The Senate will hold a hearing Tuesday investigating the SolarWinds hacks. SolarWinds is a massive IT company that contracted with the federal government. Its ubiquity let hackers get into at least nine federal agencies, including the departments of — just to pick three of the scariest options — Defense, Homeland Security and Treasury. The breach is what’s known as a supply chain hack. They’re increasingly common because it’s hard for companies and governments to verify the security of every company they work with. But experts say it’s time to create disincentives for not doing that homework. Molly spoke with Camille Stewart, a cyber-fellow at Harvard’s Belfer Center.