CVE-2016-7640 in iCloud
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.2 is affected. Safari before 10.0.2 is affected. iCloud before 6.1 is affected. iTunes before 12.5.4 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 • 10/07/2022
The vulnerability identified as CVE-2016-7640 represents a critical memory corruption flaw within Apple's WebKit rendering engine that affected multiple Apple products including iOS versions prior to 10.2, Safari versions before 10.0.2, iCloud versions before 6.1, and iTunes versions before 12.5.4. This vulnerability resides in the WebKit component which serves as the core web browser engine responsible for rendering web content across Apple's ecosystem. The flaw manifests as a heap-based buffer overflow or memory corruption issue that can be triggered through maliciously crafted web content, making it particularly dangerous as it can be exploited remotely without requiring any user interaction beyond visiting a compromised website. The vulnerability's classification aligns with CWE-121, heap-based buffer overflow, and CWE-125, out-of-bounds read, which are fundamental memory safety issues that have historically led to remote code execution exploits. According to ATT&CK framework, this vulnerability maps to T1203, Exploitation for Client Execution, and T1059, Command and Scripting Interpreter, as it enables attackers to execute arbitrary code on victim devices through web-based attack vectors.
The technical nature of this vulnerability stems from improper input validation and memory management within WebKit's JavaScript engine and HTML parsing components. Attackers can craft malicious web pages containing specially formatted content that, when rendered by the affected browsers, triggers memory corruption in the WebKit process. This memory corruption can lead to two primary outcomes: remote code execution allowing attackers to gain full control over the affected device, or denial of service through application crashes that disrupt normal user operations. The vulnerability's exploitability is enhanced by the fact that it operates at the browser engine level, meaning that successful exploitation can bypass many traditional security boundaries and access sensitive system resources. The memory corruption typically occurs when the WebKit engine processes malformed JavaScript or HTML elements that exceed allocated memory buffers, causing the application to crash or potentially allowing attackers to inject and execute malicious code within the browser's memory space.
The operational impact of CVE-2016-7640 extends far beyond simple browser functionality as it affects the entire Apple ecosystem including mobile devices, desktop computers, and cloud services. Users visiting compromised websites or clicking on malicious links could unknowingly become victims of attacks that compromise their devices, potentially leading to data theft, privacy violations, or full system compromise. The vulnerability's widespread impact across multiple Apple products makes it particularly concerning for enterprise environments where Apple devices are prevalent, as a single compromised device could serve as an entry point for broader network infiltration. Organizations relying on Apple's ecosystem for business operations face significant risk exposure, as the vulnerability could be leveraged for advanced persistent threats or targeted attacks against specific user groups. The memory corruption nature of the flaw means that even if an attacker cannot immediately execute code, they can potentially cause repeated application crashes that degrade system performance and availability, creating a denial of service scenario that impacts productivity.
Mitigation strategies for CVE-2016-7640 primarily focus on immediate patching and system updates across all affected Apple products. Organizations should prioritize updating iOS to version 10.2 or later, Safari to version 10.0.2 or later, iCloud to version 6.1 or later, and iTunes to version 12.5.4 or later. Network administrators should implement web filtering solutions and browser security controls to prevent access to known malicious domains while maintaining monitoring for suspicious traffic patterns. Security teams should also consider implementing sandboxing measures for web browsing activities and establishing incident response procedures specifically designed to handle potential exploitation attempts. Additional protective measures include disabling JavaScript in web browsers when not required, implementing strict content security policies, and conducting regular vulnerability assessments of Apple devices within the organization. The vulnerability's remediation aligns with industry best practices for patch management and vulnerability remediation, following the principle of least privilege and defense in depth strategies. Organizations should also consider implementing network segmentation to limit the potential impact of successful exploitation and maintain detailed logging of web browsing activities for forensic analysis purposes.