How public-private partnerships can combat cyber adversaries

For several years now, policymakers and practitioners from governments, CERTs, and the security industry have been speaking about the importance of public-private partnerships as an essential part of combating cyber threats. It is impossible to attend a security conference without a keynote...

Detonating a bad rabbit: Windows Defender Antivirus and layered machine learning defenses

Windows Defender Antivirus uses a layered approach to protection: tiers of advanced automation and machine learning models evaluate files in order to reach a verdict on suspected malware. While Windows Defender AV detects a vast majority of new malware files at first sight, we always strive to...

Hunting MacSync Stealer infrastructure through behavioral pivots

In this article 1. Activity overview 2. Discovery of additional rotating infrastructure 3. Attack chain overview 4. Mitigation and protection guidance 5. References 6. Learn more MacSync Stealer is a macOS-focused information stealer that relies on changing infrastructure to deliver payloads,...

Least privilege for AI agents: Identity, access, and tool binding

In this article 1. Real-world scenarios 2. Best Practices: Identity + RBAC + Scope + Safe Tool Binding 3. Looking Ahead AI agents aren't only smarter API callers. They plan, chain actions across systems, and invoke tools in sequences while no single human explicitly approves each step. The...

Improving security posture across the Microsoft partner ecosystem

The Deputy CISO blog series is where Microsoft Deputy Chief Information Security Officers CISOs share their thoughts on what is most important in their respective domains. In this series, you will get practical advice, tactics to start and stop deploying, forward-looking commentary on where the...

Microsoft Defender email security benchmarking: Key insights from one year of data

Microsoft publishes quarterly email security benchmarking data comparing Microsoft Defender against secure email gateway SEG and integrated cloud email security ICES vendors using real-world threat telemetry. A year ago, we set out to change how email security effectiveness is measured. With our...

When configuration becomes a vulnerability: Exploitable misconfigurations in AI apps

In this article 1. Background 2. What is an exploitable misconfiguration? 3. Exploitable misconfigurations in popular AI applications 4. Minimizing the risk: Practical deployment guidance 5. How Microsoft Defender for Cloud helps detect exposures in Kubernetes 6. Learn more AI and agentic...

Undermining the trust boundary: Investigating a stealthy intrusion through third-party compromise

In this article 1. Abuse of trusted relationships as an attack delivery mechanism 2. Methods, tools, and access strategies 3. Campaign conclusion 4. Microsoft Defender detection and hunting guidance In recent years, many sophisticated intrusions have increasingly avoided using noisy exploits,...

Breaking the code: Multi-stage ‘code of conduct’ phishing campaign leads to AiTM token compromise

In this article 1. Multi-step social engineering campaign leading to credential theft 2. Mitigation and protection guidance 3. Microsoft Defender detections 4. Hunting queries 5. Indicators of compromise Phishing campaigns continue to improve sophistication and refinement in blending social...

What’s new, updated, or recently released in Microsoft Security

New capabilities in Microsoft Agent 365; new Microsoft Defender and GitHub integration At Microsoft, security innovations are purpose-built to help every organization protect end-to-end with the speed and scale of AI. Our vision is simple: security should be ambient and autonomous, just like the ...

Detection strategies across cloud and identities against infiltrating IT workers

In this article 1. Attack chain overview 1. Activities in pre-recruitment phase 2. Activities in recruiting phase 3. Activities in post-recruitment phase 2. Mitigation and protection guidance 3. Microsoft Defender XDR detections The shift to remote and hybrid work since the pandemic expanded glob...

Containing a domain compromise: How predictive shielding shut down lateral movement

In this article 1. Predictive shielding overview 2. Attack chain overview 3. How predictive shielding changed the outcome 4. MITRE ATT&CK® techniques observed 5. Learn more In identity-based attack campaigns, any initial access activity can turn an already serious intrusion into a critical incide...

