Watching the iOS 7 jailbreak develop has been interesting, but a bit of concerning news has popped up on Twitter this past weekend. Jailbreak developer iH8sn0w, known for Sn0wbreeze and other tools, tweeted yesterday saying that iOS 7.1 has fixed the ”mobilebackup2 exploit to write to /var via the MediaDomain symlink.” This came as a response to someone asking if it was safe, in iH8sn0w’s opinion, to upgrade to iOS 7.1 beta 2.
.@AshiyaShashwat 7.1 does patch the mobilebackup2 exploit to write to /var via the MediaDomain symlink…
— iH8sn0w (@iH8sn0w) December 15, 2013
Although we don’t have the technical know-how to interpret exactly what the repercussions of this may be, jailbreak tweak developer phoenixdev, known for tweaks Music Controls Pro, Shrink, and others, has taken to Reddit to explain the situation:
Mobilebackup2 is the system used to generate your user backups, as well as place them back on the phone. But it’s designed for only particular folders in the user directory.
It has been used in years past via path walking (prepending ..’s to walk up the directory tree) to let us put files in other places in the /var partition. I’m guessing that they found they could do something similar by creating symlinks to other places on the /var partition.
Actually, I’m not guessing. I know you could do that because a failbreak I once made used that.
P.S. root partition = where the OS is installed; mounted at the base of the filesystem ( / ). /var partition = where the user data is; mounted at /var. When you update your phone, the root partition is overwritten while the var partition stays around. When you restore your phone, both partitions are wiped.
Also, while we can never know what’s genuine when it comes to Stefan Esser, also known as i0n1c, the infamous jailbreak dev has taken to Twitter to say that it appears Apple has indeed patched some of the exploits that were intended for the iOS 7 jailbreak.
So Apple has killed some vulnerabilities jailbreakers were using for iOS 7 in iOS 7.1
— Stefan Esser (@i0n1c) December 16, 2013
The current status of the iOS 7 jailbreak was revealed by pod2g a few days ago, saying to iDesignTimes that “the jailbreak stuff is moving on, but slowly.” With today’s news of an exploit being potentially closed with the iOS 7.1 betas, the best advice would be to avoid them until further notice. iOS 7.0.4 has been confirmed as safe to upgrade to, however, so that’s where I would recommend you stay.