CVE-2018-4127 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. 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-2018-4127 represents a critical memory corruption flaw within Apple's WebKit rendering engine that affected multiple Apple products and operating systems. This vulnerability resides in the core web browsing component that powers Safari, iOS web views, and other Apple applications that utilize WebKit for web content rendering. The flaw manifests when WebKit processes specially crafted web content that triggers memory corruption conditions, potentially allowing remote attackers to execute arbitrary code on affected systems. The vulnerability impacts iOS versions prior to 11.3, Safari versions prior to 11.1, iCloud for Windows versions prior to 7.4, iTunes for Windows versions prior to 12.7.4, and tvOS versions prior to 11.3, demonstrating the widespread nature of the WebKit component across Apple's ecosystem.
The technical nature of this vulnerability falls under memory corruption patterns that can lead to arbitrary code execution or denial of service conditions. When a malicious website delivers crafted content that exploits the WebKit memory handling mechanisms, it can cause buffer overflows, use-after-free conditions, or other memory management errors that result in unpredictable behavior. Attackers can leverage this vulnerability by hosting malicious web content that, when loaded in a vulnerable browser or application, triggers the memory corruption. The exploitation process typically involves crafting specific HTML, JavaScript, or other web content that causes WebKit to mishandle memory allocation or deallocation, leading to memory corruption that can be leveraged for code execution. This type of vulnerability is particularly dangerous because it allows remote code execution without requiring user interaction beyond visiting a malicious website, making it a prime target for drive-by attacks.
The operational impact of CVE-2018-4127 extends beyond simple denial of service scenarios to include potential complete system compromise. Attackers who successfully exploit this vulnerability can gain arbitrary code execution privileges on affected devices, potentially leading to full system compromise, data theft, or persistent backdoor installation. The vulnerability affects both mobile and desktop platforms, including iOS devices, macOS systems, and Windows applications, making it a multi-platform threat. The impact is particularly severe for enterprise environments where users may access untrusted websites or where the vulnerability could be leveraged to establish persistent access to corporate networks. Organizations using Apple products for business operations face significant risk as this vulnerability can be exploited through standard web browsing activities, making it difficult to defend against through traditional network security controls. The vulnerability's presence in core system components like WebKit means that multiple applications and platforms are simultaneously affected, amplifying the potential attack surface and impact.
Mitigation strategies for CVE-2018-4127 primarily focus on immediate patching and system updates to address the underlying WebKit memory corruption issue. Apple released security updates for all affected versions including iOS 11.3, Safari 11.1, iCloud 7.4, iTunes 12.7.4, and tvOS 11.3, which fixed the memory handling flaws in the WebKit component. Organizations should prioritize immediate deployment of these security patches across all affected Apple platforms, particularly in enterprise environments where the risk of targeted attacks is higher. Network administrators should implement web filtering solutions and browser security controls to prevent access to known malicious domains while waiting for patches to be deployed. Security monitoring should include detection of unusual browser behavior or memory usage patterns that might indicate exploitation attempts. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping their systems updated with the latest security patches. The vulnerability highlights the importance of maintaining up-to-date software across all platforms and demonstrates how a flaw in a core rendering engine can affect multiple applications and operating systems. This vulnerability aligns with CWE-122 (Heap-based Buffer Overflow) and CWE-125 (Out-of-bounds Read) categories, and represents a typical example of techniques used in the ATT&CK framework under the T1059 (Command and Scripting Interpreter) and T1071 (Application Layer Protocol) tactics for remote code execution.