CVE-2016-4728 in tvOS
Summary
by MITRE
WebKit in Apple iOS before 10, tvOS before 10, iTunes before 12.5.1 on Windows, and Safari before 10 mishandles error prototypes, which allows remote attackers to execute arbitrary code via a crafted web site.
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Analysis
by VulDB Data Team • 09/21/2022
The vulnerability identified as CVE-2016-4728 represents a critical flaw in Apple's WebKit rendering engine that affected multiple platforms including iOS, tvOS, iTunes, and Safari versions prior to their respective updates. This issue stems from improper handling of error prototypes within the WebKit JavaScript engine, creating a significant security risk that could be exploited by remote attackers to execute arbitrary code on affected systems. The flaw exists in the way WebKit processes error objects and their prototype chains, allowing malicious actors to manipulate these objects in ways that bypass normal security restrictions and execute unauthorized commands.
The technical implementation of this vulnerability involves the manipulation of JavaScript error objects and their prototype properties within the WebKit engine. When WebKit encounters certain error conditions, it fails to properly validate or sanitize the prototype chain of error objects, creating opportunities for attackers to craft malicious web pages that exploit this weakness. This behavior aligns with CWE-472, which specifically addresses "External Control of System or Daemon" where external input is used to control system behavior, and can be categorized under the broader category of prototype pollution vulnerabilities. Attackers can leverage this flaw by constructing web pages that manipulate error prototype objects to achieve code execution, often through techniques involving object manipulation and prototype chain poisoning that are commonly documented in exploit development literature.
The operational impact of CVE-2016-4728 is severe as it enables remote code execution without requiring user interaction beyond visiting a malicious website, making it particularly dangerous in phishing campaigns and drive-by download scenarios. This vulnerability affects a broad range of Apple products and services, including mobile devices, desktop applications, and web browsers, creating widespread exposure across Apple's ecosystem. The exploitability of this vulnerability is enhanced by the fact that it can be triggered through standard web browsing activities, meaning users could be compromised simply by visiting a malicious site or viewing a crafted email with embedded web content. The vulnerability's impact extends beyond individual user devices to potentially compromise enterprise networks and cloud services that rely on Apple's web technologies.
Mitigation strategies for CVE-2016-4728 primarily focus on immediate platform updates and patches provided by Apple to address the underlying WebKit flaw. Organizations should prioritize updating all affected Apple products to the latest versions, specifically iOS 10, tvOS 10, iTunes 12.5.1, and Safari 10, which contain the necessary security fixes. Network administrators should implement web filtering solutions and browser security controls to block access to known malicious domains while monitoring for suspicious web traffic patterns. Additionally, security teams should conduct thorough vulnerability assessments to identify any systems that may still be running affected versions of Apple software, particularly in enterprise environments where device management and patch deployment cycles may be slower. The ATT&CK framework categorizes this vulnerability under T1059 for Command and Scripting Interpreter and T1203 for Exploitation for Client Execution, emphasizing the need for both endpoint protection and network-based security controls to prevent exploitation. Organizations should also consider implementing browser hardening measures and restricting JavaScript execution in enterprise environments to reduce the attack surface and limit potential exploitation success.