Because we at SektionEins believe keeping the public in the dark about details of already fixed vulnerabilities is wrong...
...use our private jailbreak...
i.e. your undisclosed vulnerabilities bad, my undisclosed vulnerabilities are cool.
Useful analysis, but casting a marketing endeavor as a public service is rather disingenuous.
What a jailbreak is worth these days.. close to a million? So training course for a few grand by someone capable of developing a jailbreak (on numerous occasions*) should be a well-spent educational investment, even if no unfixed vulnerabilities are shared (obviously, they won't be).
I understand the difference. I don't see the distinction. They know an unpatched vulnerability and if they haven't reported it to Apple, they don't own the moral high ground that would justify their smug public-interested belief.
In fact, as someone who lives and breathes in this ecosystem and gives talks on the ethics involved, I kind of want to argue the opposite: that doing a play-by-play breakdown of a recent bug to the point of educating an attacker how to exploit it, you increase everyone's danger and don't particularly increase their safety, while disclosing a bug being hoarded in a "just me and a ton of my close friends over a long period of time" (which is not how the groups who enjoy publishing public jailbreaks play the game) in a high-level way would actually do the opposite.
Once again demonstrating that the term "zero day" is horribly overused and misused and probably should be eliminated from the lexicon, the OSUnserializeBinary bug doesn't appear to be new. Brandon Azad[1] says he discovered it last year. It was fixed in OS X in May. Or maybe the fix didn't work since they had to make another patch this week.
Keep this in mind when you think about Apple's recent bug bounty program. Anyone who has been sitting on some private jailbreaks might be tempted to collect $200k, no?
Useful analysis, but casting a marketing endeavor as a public service is rather disingenuous.