Previously disclosed and patched flaw was reintroduced in iOS 12.4, which could be used in combination with a separate vulnerability to hack into Apple mobile devices
Background
On August 18, unc0ver, a popular jailbreaking software, was updated to version 3.5.0 which includes a public jailbreak on a signed version of Apple’s firmware for the first time in years due to the reintroduction of a previously patched vulnerability (CVE-2019-8605).
unc0ver v3.5.0 is NOW OUT with iOS 12.4 support for A7-A11 devices (Latest and signed firmware)!
— Pwn20wnd is reviving 0-Days (@Pwn20wnd) August 18, 2019
GitHub releases: https://t.co/xwxRUDYbqj
Reddit post: https://t.co/PzpTCxCuIf
Analysis
Earlier this year, security researcher Ned Williamson discovered and reported CVE-2019-8605, a use-after-free vulnerability dubbed “SockPuppet” in the XNU kernel for both iOS and macOS. It was patched by Apple in iOS 12.3 back in May 2019.
Here's the bug. Not entirely clear if this is powerful enough alone for tfp0, but I'm continuing to investigate and look for new bugs. https://t.co/GrrlNnOuNb
— nedwill (@NedWilliamson) May 20, 2019
In July 2019, Williamson released SockPuppet and SockPuppet2, exploit code that “achieves kernel_task port” or task_for_pid(0) (tfp0), which is highly sought after for jailbreaking Apple devices.
However, following the release of iOS 12.4 on July 22, 2019, it appears that the SockPuppet flaw was unintentionally reintroduced. It was eventually incorporated into unc0ver version 3.5.0 to allow iPhone and iPad users to jailbreak their devices running the latest signed version of iOS. A subsequent update to unc0ver, version 3.5.1, credits security researcher Umang Raghuvanshi for his own variation on SockPuppet, dubbed SockPuppet 3.0, for its “amazing exploit reliability” on iOS 12.4.
The reintroduction of the SockPuppet vulnerability, along with the availability of the unc0ver jailbreak means that certain Apple iPhone and iPad Devices running specific iOS versions are not only vulnerable to being jailbroken, but also exploited by attackers.
Stefan Esser, a security researcher known as i0n1c, tweeted out a warning that users should also be careful about downloading apps from the App Store because a malicious app “could have a copy of the jailbreak in it” and he expects criminals to “incorporate this into Apps and submit to the iOS AppStore” soon.
I hope people are aware that with a public jailbreak being available for the latest iOS 12.4 people must be very careful what Apps they download from the Apple AppStore. Any such app could have a copy of the jailbreak in it.
— Stefan Esser (@i0n1c) August 19, 2019
Affected Versions
The following is a list of iOS versions and Apple devices that are affected by the SockPuppet vulnerability and the unc0ver jailbreak.
| iOS Version | Impact |
|---|---|
| iOS 11.0 through 11.4.1 | Affected |
| iOS 12.0 through 12.2 | Affected |
| iOS 12.3, iOS 12.3.1 | Not Affected |
| iOS 12.3.2 (iPhone 8 Plus) | Not Affected |
| iOS 12.4 (Current Version) | Affected |
| iOS 13 (Beta Version) | Not Affected |
| Apple Devices | Apple Processor | Impact |
|---|---|---|
| iPhone 5S, iPad Air, iPad Mini 2, iPad Mini 3 | Apple A7 | Affected |
| iPhone 6, iPhone 6 Plus, iPod Touch (6th Generation), iPad Mini 4 | Apple A8 | Affected |
| iPad Air 2 | Apple A8X | Affected |
| iPhone 6S, iPhone 6S Plus, iPhone SE, iPad (5th Generation) | Apple A9 | Affected |
| iPad Pro (9.7” and 12.9”) | Apple A9X | Affected |
| iPhone 7, iPhone 7 Plus, iPad (6th Generation), iPod Touch (7th Generation) | Apple A10 Fusion | Affected |
| iPad Pro (10.5” and 12.9”) | Apple A10X Fusion | Affected |
| iPhone 8, iPhone 8 Plus, iPhone X | Apple A11 Bionic | Affected |
| iPhone XS, iPhone XS Max, iPhone XR, iPad Mini (2019), iPad Air (2019) | Apple A12 Bionic | Partially Affected |
| iPad Pro (11” and 12.9”) | Apple A12X Bionic | Partially Affected |
A newer release of unc0ver, version 3.5.3, includes “partial support” for some Apple A12 and A12X devices on iOS 12.1.3, 12.1.4, 12.2 and 12.4.
Proof of concept
As previously referenced, exploit code for SockPuppet and SockPuppet 2 have been available since July 2019 and the updated exploit code for SockPuppet 3 is included in unc0ver versions 3.5.1 and later.
Solution
No new patch for the reintroduced SockPuppet vulnerability had been released at the time this blog was published. However, users running specific versions of iOS, such as 12.3, 12.3.1, 12.3.2 (iPhone 8 Plus) and 13 (beta releases) are not affected and are advised to remain on these versions until a patch is available. We anticipate that Apple will release an iOS update in the coming days.
Identifying affected systems
Tenable products offer integration with Mobile Device Management (MDM) solutions to identify mobile devices missing vendor updates. Once a patch is available, a list of our MDM plugins to identify vulnerable devices will appear here as they’re released.
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