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Source: Microsoft Security Blog

14 stories in the last 30d

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DomainAllCyberAIWindow24h3d7d30dAllIn the wildImportant onlyShow duplicates
CategoryAllThreat actor 4Industry 3Phishing & fraud 3Tools 2AI safety & security 1Exploit / PoC 1
SeverityAllcritical 0high 5medium 3low 0info 6source: Microsoft Security Blog ✕

Passkey-themed social engineering leads to identity and cloud compromise

Microsoft tracks ongoing cloud intrusions where passkey-themed helpdesk lures enable AiTM credential theft, MFA persistence, and SharePoint data theft.

Microsoft Security Research is tracking active cloud-based intrusions, observed since May 2026, that begin with helpdesk impersonation calls and SMS lures urging urgent passkey, MFA, or SSO updates. The lures lead to adversary-in-the-middle phishing or device-code authentication flows that capture credentials and session tokens or grant actor access, after which the actors add authentication methods, conduct Microsoft Graph reconnaissance, and download SharePoint and OneDrive content via REST APIs. Phishing domains embed victim organization names as subdomains (e.g., contoso.add-passkey[.]com), are often registered with Nicenic, and go operational within hours. Microsoft advises revoking sessions and removing unauthorized authentication methods for confirmed compromises.

Microsoft Security Blogupdated · 4d agofirst · 6d agoThreat actor in the wild 13 sources2

Protecting organizations from AI-assisted executive impersonation and invoice fraud

Microsoft tracked a campaign of over one million AI-crafted CEO-impersonation emails seeking ~$50,000 ACH payments with fabricated ServiceNow invoices.

Between August 3 and 5, Microsoft detected a campaign of more than one million fraud emails, 87.7% of them targeting US enterprise users, sent through multiple third-party email delivery service accounts. The actor impersonated CEOs, CFOs, and presidents of targeted companies, urging accounts payable staff to process an ACH payment of nearly $50,000. Lures layered executive impersonation, lookalike domains, a fabricated ServiceNow 'Annual Subscription' invoice personalized to the recipient, and forged forwarded email threads; Microsoft found no evidence ServiceNow or the referenced executives were compromised. Microsoft observed indicators consistent with generative AI-assisted template creation, while leftover inconsistencies such as missing forwarding headers and mismatched display names gave defenders detection cues.

Microsoft Security Blog · 5d agoPhishing & fraud1

Detect and disrupt AI-themed attacks with Microsoft Defender

Microsoft Threat Intelligence reports criminal campaigns impersonating ChatGPT, Copilot, Claude, and DeepSeek in phishing, AiTM, and malvertising attacks reaching 100,000 emails daily.

Microsoft Threat Intelligence observed a growing set of campaigns that abuse trust in popular AI brands: a ChatGPT-themed phishing campaign sent up to 100,000 emails in one day to steal payment card data, and a Claude-themed campaign used adversary-in-the-middle techniques to harvest credentials and access tokens. Other campaigns included malvertising for a fake AI Windows plugin delivering the Vidar stealer and fraudulent DeepSeek installers distributed via GitHub. Initial access broker Storm-3075 used AI-themed malvertising to distribute payloads for multiple downstream actors, and Microsoft notes the AI services themselves were not compromised. Microsoft also details Defender protections such as Safe Links, Safe Attachments, and attack disruption against these multi-stage lures.

Microsoft Security Blog · 5d agoPhishing & fraud in the wild1

Threat Matrix: Mapping threats across cloud web applications

Microsoft released a Cloud Web Applications Threat Matrix, a MITRE ATT&CK-aligned framework mapping threats to cloud-hosted web apps and serverless platforms.

Microsoft introduced the cloud web applications threat matrix, which organizes attack techniques for cloud-hosted web apps and serverless platforms using MITRE ATT&CK tactics, from resource development through impact. The framework covers attack paths spanning application code, managed runtimes, workload identities, and deployment pipelines, cataloging techniques such as subdomain takeover, code injection in connected repositories, compromised registry images, exposed admin interfaces, and serverless trigger injection. It builds on Microsoft's earlier Kubernetes and storage services matrices to help defenders identify visibility gaps, prioritize hardening, and plan investigations in cloud-native environments.

Microsoft Security Blog · 6d agoTools

How to secure edge AI in customer-owned environments

Microsoft outlines security architecture guidance for edge AI, urging runtime attestation, artifact provenance, and deterministic mediation of model actions.

Microsoft details how edge AI shifts trust responsibilities to customers operating their own infrastructure, where prompt injection, model tampering, and malicious firmware updates can occur alongside model weights, credentials, and physical-system access. The guidance recommends verifying runtimes with attestation, verifying AI artifacts with provenance, and constraining model actions through a deterministic mediator outside the model. It also covers new exposure surfaces from MCP, multi-agent systems, and computer-use agents running in disconnected or hostile edge environments.

Microsoft Security Blog · 11d agoAI safety & security

ASCII smuggling crosses over from AI prompt injection to phishing evasion

Microsoft details high-volume phishing campaign using ASCII smuggling (Unicode tag chars) for filter evasion, peaking at 2.3M messages.

Microsoft researchers observed a high-volume finance-themed phishing campaign using invisible Unicode tag characters (U+E0000–U+E007F), a technique known from AI prompt injection research as ASCII smuggling, to split lure words like 'funding' and evade email filters. Telemetry from Microsoft Defender for Office 365 showed signature hits jump from roughly 21,000 messages on February 8, 2026 to more than 1.3 million on February 9, peaking above 2.3 million on February 11, with elevated weekday activity lasting approximately three months. The discovery emerged from prompt injection protection research, showing AI-era evasion techniques crossing into traditional phishing. Most messages were flagged by layered Defender protections rather than a single Unicode-specific signal.

