Pierluigi Paganini July 01, 2015

Although Apple has fixed the Masque Attack there are still other attack scenarios that an attacker can exploit in the installation process on iOS.

A team of researchers at FireEye has revealed that the last update issued by Apple only partially fixed the two vulnerabilities exploited in the Masque Attack (CVE-2015-3722/3725, and CVE-2015-3725). The two exploits were dubbed by the experts Manifest Masque and Extension Masque and can be used to demolish mobile apps.

The experts explained that this vulnerability affects all iOS 7.x and iOS 8.x versions prior to iOS 8.4.

“In the recent release of iOS 8.4, Apple fixed several vulnerabilities, including vulnerabilities that allow attackers to deploy two new kinds of Masque Attack (CVE-2015-3722/3725, and CVE-2015-3725). We call these exploits Manifest Masque and Extension Masque, which can be used to demolish apps, including system apps (e.g., Apple Watch, Health, Pay and so on), and to break the app data container. In this blog, we also disclose the details of a previously fixed, but undisclosed, masque vulnerability: Plugin Masque, which bypasses iOS entitlement enforcement and hijacks VPN traffic.” wrote the blog post published by FireEye.

The experts also highlighted that around one-third of iOS devices still have not updated to versions 8.1.3 or above, leaving the devices open to the Masque Attacks.

Researchers Zhaofeng Chen, Tao Wei, Hui Xue, and Yulong Zhang provided the details a number of ‘app-demolishing’ Masque attacks, these malicious apps could be downloaded from the official App Store or can be part of a system app such as the Apple Pay or the Safary Browser.

“The Manifest Mmasque attack leverages the vulnerability (CVE-2015-3722, CVE-2015-3725) to demolish an existing app on iOS when a victim installs an in-house iOS app wirelessly using enterprise provisioning from a website,” states the post. “The demolished app can be either a regular app downloaded from official App Store or even an important system app, such as Apple Watch, Apple Pay, App Store, Safari, and Settings.

One of the attack scenarios detailed by the experts, the Plugin Masque allows executing Untrusted Code with Privilege including VPN-hijacking by replacing the VPN Plugin in affected devices.

“… this exploit is even more severe than the original Masque Attack,” states the experts. “The malicious code can be injected to the neagent process and can perform privileged operations, such as monitoring all VPN traffic, without the user’s awareness.”

“Our investigation also shows that around one third of iOS devices still have not updated to versions 8.1.3 or above, even five months after the release of 8.1.3, and these devices are still vulnerable to all the Masque attacks.”

Apple users should update their devices urgently.

Pierluigi Paganini

(Security Affairs –Masque attacks, mobile)