Latest coverage for Microsoft

From late April 2026 to mid-June 2026, Microsoft Defender Experts observed increased ACR Stealer activity across customer environments. These campaigns are successfully using ClickFix lures to steal browser credentials, authentication tokens, and sensitive documents from enterprise environments. The post ACR Stealer: Two observed intrusion chains amid increased threat activity appeared first on Microsoft Security Blog.

As AI agents become more autonomous, strong identity, access, and auditing controls are critical to keeping them secure. The post Least privilege for AI agents: Identity, access, and tool binding appeared first on Microsoft Security Blog.

Threat actors compromised AsyncAPI packages and weaponized trusted CI/CD workflows to distribute malware through npm. This analysis breaks down the attack chain, payload delivery, and recommended defenses. The post Unpacking the AsyncAPI npm supply chain compromise and import-time payload delivery appeared first on Microsoft Security Blog.

Security teams have never had more visibility, yet rarely have they felt more uncertain. Signal pours in from endpoints, identities, cloud workloads, and a sprawling mix of third-party tools. The post Turning threat intelligence into decisive action with Defender Experts appeared first on Microsoft Security Blog.

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. The post Defending SaaS-based applications against ShinyHunters OAuth abuse appeared first on Microsoft Security Blog.

GigaWiper, also tracked as BLUERABBIT, is a destructive backdoor that combines multiple wiping and ransomware-like capabilities into a single operational platform. This blog analyzes how the malware incorporates code from several previously separate malware families and provides guidance to help defenders detect and defend against similar threats. The post GigaWiper: Anatomy of a destructive backdoor assembled from multiple malware appeared first on Microsoft Security Blog.

MCP tool poisoning turns trusted AI agents into a control plane for data loss. Learn how threat actors manipulate tool descriptions to trigger unauthorized actions, and how to detect, contain, and prevent it. The post Securing AI agents: When AI tools move from reading to acting appeared first on Microsoft Security Blog.

A malicious Chromium-based extension that spoofs the AI-powered answer engine Perplexity AI redirects browser search traffic using MV3 APIs and intermediary infrastructure. The post Chromium extension uses AI‑related branding to redirect browser search appeared first on Microsoft Security Blog.

Microsoft Threat Intelligence identified an active multi-stage intrusion campaign targeting hospitality organizations in Europe and Asia. The campaign uses photo-themed ZIP archives and fake image shortcut files to deliver a persistent Node.js implant and evade detection. The post Photo ZIP campaign targeting hospitality industry delivers Node.js implant for persistent access appeared first on Microsoft Security Blog.

On June 24, 2026, Microsoft’s Digital Crimes Unit (DCU) facilitated the takedown, suspension, and blocking of domains that formed the backbone of the StealC and Amadey infrastructure. This blog is a technical breakdown of StealC and Amadey. The post StealC and Amadey: Breaking down infostealers and the cybercrime services that deliver them appeared first on Microsoft Security Blog.

What happens when threat actors target what AI remembers? Microsoft breaks down the risks and the defenses. The post Guarding AI memory appeared first on Microsoft Security Blog.

AutoJack is a novel exploit chain showing how a single malicious webpage can turn an AI browsing agent into a remote code execution vector on the host machine. By abusing trust in localhost, missing authentication, and unsafe parameter handling, attackers can trigger arbitrary process execution through AutoGen Studio’s MCP WebSocket. The research highlights a broader pattern - when agents can browse untrusted content and access local services, traditional boundaries like localhost are no longer secure. The post AutoJack: How a single page can RCE the host running your AI agent  appeared first on Microsoft Security Blog.

A poisoned npm package infected 140+ projects with a hidden payload. This report highlights how to detect, hunt, and defend against supply chain attacks using Microsoft Defender and actionable threat intelligence. The post From package to postinstall payload: Inside the Mastra npm supply chain compromise by Sapphire Sleet appeared first on Microsoft Security Blog.

Microsoft Threat Intelligence analyzed a cryptocurrency clipper campaign that combines clipboard theft, wallet replacement, Tor-based communications, and worm-like propagation. Beyond stealing cryptocurrency transactions, the malware establishes persistent access and enables follow-on activity through a lightweight backdoor capability. The post Crypto Clipper uses Tor and worm-like propagation for persistence and control appeared first on Microsoft Security Blog.

Learn how to investigate AI activity in Microsoft 365 Copilot and Azure AI services using a structured, telemetry-driven approach. This playbook helps security teams reconstruct events, assess data exposure, and detect potential threats faster. The post Reconstructing AI activity in investigations  appeared first on Microsoft Security Blog.

As threat actors operationalize AI to accelerate attacks, they are also leveraging the wider global interest around AI itself as a social engineering lure. The post AI brands as bait: How threat actors are using the AI hype in social engineering appeared first on Microsoft Security Blog.

Microsoft Threat Intelligence identified a prompt injection pathway in Claude Code GitHub Action that allowed access to workflow secrets under specific conditions. This research examines the attack chain, responsible disclosure process, Anthropic's mitigation, and guidance for securing AI-powered CI/CD workflows. The post Securing CI/CD in an agentic world: Claude Code Github action case appeared first on Microsoft Security Blog.

A surge in real-world attacks against agentic AI systems is reshaping how we think about risk. Based on 12 months of red teaming, this update introduces seven new failure modes, from supply chain compromise to goal hijacking, and the practical mitigations teams need now. The post Updating the taxonomy of failure modes in agentic AI systems: What a year of red teaming taught us  appeared first on Microsoft Security Blog.

A large-scale npm supply chain attack compromised over 90 versions of @redhat-cloud-services packages, silently infecting CI/CD environments and developer systems. The malicious code steals credentials from GitHub, cloud platforms, and local machines, then spreads like a worm by republishing trusted packages. Discover how the attack works, what data is at risk, and the steps you can take to protect your organization. The post Preinstall to persistence: Inside the Red Hat npm Miasma credential-stealing campaign appeared first on Microsoft Security Blog.

A dependency confusion campaign leveraged 33 malicious npm packages to collect reconnaissance data from developer and build environments. This report details the attack chain, observed tradecraft, and detection opportunities to help organizations identify and disrupt related activity. The post Malicious npm packages abuse dependency confusion to profile developer environments appeared first on Microsoft Security Blog.