Building your cryptographic inventory: A customer strategy for cryptographic posture management

Post-quantum cryptography PQC is coming—and for most organizations, the hardest part won’t be choosing new algorithms. It will be finding where cryptography is used today across applications, infrastructure, devices, and services so teams can plan, prioritize, and modernize with confidence. At...

Investigating Storm-2755: “Payroll pirate” attacks targeting Canadian employees

In this article 1. Storm-2755’s attack chain 2. Defending against Storm-2755 and AiTM campaigns 3. Microsoft Defender detection and hunting guidance 4. Indicators of compromise Microsoft Incident Response – Detection and Response Team DART researchers observed an emerging, financially motivated...

How Microsoft Defender protects high-value assets in real-world attack scenarios

In this article 1. Using asset context to strengthen detection 2. How high-value asset protection works 3. Real-world high-value asset protection scenarios 4. Protecting your HVAs 5. Learn more High-value assets including domain controllers, web servers, and identity infrastructure are frequent...

Secure agentic AI for your Frontier Transformation

Today we shared the next step to make Frontier Transformation real for customers across every industry with Wave 3 of Microsoft 365 Copilot, Microsoft Agent 365, and Microsoft 365 E7: The Frontier Suite. Introducing the First Frontier Suite built on Intelligence and Trust As our customers rapidly...

OAuth redirection abuse enables phishing and malware delivery

Microsoft observed phishing-led exploitation of OAuth’s by-design redirection mechanisms. The activity targets government and public-sector organizations and uses silent OAuth authentication flows and intentionally invalid scopes to redirect victims to attacker-controlled infrastructure without...

Threat modeling AI applications

Proactively identifying, assessing, and addressing risk in AI systems We cannot anticipate every misuse or emergent behavior in AI systems. We can , however, identify what can go wrong, assess how bad it could be, and design systems that help reduce the likelihood or impact of those failure modes...

Manipulating AI memory for profit: The rise of AI Recommendation Poisoning

That helpful "Summarize with AI" button? It might be secretly manipulating what your AI recommends. Microsoft security researchers have discovered a growing trend of AI memory poisoning attacks used for promotional purposes, a technique we call AI Recommendation Poisoning. Companies are embedding...

A one-prompt attack that breaks LLM safety alignment

Large language models LLMs and diffusion models now power a wide range of applications, from document assistance to text-to-image generation, and users increasingly expect these systems to be safety-aligned by default. Yet safety alignment is only as robust as its weakest failure mode. Despite...

Microsoft named an overall leader in KuppingerCole Leadership Compass for Generative AI Defense

Today, we are proud to share that Microsoft has been recognized as an overall leader in the KuppingerCole Leadership Compass for Generative AI Defense GAD, an independent report from a leading European analyst firm. This recognition reinforces the work we’ve been doing to deliver enterprise-ready...

Charting the future of SOC: Human and AI collaboration for better security

Security operations centers are under pressure from unprecedented scale and complexity. Speed, precision, and consistency matter more than ever, and AI is everywhere—but hype alone doesn’t solve the challenge. This blog shares our journey and insights from building autonomous AI agents for MDR...

Investigating targeted “payroll pirate” attacks affecting US universities

Microsoft Threat Intelligence has observed a financially motivated threat actor that we track as Storm-2657 compromising employee accounts to gain unauthorized access to employee profiles and divert salary payments to attacker-controlled accounts. These types of attacks have been dubbed “payroll...

XCSSET evolves again: Analyzing the latest updates to XCSSET’s inventory

Microsoft Threat Intelligence has identified yet another XCSSET variant in the wild that introduces further updates and new modules beyond those detailed in our March 2025 blog post. The XCSSET malware is designed to infect Xcode projects, typically used by software developers, and run while an...

Storm-0501’s evolving techniques lead to cloud-based ransomware

Microsoft Threat Intelligence has observed financially motivated threat actor Storm-0501 continuously evolving their campaigns to achieve sharpened focus on cloud-based tactics, techniques, and procedures TTPs. While the threat actor has been known for targeting hybrid cloud environments, their...

