CVE-2016-4588 in tvOS
Summary
by MITRE
WebKit in Apple tvOS before 9.2.2 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/04/2019
The vulnerability identified as CVE-2016-4588 represents a critical memory corruption flaw within the WebKit rendering engine component of Apple tvOS versions prior to 9.2.2. This issue resides in the browser engine that processes web content on Apple's television operating system, creating a pathway for remote attackers to potentially gain unauthorized execution privileges or disrupt system functionality. The vulnerability stems from improper handling of memory structures when processing specially crafted web content, which can lead to unpredictable behavior and system instability. The WebKit engine serves as the foundation for web browsing capabilities on tvOS, making this flaw particularly concerning given the widespread use of web-based applications and services on Apple TV devices.
The technical nature of this vulnerability falls under memory corruption patterns that are commonly categorized as CWE-121, heap-based buffer overflow, or similar memory management flaws that occur when applications fail to properly validate or constrain memory operations. Attackers can exploit this weakness by hosting malicious web content that, when loaded through the tvOS web browser, triggers specific code paths within WebKit that lead to memory corruption. The flaw likely manifests during the parsing or rendering of complex web elements such as JavaScript objects, HTML structures, or multimedia content that exceed normal memory boundaries. This type of vulnerability is particularly dangerous because it can be triggered remotely through standard web browsing activities without requiring any special privileges or user interaction beyond visiting a compromised website.
The operational impact of CVE-2016-4588 extends beyond simple denial of service scenarios to encompass full system compromise capabilities that align with ATT&CK technique T1203 for Exploitation for Client Execution. Remote attackers can leverage this vulnerability to execute arbitrary code on affected tvOS devices, potentially gaining persistent access to the television system and its associated network resources. This compromise could enable attackers to install malicious applications, access user data, monitor network traffic, or use the compromised device as a pivot point for attacking other networked systems. The vulnerability affects a broad range of Apple TV hardware including the Apple TV 2nd generation through Apple TV 4th generation models, creating widespread exposure across the user base. The remote nature of the attack means that users could be compromised simply by visiting malicious websites, making this vulnerability particularly insidious in its attack surface.
Mitigation strategies for CVE-2016-4588 primarily focus on applying the official Apple security updates that address the memory corruption issue within WebKit. Users should immediately update their tvOS installations to version 9.2.2 or later, which contains the necessary patches to prevent exploitation of this vulnerability. System administrators should implement network monitoring to detect potential exploitation attempts and consider deploying web filtering solutions to block access to known malicious domains. The vulnerability also highlights the importance of maintaining up-to-date security patches for all operating system components, particularly those that handle network-based input processing. Organizations should also consider implementing network segmentation to limit the potential impact of successful exploitation and establish incident response procedures for detecting and responding to potential compromise of tvOS devices. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping their devices updated with the latest security patches.