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Microsoft Threat Intelligence
@threatintel.microsoft.com
We are Microsoft's global network of security experts. Follow for security research and threat intelligence. https://aka.ms/threatintelblog
Most successful exploitation activity related to the CVE-2025-55182 vulnerability affecting React Server Components, Next.js, and related frameworks originated from red team assessments, but observed exploitation attempts by threat actors deliver various payloads. msft.it/63323tmKIh
Defending against the CVE-2025-55182 (React2Shell) vulnerability in React Server Components | Microsoft Security Blog
CVE-2025-55182 (also referred to as React2Shell and includes CVE-2025-66478, which was merged into it) is a critical pre-authentication remote code execution (RCE) vulnerability affecting React Server Components and related frameworks.
msft.it
December 15, 2025 at 7:45 PM
The December 2025 security updates are available:
Security updates for December 2025 are now available. Details are here: msft.it/6018SZEg0

#PatchTuesday #SecurityUpdateGuide
December 9, 2025 at 7:22 PM
"Defense is doable… We have to be brilliant at the basics... It’s about doing really good access management, really good principle of least privilege, really good network architecture..." -- Matt Duncan, E-ISAC VP of Security Operations and Intelligence msft.it/63325tdPsv
The Grid, a Digital Frontier: E-ISAC on Securing the Power Grid
In this episode of the Microsoft Threat Intelligence Podcast, host⁠ ⁠⁠⁠Sherrod DeGrippo⁠ is joined by Matt Duncan, Vice President of Security Operations and Intelligence at the North American Electric Reliability Corporation’s E-ISAC, to explore the cyber threats targeting the North American power grid. Matt breaks down why the grid remains resilient despite increasing pressure from nation-states, cybercriminals, and hacktivists, how AI is lowering the barrier of entry for attackers, and why OT systems and interconnected devices present unique risks. He also highlights real success stories, the value of large-scale grid exercises, and how strong collaboration and a focus on foundational security practices help defenders keep power flowing safely and reliably.
msft.it
December 3, 2025 at 5:47 PM
On Thanksgiving eve, November 26, Microsoft detected and blocked a high-volume phishing campaign from a threat actor we track as Storm-0900. The campaign used parking ticket and medical test result themes and referenced Thanksgiving to lend credibility and lower recipients’ suspicion.
December 2, 2025 at 12:22 AM
Throughout 2025, Tycoon2FA (tracked by Microsoft as Storm-1747) has consistently been the most prolific phishing-as-a-service (PhaaS) platform observed by Microsoft. In October 2025, Microsoft Defender for Office 365 blocked more than 13 million malicious emails linked to Tycoon2FA.
November 21, 2025 at 5:23 PM
The Threat Intelligence Briefing Agent, which delivers daily briefings that combine Microsoft’s global threat intelligence with insights specific to each organization, is now fully integrated into the Microsoft Defender portal, available in public preview. msft.it/63329trKYc
November 18, 2025 at 11:22 PM
Microsoft is introducing a dozen new and enhanced Microsoft Security Copilot agents in Microsoft Defender, Microsoft Entra, Microsoft Intune, & Microsoft Purview. Our partner community also released more than 30 new Security Copilot agents. msft.it/63323tR70T
Agents built into your workflow: Get Security Copilot with Microsoft 365 E5 | Microsoft Security Blog
At Microsoft Ignite 2025, we are not just announcing new features—we are redefining what’s possible, empowering security teams to shift from reactive responses to proactive strategies.
msft.it
November 18, 2025 at 6:17 PM
The November 2025 security updates are available:
Security updates for November 2025 are now available! Details are here: msft.it/6018SZEg0

#PatchTuesday #SecurityUpdateGuide
November 11, 2025 at 6:16 PM
Microsoft has discovered a new type of side-channel attack on remote language models. This type of side-channel attack could allow an attacker in a position to observe network traffic to conclude language model conversation topics, despite end-to-end encryption. msft.it/63328tJAeu
​​Whisper Leak: A novel side-channel attack on remote language models | Microsoft Security Blog
Understand the risks of encrypted AI traffic exposure and explore practical steps users and cloud providers can take to stay secure. Learn more.
msft.it
November 7, 2025 at 7:49 PM
Dive into the heart of threat intelligence as Principal Security Researcher Jonathan Bar Or reveals how proactive security research powers Microsoft’s defenses. msft.it/63325tJxpx
November 7, 2025 at 4:45 PM
In the latest Microsoft Threat Intelligence Podcast episode, Sherrod DeGrippo and Zack Korman explore the future risks and opportunities that AI introduces in cybersecurity, cutting through hype to discuss where AI is both brilliant and flawed: msft.it/63329tyToL
Beyond AI for Security Hype: What Really Matters in Cyber Defense
In this episode of the Microsoft Threat Intelligence Podcast, host⁠ ⁠⁠⁠Sherrod DeGrippo⁠ is joined by ⁠Zack Korman⁠, CTO of cybersecurity startup Pistachio. They explore the reality of AI in security, cutting through hype to discuss where AI is both brilliant and flawed, how vendors AI-wash outdated tech, and why Zack believes AI won’t replace jobs but instead scale human creativity. They also dive into phishing simulations, human psychology behind social engineering, AI-powered attacks, jailbreak chaining between AI systems, and the future risks and opportunities AI introduces in cybersecurity.
msft.it
November 5, 2025 at 7:16 PM
Microsoft Incident Response – Detection and Response Team (DART) uncovered SesameOp, a new backdoor that uses the OpenAI Assistants API for command and control. DART shared the findings with OpenAI, who identified and disabled an API key and associated account. msft.it/63322tGbej
SesameOp: Novel backdoor uses OpenAI Assistants API for command and control | Microsoft Security Blog
Microsoft Incident Response - Detection and Response Team (DART) researchers uncovered a new backdoor that is notable for its novel use of the OpenAI Assistants Application Programming Interface (API) as a mechanism for command-and-control (C2) communications. Instead of relying on more traditional methods, the threat actor behind this backdoor abuses OpenAI as a C2 channel as a way to stealthily communicate and orchestrate malicious activities within the compromised environment. To do this, a component of the backdoor uses the OpenAI Assistants API as a storage or relay mechanism to fetch commands and run tasks for the threat actor.
msft.it
November 3, 2025 at 5:26 PM
MapUrlToZone (MUTZ) drives several security decisions across Windows. This @msrc.microsoft.com blog sets out to understand MUTZ and its behavior more deeply, identify issues, and propose solutions to strengthen MUTZ against future bypasses:
Ever wondered how Windows decides if a file path is local, intranet, or Internet, and why it matters for security? MSRC security researchers dive deep into MapUrlToZone (MUTZ).