Microsoft Security Blog · 12d agoPhishing & fraud in the wild

Impersonating IT support: how threat actors turn a remote session into enterprise-wide access

Microsoft details Teams IT-support impersonation campaigns deploying Node.js implants, AD reconnaissance, and WinRM lateral movement toward domain controllers.

Microsoft Threat Intelligence describes a human-operated campaign where attackers impersonate IT/helpdesk staff via Microsoft Teams external collaboration, talk users into granting remote sessions, and use RMM tools for interactive access. During the session they run PowerShell to silently install a malicious MSI that stages a portable Node.js runtime and obfuscated JavaScript implant for C2, executing follow-on payloads via rundll32. Operators then perform host and Active Directory reconnaissance, capture desktop screenshots, and pivot via WinRM on port 5985 to domain controllers and certificate authorities. The hands-on-keyboard chain, which can precede data theft and ransomware, blends into normal operations by relying on Teams, Quick Assist, msiexec, and Node.js; Microsoft shares hunting and mitigation guidance.

Microsoft Security Blog · 12d agoThreat actor in the wild

Counterfeit installers to system compromise: Tracking a deceptive software download campaign

Microsoft tracks a counterfeit software-installer campaign compromising multinationals' China operations, moderately linked to the Silver Fox (Yinhu) actor.

Microsoft Defender Experts is tracking an active campaign using spoofed software download sites for brands such as Razer, Kaspersky, Microsoft Edge, Calibre, and Baidu Netdisk on .com.cn and .hl.cn domains, delivering installer archives whose hashes change per download, indicating server-side payload generation. The implants establish persistence, weaken security protections, and communicate with attacker-controlled infrastructure, with confirmed compromises across healthcare, manufacturing, gaming, technology, logistics, government, and education. Microsoft assesses with moderate confidence that the activity matches the publicly reported Silver Fox (Yinhu) fake software campaign; it has not attributed it to a nation-state actor.

Microsoft Security Blog · 13d agoThreat actor in the wild1

Cybersecurity IR Workshop: The workshop you shouldn’t miss

Microsoft's DART team promotes a 2-3 day Cybersecurity Incident Response Readiness Workshop that stress-tests IR plans against simulated attacks.

Microsoft's Detection and Response Team (DART), which delivers Defender Experts incident response and has supported organizations across 54 countries, is offering its Cybersecurity Incident Response Readiness Workshop. The scenario-driven engagement exercises detection, investigation, containment, and decision-making across identity, endpoint, cloud, and communications, ending with prioritized recommendations. It is available to Unified Enterprise agreement customers via their Customer Success Account Manager.

Microsoft Security Blog · 14d agoIndustry

TerminalFix campaign deploys a reverse tunnel through multistage intrusion

Microsoft Threat Intelligence details the TerminalFix campaign, which uses fake CAPTCHA prompts, DLL sideloading, and reverse tunnels in multistage intrusions.

Microsoft Threat Intelligence published analysis of a ClickFix-style campaign dubbed TerminalFix. The intrusion chain relies on fake CAPTCHA social engineering and DLL sideloading, and the attackers deploy a reverse tunnel to maintain access through a multistage intrusion. Microsoft released detections and threat hunting guidance for defenders.

Microsoft Security Blog · 17d agoThreat actor in the wild

​​​​​​What’s new in Microsoft Security: August 2026

Microsoft's August 2026 security update roundup adds agent-activity insights, expanded environment coverage, and enhanced security management capabilities.

Microsoft published its monthly 'What's new in Microsoft Security' roundup for August 2026. The updates add capabilities for gaining insights into agent activity, expand security coverage across supported environments, and enhance security management across customer environments. No specific product names, CVEs, or incident details were included in the available text.

Microsoft Security Blog · 19d agoTools

When AI infrastructure becomes the target: Securing gateways and control points

Microsoft Threat Intelligence details attacks on exposed AI workloads exploiting LiteLLM gateways for credential harvesting, persistence, and cryptomining.

Microsoft Threat Intelligence examines attacks targeting exposed AI workloads, including exploitation of LiteLLM gateway deployments. Post-exploitation activity includes credential harvesting, establishing persistence, and cryptomining. The post urges defenders to secure AI infrastructure gateways and control points; the available text does not name threat actors, CVEs, or provide IOCs.

Microsoft Security Blog · 20d agoExploit / PoC in the wild

The patch window is collapsing: Why security needs a new control plane

Microsoft argues patch windows are shrinking and urges a new security control plane to protect systems between vulnerability discovery and remediation.

A Microsoft Security Blog post contends that the window between vulnerability discovery and patch deployment is collapsing, leaving exploitable gaps. It argues organizations need a security 'control plane' that provides protection in the gap between discovery and remediation. The piece is vendor thought leadership with no new incident, CVE, or product announcement details.

Microsoft Security Blog · 21d agoIndustry1

Microsoft named a Leader in the Frost Radar™: Cloud Workload Protection Platforms, 2026

Microsoft was named a leader in the 2026 Frost Radar for Cloud Workload Protection Platforms, cited for Defender for Cloud runtime security.

The 2026 Frost Radar for Cloud Workload Protection Platforms placed Microsoft in its leadership tier, calling the company a visionary leader. Microsoft attributes the recognition to unified runtime security delivered through Microsoft Defender for Cloud. The post is vendor marketing with no incident, vulnerability, or technical detail.

Microsoft Security Blog · 27d agoIndustry2