Two things happened to shrink the jailbreak community over the years: 1) Apple became more adept at patching up security holes in a timely fashion and even began employing hackers to improve its defenses and 2) Apple has added tons of functionality to iOS that made jailbreaking not worth the time or added security risk. For those that are still adamant about jailbreaking, there is some good news on that front coming Twitter user axi0mX. axi0mX claims to have leveraged what is being called a "checkm8" exploit in order to potentially deliver an "epic jailbreak".
EPIC JAILBREAK: Introducing checkm8 (read "checkmate"), a permanent unpatchable bootrom exploit for hundreds of millions of iOS devices.— axi0mX (@axi0mX) September 27, 2019
Most generations of iPhones and iPads are vulnerable: from iPhone 4S (A5 chip) to iPhone 8 and iPhone X (A11 chip). https://t.co/dQJtXb78sG
This checkm8 exploit could deliver a working, permanent jailbreak that Apple cannot patch against:
The last iOS device with a public bootrom exploit until today was iPhone 4, which was released in 2010. This is possibly the biggest news in iOS jailbreak community in years. I am releasing my exploit for free for the benefit of iOS jailbreak and security research community.
axi0mX goes on to state:
What I am releasing today is not a full jailbreak with Cydia, just an exploit. Researchers and developers can use it to dump SecureROM, decrypt keybags with AES engine, and demote the device to enable JTAG. You still need additional hardware and software to use JTAG.
The reason that Apple can't patch this exploit is because it is in the bootrom, which is read-only memory that can't be patched via security updates that Apple pushes over-the-air (OTA). In addition, this potential jailbreak would only be possible over USB, which means that it is "tethered" and has to be triggered upon each subsequent boot of an iPhone. However, axi0mX believes that further development could lead to an untethered jailbreak which would be persistent even after a device is rebooted.
When all is said and done, axi0mX claims that all iOS devices dating back to the iPhone 4S and ending with the iPhone 8/iPhone 8 Plus/iPhone X could be jailbroken permanently. Will this spark a new era in jailbreaking for iPhone users? It remains to be seen, but is nonetheless a big development for those that follow this subset of the iPhone community.