Higher education has long been a target of ransomware gangs and data extortion attacks. But never before, perhaps, has a cyberattack against a single software platform so thoroughly disrupted the daily operations of thousands of schools across the United States. The widely used digital learning platform Canvas was put into “maintenance mode” on Thursday after its maker, the education tech giant Instructure, suffered a data breach and faced an extortion attempt by attackers using the recognizable moniker "ShinyHunters." Though the hackers have been advertising the breach and attempting to extract a ransom payment from Instructure since May 1, the situation took on additional immediacy for regular people across the US and beyond on Thursday because the Canvas downtime caused chaos at schools, including those in the midst of finals and end-of-year assignments.…