Apple's iOS & macOS Contacts Vulnerability - Privacy Preferences Bypass

12 Sep 2022

A vulnerability has been identified in iOS/iPadOS < 15.7 / < 16.0 and macOS Big Sur < 11.7 that allows an app to bypass Privacy preferences, posing a significant risk. The vulnerability, classified as Improper Input Validation affects the Contacts component. Users are strongly encouraged to update their devices to the latest version to protect their data.

Details

Product: Apple iOS/iPadOS, macOS
Affected Version: iOS/iPadOS < 15.7 / < 16.0, macOS Big Sur < 11.7
Vulnerability Type: Improper Input Validation (CWE-20)
Risk Level: Medium
Vendor URL: https://www.apple.com
Vendor acknowledged vulnerability: Yes
Vendor Status: Fixed
CVE: CVE-2022-32854

The vulnerability exists because the CNContactPickerViewController class allows the selection of contacts without prompting the user for access permissions. By exploiting a specific predicate (predicateForEnablingContact) with a custom selector, it is possible to inject Objective-C method calls into a internal service component. This can lead to serious breaches, such as a malicious app accessing sensitive data without user consent.

Exploitation

The vulnerability was demonstrated using two exploits:

Control Program Flow:
- By calling indexOfObjectPassingTest: on an NSArray object with an NSData object as a parameter, a type confusion occurs. The NSData object is used as a block, where its content is treated as a function pointer. This exploit can access various data such as Calendar, Contacts, Photos, and Camera.
Send Conditional HTTP Requests:
- By calling initWithContentsOfURL: on an NSData object, the app can send HTTP requests. This can extract contact data from a local app using HTTP requests as a feedback mechanism.

Impact

Exploitation of this vulnerability by an attacker could have serious privacy implications. Accessing Calendar, Contacts, Photos, and Camera data without user consent can lead to data leakage and unauthorized data manipulation.

Telekom Security