(1) You are effective at finding the specific kinds of vulnerabilities that the grey market actually purchases. People have _very_ weird ideas about what the grey market wants. In reality, if your bug isn't a drive-by clientside in a popular client, it is unlikely that anyone wants to buy it.
(2) You are willing to get your hands dirty with shady purchasers. If you're talented, you can make good money in the grey market, or you can retain plausible deniability about what your work is being used for, but you can't do both of those things.
That first case is really the limiting factor. And remember, if you can reliably sell bugs to the grey market, that strongly implies you have lucrative options in the legitimate market. Bug bounties are not the most competitive alternative to the grey market!
> In reality, if your bug isn't a drive-by clientside in a popular client, it is unlikely that anyone wants to buy it.
That sounds like black market buyers (maybe we disagree on where the "gray" line is). Governments are very interested in bugs that allow pivoting and lateral movement.
1. If you have to ask this question, you are quite far from being able to do it any time soon (and that's assuming you can find the vulnerabilities!),
2. You will predominantly sell your vulnerabilities, preferably weaponized as complete exploits, to firms that specialize in "vulnerability research" and "exploitation development" with close ties to government agencies.
It's much easier to find a firm that can act as a broker between you and the government agency than it is to knock on the right doors to sell it on your own, with no background or prior contact.
(1) You are effective at finding the specific kinds of vulnerabilities that the grey market actually purchases. People have _very_ weird ideas about what the grey market wants. In reality, if your bug isn't a drive-by clientside in a popular client, it is unlikely that anyone wants to buy it.
(2) You are willing to get your hands dirty with shady purchasers. If you're talented, you can make good money in the grey market, or you can retain plausible deniability about what your work is being used for, but you can't do both of those things.
That first case is really the limiting factor. And remember, if you can reliably sell bugs to the grey market, that strongly implies you have lucrative options in the legitimate market. Bug bounties are not the most competitive alternative to the grey market!