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Microsoft server hack hit about 100 organizations, researchers say

Published by Global Banking & Finance Review

Posted on July 21, 2025

3 min read

· Last updated: January 22, 2026

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Microsoft server hack hit about 100 organizations, researchers say
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By James Pearson and Raphael Satter WASHINGTON/LONDON (Reuters) -A sweeping cyber espionage operation targeting Microsoft server software compromised about 100 different organizations as of the

Cyber Espionage Targets Microsoft Servers, Affecting Around 100 Organizations

By James Pearson and Raphael Satter

WASHINGTON/LONDON (Reuters) - A sweeping cyber espionage operation targeting Microsoft server software compromised about 100 different organizations as of the weekend, two of the organizations that helped uncover the campaign said on Monday.

Microsoft on Saturday issued an alert about "active attacks" on self-hosted SharePoint servers, which are widely used by organizations to share documents and collaborate within organisations. SharePoint instances run off of Microsoft servers were unaffected.

Dubbed a "zero-day" because it leverages a previously undisclosed digital weakness, the hacks allow spies to penetrate vulnerable servers and potentially drop a backdoor to secure continuous access to victim organizations.

Vaisha Bernard, the chief hacker at Eye Security, a Netherlands-based cybersecurity firm, which discovered the hacking campaign targeting one of its clients on Friday, said that an internet scan carried out with the Shadowserver Foundation had uncovered nearly 100 victims altogether - and that was before the technique behind the hack was widely known.

"It's unambiguous," Bernard said. "Who knows what other adversaries have done since to place other backdoors."

He declined to identify the affected organizations, saying that the relevant national authorities had been notified.

The Shadowserver Foundation confirmed the 100 figure and said that most of those affected were in the United States and Germany and that the victims included government organizations.

Another researcher said that, so far, the spying appeared to be the work of a single hacker or set of hackers.    

"It's possible that this will quickly change," said Rafe Pilling, director of Threat Intelligence at Sophos, a British cybersecurity firm.

Microsoft said it had "provided security updates and encourages customers to install them," a company spokesperson said in an emailed statement.

It was not clear who was behind the ongoing hack. The FBI said on Sunday it was aware of the attacks and was working closely with its federal and private-sector partners, but offered no other details. Britain's National Cyber Security Center said in a statement that it was aware of "a limited number" of targets in the United Kingdom. A researcher tracking the campaign said that the campaign appeared initially aimed at a narrow set of government-related organizations.

The pool of potential targets remains vast. According to data from Shodan, a search engine that helps to identify internet-linked equipment, over 8,000 servers online could theoretically have already been compromised by hackers.

Those servers include major industrial firms, banks, auditors, healthcare companies, and several U.S. state-level and international government entities. 

"The SharePoint incident appears to have created a broad level of compromise across a range of servers globally," said Daniel Card of British cybersecurity consultancy, PwnDefend. 

"Taking an assumed breach approach is wise, and it's also important to understand that just applying the patch isn't all that is required here."

(Reporting by James Pearson and Raphael Satter, Editing by Nick Zieminski and Marguerita Choy)

Key Takeaways

  • Cyber espionage operation targets Microsoft servers.
  • Around 100 organizations affected by the hack.
  • Hack leverages a zero-day vulnerability in SharePoint.
  • Most victims are in the US and Germany.
  • Microsoft has issued security updates to mitigate the threat.

Frequently Asked Questions

What organizations were affected by the Microsoft server hack?
About 100 different organizations were compromised, including government entities, primarily in the United States and Germany.
What type of vulnerability was exploited in the attack?
The attack utilized a 'zero-day' exploit, which takes advantage of a previously undisclosed digital weakness in Microsoft server software.
What actions has Microsoft taken in response to the hack?
Microsoft has issued security updates and is encouraging customers to install them to protect against the ongoing attacks.
Who is investigating the cyber attacks?
The FBI is aware of the attacks and is working closely with federal and private-sector partners to investigate the situation.
What is the potential scale of the threat posed by this hack?
There are over 8,000 servers online that could potentially be vulnerable, indicating a vast pool of possible targets for cyber espionage.

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