CVE-2016-7635 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 • 08/25/2025
The vulnerability identified as CVE-2016-7635 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 foundational browser engine for Apple's web browsing capabilities across its ecosystem. The flaw manifests as a remote code execution vulnerability that enables attackers to craft malicious websites capable of exploiting memory corruption issues within the WebKit engine, potentially leading to arbitrary code execution or application crashes.
The technical nature of this vulnerability stems from improper memory handling within the WebKit rendering engine's JavaScript engine, specifically involving the interaction between JavaScript objects and the memory management system. When users navigate to a maliciously crafted website, the WebKit engine processes the page content in a manner that triggers memory corruption, allowing attackers to manipulate memory locations and potentially execute arbitrary code with the privileges of the affected application. This type of vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of how memory safety issues in browser engines can be exploited for remote code execution. The vulnerability operates through the standard attack vector of web-based exploitation where the malicious payload is delivered through a crafted web page that leverages JavaScript and DOM manipulation techniques to trigger the memory corruption.
The operational impact of CVE-2016-7635 extends beyond simple application crashes to represent a significant security risk for users of affected Apple products. Remote attackers can leverage this vulnerability to execute arbitrary code on targeted systems without requiring any user interaction beyond visiting a malicious website, making it particularly dangerous in phishing campaigns and drive-by download scenarios. The vulnerability affects not just individual web browsing sessions but also represents a potential threat to the broader iCloud and iTunes services that rely on the WebKit engine for their web-based components. This attack surface is particularly concerning given that these applications run with elevated privileges on iOS devices and desktop systems, potentially allowing attackers to gain full system access or perform data exfiltration operations.
Security professionals should note that this vulnerability aligns with ATT&CK technique T1203, which covers exploitation for execution through web-based attacks, and demonstrates the importance of keeping web browser components updated. The remediation strategy involves immediate deployment of Apple's security updates, specifically iOS 10.2, Safari 10.0.2, iCloud 6.1, and iTunes 12.5.4, which address the memory corruption issues within the WebKit engine. Organizations should also implement network-based protections such as web application firewalls and content filtering systems to mitigate exposure while awaiting patch deployment. The vulnerability highlights the critical need for regular security patch management and the importance of monitoring for emerging threats in browser engine components, as WebKit-based vulnerabilities often represent high-value targets for advanced persistent threat actors due to their broad impact across Apple's ecosystem.