CVE-2016-4657 in iOS
Summary
by MITRE
WebKit in Apple iOS before 9.3.5 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.
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Analysis
by VulDB Data Team • 01/29/2025
The vulnerability identified as CVE-2016-4657 represents a critical memory corruption flaw within WebKit, the web rendering engine that powers Safari and other web-based applications on Apple iOS devices. This vulnerability affects iOS versions prior to 9.3.5 and exposes users to significant security risks through maliciously crafted web content. The flaw resides in how WebKit processes certain web page elements, creating opportunities for remote code execution or denial of service conditions that can be triggered simply by visiting an compromised website.
Technical analysis reveals that the vulnerability stems from improper memory management within WebKit's JavaScript engine, specifically in how it handles certain object allocations and deallocations. The flaw manifests when WebKit encounters specially crafted web content that exploits memory corruption patterns, allowing attackers to manipulate heap memory structures and potentially execute arbitrary code with the privileges of the affected application. This type of vulnerability falls under CWE-122, which describes improper restriction of operations within the bounds of a memory buffer, and aligns with ATT&CK technique T1059.007 for scripting languages and T1203 for exploitation for execution.
The operational impact of this vulnerability extends beyond simple remote code execution, as it can also enable denial of service conditions that disrupt normal device functionality. Attackers can craft web pages that trigger memory corruption during page rendering or JavaScript execution, potentially causing system crashes or complete device instability. The remote nature of the attack means users need only visit a malicious website to be compromised, making this vulnerability particularly dangerous in mobile environments where users frequently browse the web. This weakness affects all iOS devices running versions prior to 9.3.5, including iPhones, iPads, and iPod touches, creating widespread exposure across Apple's mobile ecosystem.
Mitigation strategies for CVE-2016-4657 primarily focus on immediate system updates and security hardening measures. Apple addressed this vulnerability through iOS 9.3.5, which included patches to WebKit's memory management routines and improved bounds checking mechanisms. Organizations should implement comprehensive patch management policies ensuring all iOS devices receive the latest security updates promptly. Additionally, network administrators can deploy web filtering solutions and browser security extensions to block access to known malicious domains. The vulnerability demonstrates the importance of maintaining up-to-date software and highlights the critical need for mobile device management programs that can quickly deploy security patches across enterprise device fleets. Users should also exercise caution when visiting unfamiliar websites and maintain awareness of social engineering tactics that might lead to malicious web content exposure.