[wkat4242]

I think you mean a magic bullet instead of a smoking gun :)

[bArray]

I meant "smoking gun" from a cyber security perspective, i.e. the conclusion or the final part of the investigation. "magic bullet" would also work here too though.

[MaKey]

Evidence, particularly of a crime, that is difficult or impossible to dispute. [1]

Even with your explanation I don't think it fits here.

[1] https://en.m.wiktionary.org/wiki/smoking_gun

[nmstoker]

You seem to have inferred the wrong meaning of "smoking gun" and that's why your usage above doesn't make sense.

There's no valid reason cyber security people would take a well known idiom and repurpose it as you imply, and a quick Google suggests they haven't done this.

[rzzzt]

Fish in a barrel!