FireEye said in a blog post that its investigation into the hack of its own network had identified 'a global campaign' targeting governments and the private sector that, beginning in the spring, slipped malware into a SolarWinds software update.
The malware gave the hackers remote access to victims' networks.
FireEye said it had notified 'multiple organisations' globally where it saw indications of compromise.
The US government did not publicly identify Russia as the culprit behind the hacks, first reported by Reuters, and said little about who might be responsible.
https://www.dailymail.co.uk/news/article-9051211/GCHQ-spies-probe-hackers-stole-UK-government-secrets-cyber-attack-agencies.html