SolarWinds, Microsoft, FireEye, CrowdStrike defend actions in major hack - U.S. Senate hearing

FILE PHOTO: A Microsoft logo is seen in Los Angeles, California U.S. November 7, 2017. REUTERS/Lucy Nicholson

WASHINGTON (Reuters) - Top executives at Texas-based software company SolarWinds Corp, Microsoft Corp and cybersecurity firms FireEye Inc and CrowdStrike Holdings Inc defended their conduct in breaches blamed on Russian hackers and sought to shift responsibility elsewhere in testimony to a U.S. Senate panel on Tuesday.

One of the worst hacks yet discovered had an impact on all four. SolarWinds and Microsoft programs were used to attack others and the hack struck at about 100 U.S. companies and nine federal agencies.