They might not even use blackmail, they might just "help out" in a difficult financial situation. Some people are in severe debt, have a gambling problem, are addicted to expensive drugs, or might need a lot of money for a sick relative. There are many possibilities.
The trick is finding the people that can be compromised.
I think you're going overboard on what's required. Take anybody who is simultaneously offered a substantial monetary incentive (let's say 4 years of total current/vesting comp), and also threatened with the release of something that we'll say is little more than moderately embarrassing. And this dev is being asked to do something that stands basically 0 risks of consequences/exposure for himself due to plausible deniability.
For instance, this is the heartbleed bug: "memcpy(bp, pl, payload);". You're copying (horrible naming conventions) payload bytes from pl to bp, without ensuring that the size of pl is >= payload, so an attacker can trivially get random bytes from memory. Somehow nobody caught one of the most blatant overflow vulnerabilities, even though memcpy calls are likely one of the very first places you'd check for this exact issue. Many people think it was intentional because of this, but obviously there's zero evidence, because it's basically impossible for evidence for this to exist. And so accordingly there were also 0 direct consequences, besides being in the spotlight for a few minutes and have a bunch of people ask him how it felt to be responsible for such a huge exploit. "It was a simple programming mistake" ad infinitum.
So, in this context - who's going to say no? If any group, criminal or national, wanted to corrupt people - I really don't think it'd be hard at all. Mixing the carrot and the stick really changes the dynamics vs a basic blackmail thing where it's exclusively a personal loss (and with no guarantee that the criminal won't come back in 3 months to do it again). To me, the fact we've basically never had anybody come forward claiming they were a victim of such an effort means that no agency (or criminal organization) anywhere has ever tried this, or that it works essentially 100% of the time.
Absolutely. And that's the point I'm making here. It is essentially impossible to discern between an exploit injected due to malice, and one injected due to incompetence. It reminds one of the CIA's 'simple sabotage field manual' in this regard. [1] Many of the suggestions look basically like a synopses of Dilbert sketches, written about 50 years before Dilbert, because they all happen, completely naturally, at essentially any organization. The manual itself even refers to its suggestions as "purposeful stupidity." You're basically exploiting Hanlon's Razor.
I suppose the point is that even though any given instance of an error like this is overwhelmingly likely to be an innocent mistake, there is some significant probability that one or two such instances were introduced deliberately with plausible deniability. Although this amounts to little more than the claim that "sneaky people might be doing shady things, for all we know", which is true in most walks of life.
> They might not even use blackmail, they might just "help out"
If the target knows or suspects what you’re asking them to do is nefarious then you still run the same risks that they talk before your operation is complete. It’s still far less risky to avoid tipping anyone else off and just slip a trusted asset into a project.
> “I am so and so of the Egyptian intelligence service and would like to blackmail you”
No, but practically by definition the target has to know they’re being forced to “help” and therefore know someone is targeting the project. Some percentage of the time the target comes clean about whatever compromising information was gathered about them, which then potentially alerts the project to the fact they’re being targeted. When it does work you have to keep their mouth shut long enough for your operation to succeed which might mean they have an unfortunate accident, which introduces more risks, or you have to monitor them for the duration which ties up resources. It’s way simpler just to insert a trusted asset into a project.