THE DAY AFTER — Cybersecurity experts on Wednesday continued to analyze the Ransomware virus that spread around the world on Tuesday. The worm, like its predecessor WannaCry, relied in part on a Windows flaw exposed in a leak of alleged NSA hacking tools. But Microsoft and multiple security firms, including Kaspersky and Symantec, have now concluded that the outbreak began when unknown hackers compromised the software update process of a Ukrainian tax program, called MeDoc. “Microsoft now has evidence that a few active infections of the ransomware initially started from the legitimate MEDoc updater process,” the company said in a blog post, referring to the tax software. Microsoft’s analysis...