Microsoft has relied on engineers based in China for years to help maintain some of the U.S. Department of Defense’s (DOD) most sensitive cloud computing systems, potentially leaving them vulnerable to hacking, according to a new investigation from ProPublica released Tuesday. Because U.S. law prohibits foreign nationals from directly accessing federal systems that handle sensitive data, Microsoft has been funneling work through American “digital escorts” — low-paid workers with security clearances but often possessing limited technical expertise — who input commands from more skilled China-based engineers into federal networks, according to ProPublica. The arrangement, largely unknown even within the federal...