Is it ethical for these researchers to pay hackers for access to malware before it’s unleashed?

"That is, what if everyone, not just these researchers, gave $22,500 to the Shadow Brokers? Patrick Lin, a philosophy professor at California Polytechnic State University, said it’s also worth considering what would happen if a third outside group crowd-funded money to limit the effectiveness of the researchers themselves. How would that turn out?

“Of course, it matters how you formulate the deontological rule and apply it to your situation; and this is a known problem for deontology,” Lin said. “If you interpret the Golden Rule as having an exception for malicious actors—that we can do things to them that they should not do to us, which doesn’t seem unreasonable—then that could raise further questions.”"