Microsoft was hacked as part of the suspected Russian campaign that has hit multiple US government agencies, people familiar with the matter told Reuters on Thursday.
According to the report, the hackers took advantage of the widespread use of software from SolarWinds Corp. Microsoft’s own products were then used to further the attacks on others, the people said.
Microsoft said it had detected a malicious version of software from SolarWinds inside the company but added that its investigation so far showed no evidence hackers had used Microsoft systems to attack customers.
Earlier on Thursday, officials said that the Energy Department and National Nuclear Security Administration, which maintains the US nuclear weapons stockpile, were targeted as part of the massive hacking attack.
On Wednesday, the US government confirmed that a cyberattack affected its networks and said the attack was "significant and ongoing".
The confirmation came days after it was reported that a group of hackers backed by a “foreign government” stole information from the US Treasury Department and the Commerce Department’s National Telecommunications and Information Administration (NTIA).
Subsequently it was revealed that the attack also targeted the US Department of Homeland Security.