China-Linked Hackers Backdoored Linux Login Software to Hide for Nearly a Decade

Instead of hiding on the laptops and servers defenders watch most closely, a China-nexus group spent close to a decade hidden inside the Linux login system itself. Sygnia, which tracks the group as Velvet Ant, says it backdoored the PAM and OpenSSH components that decide who is allowed to sign in, planting its access where ordinary cleanup could not reach it.