CVE-2018-4339 in iOS
Summary
by MITRE • 10/28/2020
This issue was addressed with a new entitlement. This issue is fixed in iOS 12.1. A local user may be able to read a persistent device identifier.
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Analysis
by VulDB Data Team • 11/27/2020
The vulnerability described in CVE-2018-4339 represents a privacy and security concern within Apple's iOS operating system that allowed unauthorized access to persistent device identifiers. This issue specifically affected iOS versions prior to 12.1, where a local user could potentially exploit a flaw in the system's entitlement mechanisms to read device identifiers that should have remained protected. The vulnerability stems from insufficient access controls and improper entitlement management within the iOS security framework, creating a pathway for malicious actors to obtain sensitive device information that could be used for tracking or identification purposes.
The technical flaw in CVE-2018-4339 resides in how iOS manages device identifier access controls and entitlement validation. This vulnerability falls under the category of improper access control as defined by CWE-284, where the system fails to properly restrict access to sensitive device information. The issue is particularly concerning because persistent device identifiers are designed to remain stable across device reboots and application launches, making them valuable for tracking user behavior and maintaining device fingerprinting capabilities. When a local user can read these identifiers, it creates a potential attack vector that could be exploited to build detailed profiles of device usage patterns and user preferences.
The operational impact of this vulnerability extends beyond simple privacy concerns to encompass broader security implications for iOS users. Attackers who successfully exploit this flaw could potentially correlate device identifiers across different applications and services, creating comprehensive tracking profiles that undermine user privacy expectations. This capability could enable sophisticated tracking campaigns where malicious actors monitor user activities across multiple platforms and applications, effectively bypassing normal privacy protections. The vulnerability's local nature means that it requires physical access to the device or the ability to execute code on the device, but once exploited, it could provide persistent access to device identifiers that remain stable over time.
The remediation for CVE-2018-4339 was implemented through a new entitlement mechanism introduced in iOS 12.1, which strengthened access controls for device identifier information and properly enforced entitlement validation. This fix aligns with the principle of least privilege and proper access control enforcement that is fundamental to secure system design. Organizations should ensure their iOS devices are updated to version 12.1 or later to mitigate this vulnerability, as the patch addresses the underlying entitlement management issues that allowed unauthorized access to persistent identifiers. The fix demonstrates Apple's approach to addressing security flaws through improved entitlement validation and access control mechanisms, which is consistent with industry best practices for maintaining device security and user privacy.
This vulnerability also relates to several ATT&CK framework techniques including T1059.001 for execution through command and scripting interpreter and T1070.004 for indicator removal on host, as attackers might use device identifier information to create more sophisticated tracking capabilities or remove traces of their activities. The remediation approach taken by Apple reflects the importance of proper entitlement management and access control enforcement in preventing unauthorized data access, which is critical for maintaining the security posture of mobile operating systems. Organizations should monitor for similar entitlement-related vulnerabilities and ensure their mobile device management policies include regular updates and security assessments to prevent exploitation of similar access control flaws.