The attack was on several versions of Microsoft's SharePoint software that serve as a document storage platform for customers who don’t want to use the cloud. Microsoft released patches for a pair of SharePoint bugs earlier this month, but the quick fixes were easily bypassed, allowing China-linked hackers to break into hundreds of organizations. Microsoft quickly reacted by releasing its new fixes for the bugs within 72 hours of discovering the attack, reaching out to customers, and publishing two blog posts on the issue.