Apple’s recent iOS 4.3.4 update not only patches the PDF security vulnerability, which fuels the JailbreakMe 3.0 tool, but it also prevents “incomplete codesigning attacks” from being made. By detecting and blocking these attacks, Apple has effectively patched all untethered jailbreak exploits that have been used since as far back as iOS 4.1. As i0n1c explains on Twitter, this means that tools that use the current untethered jailbreak exploit, like PwnageTool and redsn0w, cannot be used to jailbreak iOS 4.3.4. While it’s possible for a new untethered jailbreak exploit to be found, it would likely be saved until the public release of iOS 5 this Fall. For those that chose to update to iOS 4.3.4, a tethered jailbreak is available for both Windows and Mac.
For those that did not get it: iOS 4.3.4 does not only fix jbme3 as announced, but also silently kills the ndrv_setspec() integer overflow … In addition to that iOS 4.3.4 also adds code to dyld to detect attacks with binaries using “incomplete codesigning” … [which] were used for all untether exploits from at least iOS 4.1.0