Snowden is sort of a special case here, as he uses Tails, which has very low adoption, and the value of an exploit is not as large as the value of an exploit in Windows. That said, there have been exploits in Tails:https://www.schneier.com/blog/archives/2014/07/security_vulner_4.html http://www.forbes.com/sites/thomasbrewster/2014/07/21/exploit-dealer-snowdens-favourite-os-tails-has-zero-day-vulnerabilities-lurking-inside/. NSA could probably find one for a few million (consider that a wild guess).

But just a zero day in Tails wouldn't be enough to get Snowden. It would maybe let them get into his accounts, which we would have no idea about unless someone told us, but to silence him, they'd need to delete the files or find where he was. For whatever reason, they are unable to kill him while he's in Russia, and I doubt Snowden keeps the only copy of the files hooked up to his computer while he's online. You can do all your work offline, and only go online while sending something.

(I think they haven't gone and killed Snowden yet because Russia would respond with World War 3. The probability of Russia doing that is high enough to justify inaction. Or in other words, the NSA knows how to lose.)

By the time they already knew who it was, much of those document were already in too many hands to hide. If I was Snowden, I'd have some set up on hidden prepaid hosting set to leak automatically if I didn't keep on cancelling well before anything at all goes public. They wouldn't just have to hack him, but every journalist who may have made copies, anywhere he may have copied it to, etc.

I don't think it's likely that their procedures on spending are that fast. By the time they got approval from whoever needs to approve it, it would be too late to be effective. Most of the damage was already done when Snowden handed over the first batch of documents, and if he suddenly disappeared, media wouldn't forget about him.

not publicising its IP address

Every computer getting info from the blockchain publicises its IP address. But you can use proxies which make it harder, or a pool which has its own servers. But pools have websites, and they make up the majority of mined coins, so there's an attack vector.

I see I wasn't clear again; my "Have I convinced you to change careers yet" was asking if you were planning to become a hacker (or the cleaner version, "security researcher" or "bounty hunter").

You have made me worry more about AI and BCI however, imagining a 'Ghost in the shell' future where people can hack into each other's brains.

I've done my good deed for the day, then.

Incidentally, are you a computer security professional of any form?

No, at least not formally. I have gotten paid for fixing people's computers as a hobby. (I recently got the code for someone's ransomware encrypted computer without having to pay by exploiting the attackers' bitcoin setup. Not as cool as it sounds, they basically used the same address for multiple infections, which was a hole.) I've done a little freelance work in web design and SEO.

I read a lot of Hacker News stuff and elsewhere, use Linux for my own computer (plus Whonix for really sensitive things), but I'm not "officially there". I do want to be someday.

If this is serious, then I'd point out that most of these exploits weren't known by anyone 5 years ago, so they couldn't have been on the lookout for them.

If someone's network was still open after these exploits have been revealed, then they are likely be a honeypot, but the chances of (X is a honeypot: X is vulnerable to this exploit that no one will know about for years) is pretty much the chances of any random computer being a honeypot.

Personally, I think if the NSA had known about Heartbleed as soon as it was introduced (around 2 years before it was fixed), it would have been fixed sooner. Maybe you milk all the data you can out of it, then get it fixed, but having that kind of thing open is a disaster waiting to happen, and NSA would try to fix it sooner.