The suspected Russian hackers behind the worst U.S. cyberattack in years used reseller access to Microsoft Corp. services to penetrate targets that had no compromised network software from SolarWinds Corp., investigators said.Updates to SolarWinds’ Orion software were the only known point of entry until Thursday, when security company CrowdStrike Holdings Inc. said hackers had gained access to the vendor that sold it Office licenses and had used that to try to read CrowdStrike’s email. It did not specifically identify the hackers as being the ones that compromised SolarWinds, but two people …

The U.S. cybersecurity agency said on Wednesday that a sprawling cyber espionage campaign made public earlier this month is affecting state and local governments, although it released few additional details.The hacking campaign, which used U.S. tech company SolarWinds as a springboard to penetrate federal government networks, was “impacting enterprise networks across federal, state, and local governments, as well as critical infrastructure entities and other private sector organizations,” the Cybersecurity and Infrastructure Security Agency (CISA) said in a statement posted to its website.The CISA said last week that U.S. government agencies, …