Apple Kills Untethered Jailbreaking in iOS 4.3.4


Image courtesy of Christian Bryan on Flickr
Image courtesy of Christian Bryan on Flickr

Apple released its promised iOS 4.3.4 software towards the end of last week to fix a security vulnerability in mobile Safari that made the latest JailbreakMe exploit possible. It goes without saying, then, that updating your device will eliminate the possibility of jailbreaking with JailbreakMe, but it will also kill all other untethered jailbreaks too!

Just like iOS 5, iOS 4.3.4 blocks the untethered exploit that jailbreakers have been using since iOS 4.1. Ion1c, the hacker responsible for the first untethered jailbreak of iOS 4.3, explained Apple’s fix in messages posted to Twitter:

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 code signing”.

“Incomplete codesigning attacks” were used for all untether exploits from at least iOS 4.1.0

Wonder if [Apple] only tried to stop my xploit from modifying LCs at runtime with the new check, or if they knew it would stop [incomplete codesigning] attacks.

Until the iPhone Dev-Team finds another method of untethered jailbreaking then, you’re stuck with a tethered option… unless, of course, you cling on to your iOS 4.3.3 firmware. That might be easy to do now, but will you be able to put up with it when all your friends upgrade to iOS 5 this fall?

For those that do want to upgrade and are happy to go ahead with a tethered solution, you’ll be pleased to know RedSn0w was updated last week to work with Apple’s latest iOS release.

[via iDB]

  • James Campbell-Harris

    No updates for the Verizon phone! Looks like I can keep my untethered jailbreak on there!

  • justy84wvu

    I want to update as this jailbreak has done weird things to my phone, yet Windows won’t acknowledge my iPhone at all. I’ve reinstalled iTunes, restarted, changed USB ports and nothing. The phone charges but won’t sync. Anyone have some helpful ideas I can try other than buying a Mac? 

  • Tom McGrath

    As a none jailbreaker, may someone explain the meanings of tethered and untethered jailbreaking?

  • Wesley Campbell

    Tethered means connected to a computer through a cord to jailbreak so untethered means you can simply download a file on the internet on your device. Then instantly your device is jailbroken.

  • Hampus

    Nope, Wesley, that’s incorrect.

    The difference is that with a with an untethered jailbreak you will basically have to connect the device to your computer and run the jailbreak tool again (often in a mode just made for this) every time you have to restart (hardware reset) or respring (software reset) (i think it includes resprings at least) the device as it will otherwise get stuck at the Apple icon while loading.

    An unthethered jailbreak is then of course a jailbreak without those problems, the device can restart without the help of a computer.

  • Hampus

    I suggest you google iphone reset mode and DFU mode, one of those should help if you are confident enough to try them, they can be bit tricky to get out of sometimes if you don’t know what you are doing.

    You could also take a look at Apples support “Forum”, can’t remember what it’s named now, or ask at your closest Apple store or certified reseller/service provider.
    Make sure only to mention wanting to restore and iTunes not recognizing the device, the warranty doesn’t apply to jailbreak devices afterall and Apple provides no support for it.

    Last, you can always look at popular ios fan forums and jailbreak forums like and, they should be able to help.

  • Hampus

    Sigh, I hope they can find a new exploit that lets them make it untethered.
    Sure, iOS 5 helps a lot but there are still problems with iOS that I can only fix by jailbreaking…

  • aaron__b

    Why do you answer people if you have no idea what you are talking about?

  • djrobsd

    i’ll stick w my 4.3.3 until an untethered 5 comes out… 

  • huyett

    Software engineers will never keep freelancing hackers at bay.  They can plug one hole, but hackers will find another exploit in the near future I suspect.