Investigators probing a massive hack of the U.S. government and businesses say they have found concrete evidence the suspected Russian espionage operation went far beyond the compromise of the small software vendor publicly linked to the attack. From a report: Close to a third of the victims didn’t run the SolarWinds software initially considered the main avenue of attack for the hackers, according to investigators and the government agency digging into the incident. The revelation is fueling concern that the episode exploited vulnerabilities in business software used daily by millions [Editor’s note: the link may be paywalled; alternative source]. Hackers linked to the attack have broken into these systems by exploiting known bugs in software products, by guessing online passwords and by capitalizing on a variety of issues in the way Microsoft cloud-based software is configured, investigators said. Approximately 30% of both the private-sector and government victims linked to the campaign had no direct connection to SolarWinds, Brandon Wales, acting director of the Cybersecurity and Infrastructure Security Agency, said in an interview. The attackers “gained access to their targets in a variety of ways. This adversary has been creative,” said Mr. Wales, whose agency, part of the U.S. Department of Homeland Security, is coordinating the government response. “It is absolutely correct that this campaign should not be thought of as the SolarWinds campaign.” Corporate investigators are reaching the same conclusion. Last week, computer security company Malwarebytes said that a number of its Microsoft cloud email accounts were compromised by the same attackers who targeted SolarWinds, using what Malwarebytes called “another intrusion vector.”Read more of this story at Slashdot.