A security patch Microsoft released this month failed to fully fix a critical flaw in the U.S. tech giant's SharePoint server software, opening the door to a sweeping global cyber espionage effort, a timeline reviewed by Reuters shows.

If exploited, attackers can gain full access to SharePoint content and potentially pivot to Outlook, Teams, and OneDrive. Learn how to protect your SharePoint server from compromise.

At least 54 organizations have been breached in the attacks. Some of the attacks that targeted organizations using an exploit in Microsoft’s SharePoint server platform over the last few days have been linked to hacking groups affiliated with the Chinese government, according to a new Microsoft security blog.