What's happened
Since early July 2025, hackers exploiting a zero-day vulnerability in Microsoft’s on-premises SharePoint servers have breached hundreds of organizations worldwide, including US federal agencies like the National Nuclear Security Administration. The flaw, CVE-2025-53770, allows remote code execution and theft of authentication keys. Microsoft has released patches, but experts warn many systems remain compromised.
What's behind the headline?
Depth of the Breach and Technical Sophistication
The SharePoint vulnerability (CVE-2025-53770) represents a severe security failure due to its ability to grant unauthenticated remote code execution and theft of cryptographic keys. This allows attackers to impersonate legitimate users and maintain persistent access even after patches are applied. The exploitation chain involves advanced techniques such as deserialization attacks and extraction of machine keys from memory, demonstrating high technical sophistication.
Geopolitical and Security Implications
The involvement of China-backed hacking groups like Linen Typhoon, Violet Typhoon, and Storm-2603 highlights ongoing cyber espionage campaigns targeting government and critical infrastructure globally. The breach of the National Nuclear Security Administration underscores the potential national security risks.
Challenges in Mitigation and Recovery
Despite Microsoft’s rapid patch deployment, the nature of the attack means that simply applying updates is insufficient. Organizations must rotate cryptographic keys and assume compromise, complicating recovery efforts. The widespread use of SharePoint across sectors increases the attack surface, making comprehensive remediation a massive undertaking.
Broader Impact and Future Risks
The vulnerability’s deep integration with Microsoft’s ecosystem—including Teams, OneDrive, and Outlook—means that compromised SharePoint servers can lead to broader network intrusions and data theft. The attack serves as a warning about the risks of self-hosted enterprise software and the need for robust cybersecurity hygiene.
Forecast
This incident will likely prompt increased scrutiny of on-premises software vulnerabilities and accelerate migration to cloud-based solutions with stronger security controls. Governments and enterprises will need to invest heavily in detection, response, and prevention to mitigate similar future threats.
What the papers say
Ariel Zilber of the New York Post details the scale of the breach, noting that "around 400 government agencies in the US, Mauritius, Jordan, South Africa and the Netherlands were impacted," with the National Nuclear Security Administration among the targets. Zilber highlights that "no sensitive or classified information was known to have been stolen," but the attack exploited a Microsoft SharePoint zero-day vulnerability allowing hackers to steal authentication keys and impersonate users.
TechCrunch provides technical context, explaining that the vulnerability "allows an attacker to remotely run malicious code on the affected server," and that "several China-backed hacking groups are exploiting the bug," including Linen Typhoon and Violet Typhoon. They emphasize the zero-day nature of the exploit and Microsoft's ongoing patch efforts.
Dan Goodin at Ars Technica offers a deep dive into the technical mechanics, describing how attackers use a webshell-based backdoor called ToolShell to extract the ValidationKey from memory, enabling remote code execution. He notes the severity rating of 9.8 out of 10 and warns that "anyone running an on-premises instance of SharePoint should assume their networks are breached."
Al Jazeera and Gulf News report on the global scope and government responses, with Al Jazeera quoting Eye Security's Vaisha Bernard saying, "Who knows what other adversaries have done since to place other backdoors," and Gulf News noting that the FBI and CISA are coordinating responses and mandating fixes for federal agencies.
The Independent and AP News echo Microsoft’s patch releases and CISA’s warnings, emphasizing the risk to connected services like OneDrive and Teams and recommending immediate disconnection of vulnerable servers until patched.
Together, these sources paint a comprehensive picture of a widespread, sophisticated cyberattack exploiting a critical SharePoint vulnerability, with significant implications for government and private sector cybersecurity.
How we got here
Microsoft SharePoint is widely used by organizations to store and share internal documents. In July 2025, a critical zero-day vulnerability was discovered in self-hosted SharePoint servers, enabling hackers to remotely execute code and steal sensitive data. The flaw was exploited by China-backed groups and others, prompting urgent patches and warnings from cybersecurity agencies.
Go deeper
- How did hackers exploit the SharePoint vulnerability?
- Which organizations were most affected by the breach?
- What steps should companies take to protect themselves now?
Common question
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What Is the SharePoint Zero-Day Vulnerability and How Does It Affect Organizations?
A critical zero-day vulnerability has been discovered in on-premises SharePoint servers, exploited by hackers to breach systems worldwide. This flaw, identified as CVE-2025-53770, has led to active compromises, including data theft and remote code execution. Organizations using SharePoint on-premises need to act fast to patch their systems and prevent further damage. Below, we answer key questions about this vulnerability, how it impacts security, and what steps to take next.
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What Does the Athens Shooting Reveal About International Safety Concerns?
The recent shooting of a UC Berkeley professor in Athens has raised serious questions about personal safety and international security. Incidents like this highlight the risks faced by foreigners abroad, especially in regions with ongoing legal and personal conflicts. As global tensions rise, many are wondering how safe they really are when traveling or living overseas. Below, we explore the implications of this event and what it means for international safety today.
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How Do Zero-Day Vulnerabilities Like the SharePoint Flaw Impact Businesses?
Recent security breaches, such as the critical SharePoint vulnerability exploited by hackers, highlight the serious risks zero-day flaws pose to organizations. These vulnerabilities can lead to data breaches, system compromises, and significant operational disruptions. Understanding how these flaws affect businesses and what steps to take can help organizations stay protected. Below, we explore common questions about zero-day vulnerabilities and cybersecurity best practices in 2025.
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What is the SharePoint zero-day vulnerability CVE-2025-53770?
A critical zero-day vulnerability in on-premises SharePoint servers, CVE-2025-53770, has been actively exploited since July 7, affecting organizations worldwide. Despite patches from Microsoft, many systems remain vulnerable, leading to data theft and remote code execution risks. Curious about what this means for your organization? Below, we answer key questions about this serious cybersecurity threat and how to stay protected.
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Cybersecurity in 2025: Major Threats and How to Stay Safe
Cybersecurity threats are evolving rapidly in 2025, with new vulnerabilities and attack methods emerging worldwide. From zero-day exploits in popular platforms like SharePoint to sophisticated hacking campaigns backed by nation-states, understanding the current landscape is crucial. This page explores the biggest threats facing individuals and organizations today, along with practical tips to protect your data and systems. Curious about how to defend against these threats? Keep reading for expert insights and actionable advice.
More on these topics
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Microsoft Corporation is an American multinational technology company with headquarters in Redmond, Washington. It develops, manufactures, licenses, supports, and sells computer software, consumer electronics, personal computers, and related services.
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SharePoint is a web-based collaborative platform that integrates with Microsoft Office. Launched in 2001, SharePoint is primarily sold as a document management and storage system, but the product is highly configurable and its usage varies substantially a
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The Cybersecurity and Infrastructure Security Agency was established on 16 November 2018 when President Donald Trump signed into law the Cybersecurity and Infrastructure Security Agency Act of 2018.
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CISA or Cisa may refer to:
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The Federal Bureau of Investigation is the domestic intelligence and security service of the United States and its principal federal law enforcement agency.
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Google LLC is an American multinational technology company that specializes in Internet-related services and products, which include online advertising technologies, a search engine, cloud computing, software, and hardware.
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The National Nuclear Security Administration is a United States federal agency responsible for safeguarding national security through the military application of nuclear science.