https://www.bleepingcomputer.com/news/microsoft/microsoft-solarwinds-hackers-downloaded-azure-exchange-source-code/

Microsoft announced today that the SolarWinds hackers could gain access to source code for a limited amount of components used by Azure, Intune, and Exchange.

In December, it was disclosed that the SolarWinds' network management company suffered a sophisticated cyberattack that allowed hackers to create a supply chain attack targeting the company's customers.