CVE-2018-4390 in watchOS
Summary
by MITRE • 10/28/2020
An inconsistent user interface issue was addressed with improved state management. This issue is fixed in macOS High Sierra 10.13.1, Security Update 2017-001 Sierra, and Security Update 2017-004 El Capitan, watchOS 4.3, iOS 12.1. Processing a maliciously crafted text message may lead to UI spoofing.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/27/2020
The vulnerability identified as CVE-2018-4390 represents a significant user interface consistency issue that could potentially be exploited for malicious purposes within Apple's operating systems. This flaw specifically affects the state management mechanisms that govern how user interfaces behave during text message processing, creating opportunities for attackers to manipulate the visual presentation of applications. The issue was particularly concerning because it could be triggered by processing maliciously crafted text messages, which are commonly encountered in everyday communication scenarios. The vulnerability was addressed through comprehensive updates released for multiple Apple platforms including macOS High Sierra 10.13.1, Security Update 2017-001 for Sierra, Security Update 2017-004 for El Capitan, watchOS 4.3, and iOS 12.1, demonstrating the widespread nature of the potential impact across Apple's ecosystem.
The technical nature of this vulnerability stems from inadequate state management within the user interface components responsible for handling text message processing. When a user encounters a maliciously crafted text message, the application's state management system fails to properly maintain consistent interface elements, potentially allowing an attacker to manipulate how the interface appears to the user. This inconsistency could manifest in various ways such as altered button positions, modified text display, or other visual elements that might mislead users about the actual functionality or security status of the application. The flaw essentially creates a condition where the user interface does not accurately reflect the underlying system state, opening possibilities for UI spoofing attacks that could deceive users into making incorrect security decisions. This type of vulnerability is classified under CWE-691, which deals with insufficient control flow management, and specifically relates to improper state management in user interface components.
The operational impact of CVE-2018-4390 extends beyond simple visual inconsistencies to potentially enable more serious security attacks through user deception. UI spoofing attacks can be particularly dangerous because they exploit human trust in familiar interface elements, making them difficult to detect and potentially leading to successful social engineering attempts. An attacker could craft text messages that, when processed by vulnerable systems, cause the interface to display misleading information or alter the appearance of security warnings. This could result in users unknowingly granting permissions, entering credentials, or performing other security-sensitive actions based on manipulated interface elements. The vulnerability's presence across multiple Apple platforms including mobile and desktop operating systems amplifies its potential impact, as users frequently interact with these systems in environments where security awareness may be lower. The attack vector through text message processing is particularly concerning given the prevalence of messaging applications and the volume of text-based communication that occurs daily.
The remediation for CVE-2018-4390 required comprehensive updates across Apple's platform ecosystem, with each release addressing the underlying state management inconsistencies that led to the UI spoofing vulnerability. These updates implemented improved state management protocols that ensure user interface elements maintain consistent behavior regardless of input content, particularly when processing text messages. The security patches specifically focused on strengthening the interface state management mechanisms to prevent the type of inconsistencies that could be exploited for UI spoofing attacks. Organizations and users should prioritize applying these security updates to protect against potential exploitation of this vulnerability. The mitigation strategy emphasizes the importance of maintaining up-to-date system software, as this vulnerability could be exploited through common communication channels like SMS, iMessage, and other text-based messaging platforms. Additionally, security teams should consider implementing monitoring for unusual text message processing activities that might indicate exploitation attempts, though the nature of this vulnerability makes detection particularly challenging due to its subtle interface manipulation characteristics.