SANS ISC: Out-of-Band iOS Patch Fixes 0-Day Vulnerabilities - Internet Security | DShield

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SANS ISC InfoSec Forums

A new spyware has been discovered on the Apple platform. Called Pegasus [1], it turns out to be a sophisticated targeted spyware. Developed by professionals, it uses 0-day vulnerabilities, code obfuscation and encryption techniques.

Apple released today an out-of-band patch for iOS (version 9.3.5) [2]. It fixes three critical vulnerabilities:

CVE-2016-4655 (Memory Corruption in Safari Webkit)
A memory corruption vulnerability exists in Safari Webkit that allows an attacker to execute arbitrary code. Pegasus exploits this vulnerability to obtain initial code execution privileges within the context of the Safari web browser.

CVE-2016-4656 (Kernel Information Leak Circumvents KASLR) 
Before Pegasus can execute its jailbreak, it must determine where the kernel is located in memory. Kernel Address Space Layout Randomization (KASLR) makes this task difficult by  mapping the kernel into different and unpredictable locations in memory. 

CVE-2016-4657 (Memory Corruption in Kernel leads to Jailbreak)
The third vulnerability in Pegasus’ Trident is the one that is used to jailbreak the phone. A memory corruption vulnerability in the kernel is used to corrupt memory in both the 32- and 64-bit versions. The exploits are performed differently on each version.

Check on the Apple website if the patch is available for your device and install it as soon as possible (via the usual way: iTunes or Software Updates on your device)

[1] https://info.lookout.com/rs/051-ESQ-475/images/lookout-pegasus-technical-analysis.pdf
[2] https://support.apple.com/en-us/HT207107

Xavier Mertens (@xme)
ISC Handler - Freelance Security Consultant
PGP Key