One of the hacked organizations reportedly includes the U.S. agency responsible for maintaining the country's stockpile of nuclear weapons. China-backed hackers have been observed carrying out the hacks targeting SharePoint servers.

Microsoft Corp. issued a progress report on what it described as the largest cybersecurity engineering project in history.

The US government agency in charge of designing and maintaining nuclear weapons was among those breached by a hack of Microsoft's SharePoint server software, Bloomberg reported. However, attackers weren't able to obtain any sensitive or classified information,