CVE-2018-4122 in iCloud
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11.3 is affected. Safari before 11.1 is affected. iCloud before 7.4 on Windows is affected. iTunes before 12.7.4 on Windows is affected. tvOS before 11.3 is affected. watchOS before 4.3 is affected. The issue involves the "WebKit" component. It allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site.
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Analysis
by VulDB Data Team • 02/08/2021
The vulnerability identified as CVE-2018-4122 represents a critical memory corruption flaw within Apple's WebKit rendering engine that affected multiple Apple operating systems and applications. This vulnerability resides in the core web browsing component that powers Safari browsers across iOS, macOS, and tvOS platforms, as well as in the desktop applications like iTunes and iCloud on Windows. The flaw manifests when WebKit processes maliciously crafted web content, creating a pathway for remote attackers to execute arbitrary code on affected systems. The vulnerability affects iOS versions prior to 11.3, Safari versions prior to 11.1, iCloud versions prior to 7.4 on Windows, iTunes versions prior to 12.7.4 on Windows, tvOS versions prior to 11.3, and watchOS versions prior to 4.3, demonstrating the widespread impact across Apple's ecosystem.
The technical nature of this vulnerability stems from improper memory handling within the WebKit component's JavaScript engine, specifically related to how it processes certain data structures and memory allocations. This memory corruption issue occurs when malicious web pages attempt to exploit buffer overflows or use-after-free conditions in the WebKit rendering engine's memory management system. The flaw allows attackers to manipulate memory pointers and overwrite critical system memory regions, potentially leading to arbitrary code execution with the privileges of the compromised application. The vulnerability is particularly dangerous because it can be triggered through simple web browsing activities, requiring no user interaction beyond visiting a malicious website, making it a prime candidate for drive-by attack scenarios.
The operational impact of CVE-2018-4122 extends far beyond individual user devices, as it represents a significant threat vector for nation-state actors and cybercriminal organizations seeking to compromise Apple users en masse. The vulnerability's ability to cause both remote code execution and denial of service makes it particularly attractive for attackers who may want to establish persistent access to target systems or simply disrupt service availability. When exploited successfully, the vulnerability can lead to complete system compromise, data exfiltration, and the installation of backdoors or malware on affected devices. The fact that this vulnerability affects multiple platforms including mobile operating systems, desktop applications, and web browsers creates a broad attack surface that increases the likelihood of successful exploitation across different threat scenarios.
Security professionals should implement immediate mitigations including prompt installation of the relevant Apple security updates that address this vulnerability through patched versions of WebKit and the affected applications. Organizations should also deploy network-based intrusion detection systems to monitor for exploitation attempts and consider implementing web content filtering solutions to block access to known malicious domains. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions, both of which are common memory corruption patterns. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1059.007 for command and scripting interpreter and T1190 for exploitation of remote services, demonstrating how attackers can leverage browser-based vulnerabilities to establish persistent access to target systems. Additionally, organizations should conduct comprehensive vulnerability assessments to ensure all affected Apple products are updated and implement security awareness training to help users recognize potentially malicious web content.