> Given how easy the infiltration is and how extremely hard to detect it is, likely a lot.
This particular case seems to be an example of the exact opposite. It took "Jia Tan" two years to conduct all of the social engineering necessary to get into a position to introduce the backdoor, then upon doing so, was caught almost immediately, with the initial discovery not even coming from a dedicated security researcher, but from a sysadmin who kept digging when he saw unusual performance issues.
And the threat actor here deliberately went after the weakest link in the chain. Assuming that the goal was to compromise sshd, the antagonist evidently found it too much of a challenge to attempt to infiltrate OpenSSH itself, so targeted a small-team compression project that only some deployments even link to, and still got caught extremely rapidly.
This particular case seems to be an example of the exact opposite. It took "Jia Tan" two years to conduct all of the social engineering necessary to get into a position to introduce the backdoor, then upon doing so, was caught almost immediately, with the initial discovery not even coming from a dedicated security researcher, but from a sysadmin who kept digging when he saw unusual performance issues.
And the threat actor here deliberately went after the weakest link in the chain. Assuming that the goal was to compromise sshd, the antagonist evidently found it too much of a challenge to attempt to infiltrate OpenSSH itself, so targeted a small-team compression project that only some deployments even link to, and still got caught extremely rapidly.