It is likely the professor involved here will be fired if they are pre-tenure, or sanctioned if post-tensure.
Of course, there are other ethical and legal requirements that you're bound to, not just this one. I'm not sure which requirements IRBs in the US look into though, it's a pretty murky situation.
It seems to qualify per §46.102(e)(1)(i) ("Human subject means a living individual about whom an investigator [..] conducting research: (i) Obtains information [...] through [...] interaction with the individual, and uses, studies, or analyzes the information [...]")
I don't think it'd qualify for any of the exemptions in 46.104(d): 1 requires an educational setting, 2 requires standard tests, 3 requires pre-consent and interactions must be "benign", 4 is only about the use of PII with no interactions, 5 is only about public programs, 6 is only about food, 7 is about storing PII and not applicable and 8 requires "broad" pre-consent and documentation of a waiver.
I had a look at section §46.104 https://www.hhs.gov/ohrp/regulations-and-policy/regulations/... since it mentioned exemptions, and at (d) (3) inside that. It still doesn't apply: there's no agreement to participate, it's not benign, it's not anonymous.
IRBs are like the TSA. Imposing annoyance and red tape on the honest vast-majority while failing to actually filter the 0.0001% of things they ostensibly exist to filter.
I'm guessing it passed for similar reasoning, along with the reviewers being unfamiliar with how "vulnerabilities are injected." To get the bad code in, the researcher needed to have the code reviewed by a human.
So if you rephrase "inject vulnerability" as "sneak my way past a human checkpoint", you might have a better idea of what they were actually doing, and might be better equipped to judge its ethical merit -- and if it qualifies as research on human subjects.
To my thinking, it is quite clearly human experimentation, even if the subject is the process rather than a human individual. Ultimately, the process must be performed by a human, and it doesn't make sense to me that you would distinguish between the two.
And the maintainers themselves express feeling that they were the subject of the research, so there's that.
Main point is that IRBs were created in response to some highly unethical and harmful "studies" being carried out by institutions thought of as top-tier. Now they are considered to be a mandatory part of carrying out ethical research. But if you think about it, isn't outsourcing all sense of ethics to an organization external to the actual researchers kind of the opposite of what we want to do?
All institutions tend to be corruptible. Many tend to respond to their actual incentives rather than high-minded statements about what they're supposed to be about. Seems to me that promoting the attitude of "well an IRB approved it, so it must be all right, let's go!" is the exact opposite of what we really want.
All things considered, it's probably better to have something there than nothing. But you still have to be responsible for your own decisions. I bamboozled our lazy IRB into approving our study, so I'm not responsible for it being obviously a bad idea, just isn't good enough.
If you think about it, it's actually kind of meta to the code review process they were "studying". Just like IRBs, Code review is good, but no code review process will ever be good enough to stop every malicious actor every time. It will always be necessary to track the reputation of contributors and be able to mass-revert contributions from contributors later determined to be actively malicious.
Eventually, the IRB, unhappy at his behavior, said he couldn't do the experiment. He left for another institution (UC San Diego) immediately, having made a deal with the new dean to go through expedited review. It was a big loss for Boulder and TBH, the IRB's reasoning was not sound.