The hackers behind the initial wave of attacks exploiting a zero-day in Microsoft SharePoint servers have so far primarily targeted government organizations, according to researchers as well as news reports.

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 organisations.

A major cyberespionage operation targeting Microsoft's SharePoint server software has compromised about 100 organizations worldwide. The operation exploits a zero-day vulnerability, allowing hackers to install backdoors on affected servers.

A major cyber espionage campaign exploiting a previously unknown vulnerability in Microsoft’s self-hosted SharePoint software has compromised nearly 100 organizations, according to cybersecurity firms Eye Security and the Shadowserver Foundation.

Hackers exploited a security flaw in common Microsoft Corp. software to breach governments, businesses and other organizations across the globe and steal sensitive information, according to officials and cybersecurity researchers.