The massive SolarWinds hack that affected several US government agencies and cybersecurity vendors was “the largest and most sophisticated attack the world has ever seen,” Microsoft President Brad Smith said during an interview on the CBS program 60 Minutes.

Smith also revealed that Microsoft had assigned 500 engineers to investigate the months-long hacking campaign.

Microsoft said in January that the nation state group behind the SolarWinds cyberattack managed to view source code repositories for some of the company’s products.

The tech giant said it detected malicious SolarWinds applications in its environment, which the company isolated and removed.

Moreover, the Cyber Unified Coordination Group (UCG) earlier alleged that the hack was “likely Russian in origin”.

The group, composed of the FBI, CISA, and ODNI with support from NSA, said that an Advanced Persistent Threat (APT) actor is responsible for most or all of the recently discovered, ongoing cyber compromises of both government and non-governmental networks.