Think before you Click(Fix): Analyzing the ClickFix social engineering technique

Over the past year, Microsoft Threat Intelligence and Microsoft Defender Experts have observed the ClickFix social engineering technique growing in popularity, with campaigns targeting thousands of enterprise and end-user devices globally every day. Since early 2024, we’ve helped multiple custome...

Microsoft’s Secure by Design journey: One year of success

Cybersecurity is one of the top risks facing businesses. Organizations are struggling to navigate the ever-evolving cyberthreat landscape in which 600 million identity attacks are carried out daily.1 The median time for a cyberattacker to access private data from phishing is 1 hour and 12 minutes...

How cyberattackers exploit domain controllers using ransomware

In recent years, human-operated cyberattacks have undergone a dramatic transformation. These attacks, once characterized by sporadic and opportunistic attacks, have evolved into highly sophisticated, targeted campaigns aimed at causing maximum damage to organizations, with the average cost of a...

Join us at InfoSec Jupyterthon 2022

Notebooks are gaining popularity in InfoSec. Used interactively for investigations and hunting or as scheduled processing jobs, notebooks offer plenty of advantages over traditional security operations center SOC tools. Sitting somewhere between scripting/macros and a full-blown development...

Data governance: 5 tips for holistic data protection

Your data is a strategic asset. To benefit your business, data requires strict controls around structure, access, and lifecycle. However, most security leaders have doubts about data security—nearly 70 percent of chief information security officers CISOs expect to have their data compromised in a...

Microsoft best practices for managing IoT security concerns

The Internet of Things, or IoT, has expanded beyond the mere concept that it was when first introduced. IoT is now part of most individuals’ daily activities, from smart speakers and thermostats to smartwatches and vehicles. IoT devices and systems bring massive convenience and functionality. IoT...

Announcing Microsoft Defender ATP for Mac and new Threat and Vulnerability Management capabilities

On February 28, 2019, we announced Microsoft Threat Experts, a new managed hunting service within the Microsoft 365 Security portfolio that enables customers to extend their expertise and insights with the help of Microsoft security professionals. This release showcased our philosophy that securi...

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

In this article 1. Attack chain overview 2. Mitigation and protection guidance 3. Indicators of compromise IOC 4. Microsoft Defender XDR detections 5. Advanced hunting queries 6. Learn more Microsoft Threat Intelligence identified a large-scale npm supply chain attack affecting more than 400...

Enhancing AI security through global AI red teaming

In this article 1. Building a global alliance 2. What the research focuses on 3. Why this matters Most AI safety testing still happens inside the walls of individual organizations. That has resulted in a fundamental disconnect: many of the highest-risk failure modes in modern AI systems require...

Microsoft Entra ID security updates: Passkeys are the default authentication method in Entra ID

As identity attacks grow more sophisticated in the AI era, organizations need stronger authentication methods that protect users from phishing, credential theft, and social engineering. To address these evolving threats, Microsoft Entra ID is updating its authentication experience by making...

Protecting Microsoft at AI speed: How SFI proactively hardens our cloud

AI models have reached a threshold where they exhibit expert-level capabilities in vulnerability discovery, exploit chaining, and proof-of-concept generation. As AI-powered vulnerability discovery matures, every organization that builds or runs software at scale needs continuous proactive...

5 insights from Frost & Sullivan’s 2025 Frost Radar™ for Cloud Security Posture Management

Cloud security posture management CSPM is being redefined as two forces collide: Cloud environments are becoming more interconnected—spanning workloads, identities, data, APIs, and development pipelines—while security teams must reduce risk faster with fewer tools and less time. Frost & Sullivan’...

Microsoft a Leader in The Forrester Wave™ for Endpoint Management Platforms

The endpoint management category is being redefined in real time. Organizations no longer need tools that only inventory devices or enforce configuration policies; they need a platform that connects identity, security, compliance, and AI governance across every endpoint where work happens...

