Comment by hedora

Usually, when intentional backdoors like that get found and fixed, the 'someone else' stays silent. Otherwise, they provide proof that they've been planting backdoors, and that's much worse than having a hole plugged.

To get an idea of how this stuff usually works, start with the Simple Sabotage field manual:

https://ia601309.us.archive.org/14/items/Simplesabotage/Simp...