Learn more in our blog post: www.microsoft.com/en-us/msrc/b...
October 30, 2025 at 5:52 PM
Microsoft’s threat hunters are transforming cyber defense by seeking out emerging threats before they strike. Instead of waiting for alerts, these experts combine human intuition with AI-powered analysis to uncover malicious activity that others miss. msft.it/63321tBQRR
October 27, 2025 at 5:00 PM
"Threats are accelerating, yet our defensive capabilities have never been stronger. The gap is not technology. The gap is in how we think about and operationalize security." -- Microsoft CVP and Deputy CISO @ajohnsocyber.bsky.social on the evolved CISO mandate. msft.it/63328sh6s6
The CISO imperative: Building resilience in an era of accelerated cyberthreats | Microsoft Security Blog
Security is no longer just tech-it's strategy. See how CISOs are leading resilient organizations. Learn more.
msft.it
October 22, 2025 at 10:35 PM
This year’s Microsoft Digital Defense Report spotlights the rise of industrialized cybercrime and the increasing complexity of attacks, as adversaries pivot from traditional email-based threats to platforms like Teams, SMS, and WhatsApp. msft.it/63329sCxgf
The New Frontlines of Cybersecurity: Lessons from the 2025 Digital Defense Report
In this episode of the Microsoft Threat Intelligence Podcast, host Sherrod DeGrippo is joined by Chloé Messdaghi and Crane Hassold to unpack the key findings of the 2025 Microsoft Digital Defense Report; a comprehensive look at how the cyber threat landscape is accelerating through AI, automation, and industrialized criminal networks. They explore how nation-state operations and cybercrime have fused into a continuous cycle of attack and adaptation, with actors sharing tooling, infrastructure, and even business models. The conversation also examines AI’s growing impact, from deepfakes and influence operations to the defensive promise of AI-powered detection, and how identity compromise has become the front door to most intrusions, accounting for over 99% of observed attacks.
msft.it
October 22, 2025 at 5:00 PM
Azure Blob Storage is a high-value target for threat actors due to its critical role in storing and managing massive amounts of unstructured data at scale across diverse workloads: msft.it/63324s7pFk
Inside the attack chain: Threat activity targeting Azure Blob Storage | Microsoft Security Blog
Azure Blob Storage is a high-value target for threat actors due to its critical role in storing and managing massive amounts of unstructured data at scale across diverse workloads and is increasingly targeted through sophisticated attack chains that exploit misconfigurations, exposed credentials, and evolving cloud tactics.
msft.it
October 20, 2025 at 4:08 PM
The Microsoft Digital Defense Report 2025 shows how threats are evolving faster than ever, fueled by AI. msft.it/63322sf3y4

Key insights from report include:

- More than 50% of cyberattacks with known motives had financial objectives such as extortion or ransom.
Extortion and ransomware drive over half of cyberattacks
Microsoft launches its sixth annual Digital Defense Report, highlighting trends from July 2024 to June 2025, including that over half of cyberattacks with known motives were driven by extortion or ransomware. The report stresses that legacy security is insufficient—modern AI-driven defenses and cross-industry collaboration are essential. For individuals, strong tools like phishing-resistant MFA can block over 99% of identity-based attacks.
msft.it
October 16, 2025 at 2:54 PM
In early October 2025, Microsoft disrupted a Vanilla Tempest campaign by revoking over 200 certificates that the threat actor had fraudulently signed and used in fake Teams setup files to deliver the Oyster backdoor and ultimately deploy Rhysida ransomware.
October 15, 2025 at 10:46 PM
The October 2025 security updates are available: msft.it/6018SZEg0.

#PatchTuesday #SecurityUpdateGuide
October 14, 2025 at 5:16 PM
“Security begins and ends with people.” Learn how Microsoft has made security culture a company-wide imperative, reinforcing vigilance, embedding secure habits into everyday work, and achieving what technology alone cannot, via @ajohnsocyber.bsky.social: msft.it/63325sNpfJ
How Microsoft is creating a security-first culture that lasts | Microsoft Security Blog
Discover how Microsoft empowers employees to lead with security through training, tools, and a company-wide mindset shift. Learn more.
msft.it
October 13, 2025 at 5:45 PM
Microsoft Threat Intelligence has observed a financially motivated threat actor, Storm-2657, compromising employee accounts to gain unauthorized access to profiles and divert salary payments to attacker-controlled accounts. msft.it/63320sFB5j
Investigating targeted "payroll pirate" attacks affecting US universities | Microsoft Security Blog
Microsoft Threat Intelligence has identified 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, attacks that have been dubbed "payroll pirate".
msft.it
October 9, 2025 at 3:21 PM