There's always Ken Thompson's hack of the compiler to insert a backdoor into the...

		gpvos on Sept 25, 2020 \| parent \| context \| favorite \| on: Windows XP source code has leaked There's always Ken Thompson's hack of the compiler to insert a backdoor into the login program on Unix. See Reflections on Trusting Trust: https://www.win.tue.nl/~aeb/linux/hh/thompson/trust.html .