8 best practices for CISOs conducting risk reviews

The Deputy CISO blog series is where Microsoft Deputy Chief Information Security Officers CISOs share their thoughts on what is most important in their respective domains. In this series, you will get practical advice, tactics to start and stop deploying, forward-looking commentary on where the...

SOHO router compromise leads to DNS hijacking and adversary-in-the-middle attacks

In this article 1. DNS hijacking attack chain: From compromised devices to AiTM and other follow-on activity 2. Mitigation and protection guidance 3. Microsoft Defender detection and hunting guidance Executive summary Forest Blizzard, a threat actor linked to the Russian military, has been...

Cookie-controlled PHP webshells: A stealthy tradecraft in Linux hosting environments

In this article 1. Cookie-controlled execution behavior 2. Observed variants of cookie-controlled PHP web shells 3. Mitigation and protection guidance 4. Microsoft Defender XDR detections 5. Microsoft Security Copilot prompts 6. Microsoft Defender XDR threat analytics 7. MITRE ATT&CK™ Techniques...

Addressing the OWASP Top 10 Risks in Agentic AI with Microsoft Copilot Studio

Agentic AI is moving fast from pilots to production. That shift changes the security conversation. These systems do not just generate content. They can retrieve sensitive data, invoke tools, and take action using real identities and permissions. When something goes wrong, the failure is not limit...

New Microsoft Purview innovations for Fabric to safely accelerate your AI transformation

As organizations adopt AI, security and governance remain core primitives for safe AI transformation and acceleration. After all, data leaders are aware of the notion that: Your AI is only as good as your data. Organizations are skeptical about AI transformation due to concerns of sensitive data...

From transparency to action: What the latest Microsoft email security benchmark reveals

In our last benchmarking post, Clarity in complexity: New insights for transparent email security ,1 we shared why transparency matters more than ever in email security and how clear, consistent benchmarking helps security teams cut through noise and make confident decisions. Today, we’re...

From transparency to action: What the latest Microsoft email security benchmark reveals

In our last benchmarking post, Clarity in complexity: New insights for transparent email security ,1 we shared why transparency matters more than ever in email security and how clear, consistent benchmarking helps security teams cut through noise and make confident decisions. Today, we’re...

Detecting and analyzing prompt abuse in AI tools

This second post in our AI Application Security series is all about moving from planning to practice. AI Application Series 1: Security considerations when adopting AI tools established how AI adoption expands the attack surface and our threat-modelling guidance on the Microsoft security blog...

New e-book: Establishing a proactive defense with Microsoft Security Exposure Management

Effective exposure management begins by illuminating and hardening risks across the entire attack surface. Some of the most meaningful shifts in security happen quietly—when teams take a clear look at their exposure landscape and acknowledge the gap between where they stand today and where they...

Top 10 actions to build agents securely with Microsoft Copilot Studio

Organizations are rapidly adopting Copilot Studio agents, but threat actors are equally fast at exploiting misconfigured AI workflows. Mis-sharing, unsafe orchestration, and weak authentication create new identity and data‑access paths that traditional controls don’t monitor. As AI agents become...

Your complete guide to Microsoft experiences at RSAC™ 2026 Conference

The era of AI is reshaping both opportunity and risk faster than any shift security leaders have seen. Every organization is feeling the momentum; and for security teams, the question is no longer if AI will transform their work, but how to stay ahead of what comes next. At Microsoft, we see this...

Resurgence of a multi‑stage AiTM phishing and BEC campaign abusing SharePoint

Microsoft Defender Researchers uncovered a multi‑stage adversary‑in‑the‑middle AiTM phishing and business email compromise BEC campaign targeting multiple organizations in the energy sector, resulting in the compromise of various user accounts. The campaign abused SharePoint file‑sharing services...