CVE-2018-4198 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. tvOS before 11.4 is affected. watchOS before 4.3.1 is affected. The issue involves the "UIKit" component. It allows remote attackers to cause a denial of service via a crafted text file.
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Analysis
by VulDB Data Team • 07/26/2024
The vulnerability identified as CVE-2018-4198 represents a critical denial of service flaw within Apple's UIKit framework affecting multiple operating systems including iOS, macOS, tvOS, and watchOS. This security weakness stems from inadequate input validation mechanisms within the text rendering components of these platforms, creating an exploitable condition that remote attackers can leverage to disrupt system functionality. The affected versions encompass iOS 11.3 and earlier, macOS 10.13.4 and earlier, tvOS 11.3 and earlier, and watchOS 4.3 and earlier, indicating a widespread impact across Apple's ecosystem.
The technical nature of this vulnerability resides in how UIKit processes text files, specifically when handling malformed or crafted text input. When a specially constructed text file is processed by the affected systems, the UIKit component fails to properly validate the input structure, leading to a crash or hang condition that results in complete system denial of service. This flaw operates at the application layer and requires no privileged access or authentication to exploit, making it particularly dangerous as it can be triggered through various means including email attachments, web content, or file downloads. The vulnerability manifests as an unhandled exception in the text rendering pipeline, causing the affected application or system component to terminate unexpectedly.
The operational impact of CVE-2018-4198 extends beyond simple service disruption, potentially affecting user productivity and system availability across Apple devices. Attackers can remotely trigger this vulnerability through text-based content delivered via email, web browsers, or file sharing applications, causing devices to become unresponsive or requiring manual restarts. This type of vulnerability directly impacts the availability component of the CIA triad and can be classified under CWE-129 as "Improper Validation of Input" or CWE-248 as "Uncaught Exception." The vulnerability aligns with ATT&CK technique T1499.004 for "Endpoint Denial of Service" and represents a significant concern for enterprise environments where device reliability is paramount.
Mitigation strategies for this vulnerability require immediate system updates to the patched versions of affected operating systems, specifically iOS 11.4, macOS 10.13.5, tvOS 11.4, and watchOS 4.3.1. Organizations should implement proactive patch management policies to ensure all affected devices receive updates promptly, as the vulnerability can be exploited remotely without user interaction. Network administrators should consider implementing content filtering measures to block suspicious text files and monitor for unusual system behavior that might indicate exploitation attempts. The vulnerability demonstrates the importance of robust input validation in GUI frameworks and highlights the need for comprehensive security testing of user interface components. Security teams should also consider implementing endpoint detection and response solutions to monitor for potential exploitation attempts and maintain detailed logs of system events that could indicate successful exploitation of this denial of service condition.