving infostealer lures to hiding them behind a browser-fingerprinting gate.
August 4 10 min read

ChainDrop supply chain compromise: Anatomy of a self-propagating worm

A credential-stealing worm hidden in more than 400 compromised npm packages automatically spread across software ecosystems by republishing malicious updates.
August 4 7 min read

128 Seconds to disruption: Microsoft Defender stops ransomware at QNET

Microsoft Defender automatically isolated a compromised QNET endpoint in 128 seconds, stopping a multi-stage attack before the payload could persist or spread.
Tailored AI insights from Microsoft Security Copilot

Empower your defenders to detect hidden patterns, harden defenses, and respond to incidents faster with generative AI.

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July 31 20 min read

CaptiveCrunch: Midnight Blizzard targets travelers worldwide for malware delivery and credential theft

Storm-2945, a sub-cluster of the Russian threat actor Midnight Blizzard, has been observed compromising the sign-in portals of hospitality-related organizations such as hotels since May 2026 in order to deliver malware to travelers and steal credentials in an operation we call CaptiveCrunch.
July 30 5 min read

What’s new in Microsoft Security: July 2026

This month’s updates help security and IT teams secure their AI environments, use AI to defend, and strengthen the foundations that AI-powered operations depend on.
July 23 17 min read

Email threat landscape: Q2 2026 trends and insights

In the second quarter of 2026, the continuing effects of Microsoft’s disruption of the Tycoon2FA phishing platform contributed to sustained declines in several major phishing techniques, while threat actors expanded into Teams-based social engineering and employed increasingly automated and multi-stage attack chains.
July 16 12 min read

ACR Stealer: Two observed intrusion chains amid increased threat activity

From late April 2026 to mid-June 2026, Microsoft Defender Experts observed increased ACR Stealer activity across customer environments.
Go beyond data protection with Microsoft Purview

Govern, protect, and manage all of your data with Microsoft Purview, comprehensive solutions to help give you better visibility and control.

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July 15 13 min read

Unpacking the AsyncAPI npm supply chain compromise and import-time payload delivery

Threat actors compromised AsyncAPI packages and weaponized trusted CI/CD workflows to distribute malware through npm.
July 15 3 min read

Turning threat intelligence into decisive action with Defender Experts

Security teams have never had more visibility, yet rarely have they felt more uncertain.
July 13 9 min read

Defending SaaS-based applications against ShinyHunters OAuth abuse

Microsoft Threat Intelligence identified threat actor activity with overlapping tradecraft commonly associated with ShinyHunters, including voice phishing (vishing), supply-chain compromise, and misconfigured guest access targeting SaaS-based applications.
July 9 16 min read

GigaWiper: Anatomy of a destructive backdoor assembled from multiple malware

GigaWiper, also tracked as BLUERABBIT, is a destructive backdoor that combines multiple wiping and ransomware-like capabilities into a single operational platform.