Mark Warner Cyber Attack

The unprecedented cyber attack on U.S. government agencies reported this month may have started earlier than last spring, according to a U.S. senator involved in cybersecurity.

Democrat Mark Warner, vice-chair of the Senate Intelligence Committee, said on Wednesday that the attack was only made public earlier this month.

It had used the U.S. tech company SolarWinds as a springboard to penetrate government networks, as well as critical infrastructure entities and private companies, for months.