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Posts tagged ‘App Store’

8
Nov

Charlie Miller Discovers iOS Code-Signing Bypass Vulnerability

Security researcher Charlie Miller (@0xcharlie) has discovered a significant flaw in iOS which may allow a malicious app on the App Store to download and execute arbitrary unsigned code. What this means for iPhone, iPad and iPod Touch users is that installing a malicious app may allow an attacker to obtain shell access to your device, and download contacts or images.

Apple reviews every app submitted to the App Store, which has meant that iOS users have not had to worry about outright malware. Since this vulnerability allows the apps to fetch code remotely, they can perform actions not reviewed by the App Store staff. Charlie had submitted a proof-of-concept app that was approved (see video below), but has since been removed by Apple.

The reason this vulnerability works is based around some changes Apple made in iOS 4.3 last year, which allowed Mobile Safari to run javascript at a more privileged level on the devices. This change required Apple to make an exception for Safari to execute unsigned code in a particular area of memory. Charlie Miller’s bug is allegedly a very unique case that allows any app to take advantage of this, and hence run their own unsigned code.

Charlie will be presenting the vulnerability in detail at the SysCan conference in Taiwan next week. Apple has already released a developer beta of iOS 5.0.1 which patches the recent iPad Smart Cover lock screen bypass, but I would not be at all surprised if they release another beta which includes a fix for this bug. Until then, be careful to only install apps from developers you trust.

[Update] Apple has kicked Charlie out of the Developer program. At first I felt that this was an extremely bad reaction on Apple’s part. That said, Apple is probably most upset that Charlie’s proof-of-concept app could have been installed by legitimate users. Regardless of Charlie’s intentions, this could constitute malware, and he should have removed the app as soon as he saw the flaw existed. The posting of his video above probably didn’t help matters either.

7
Jun

Find My iPhone Brings Improved Offline Device Support

Apple has released an update to their free Find My iPhone offering, which greatly improves the support for tracking devices that are offline at the time. Note that this doesn’t mean you can track an iPhone or iPad that is turned off, or out of signal range (not possible). Instead, if a device is offline when you try to locate it, Apple will later send you an email with its location the next time that device gets back online. Thanks to this, it’s no longer necessary to constantly be checking the Find My iPhone app/webpage. Here is Apple’s summary of the changes:

  • When you are unable to locate a device because it is offline, you will receive an email if the device comes online and is located.
  • Ability to remove an offline device from the list using the app.

Note, it appears this updated feature is only available using the Find My iPhone app (version 1.2) available in the App Store – it is not yet available in the MobileMe web interface. I assume it won’t be updated until the new iCloud Find My iPhone web interface is launched. [Update: I was right.]

For more information on how to use this great free service to recover your iOS devices, check out Protecting and Recovering Your iPhone and iPad from Loss and Theft.

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