Microsoft is investigating a potential leak within its MAPP program, suspecting that Chinese state-backed hackers exploited SharePoint vulnerabilities before patches were widely available. The security flaw,

In a blog post Tuesday, Microsoft said it observed hackers attempting to “gain initial access to target organizations.” According to Microsoft, those involved included hacking groups called Linen Typhoon and Violet Typhoon—which Microsoft said are linked to the Chinese government—and China-based group Storm-2603.