CVE-2016-4587 in tvOS
Summary
by MITRE
WebKit in Apple iOS before 9.3.3 and tvOS before 9.2.2 allows remote attackers to obtain sensitive information from uninitialized process memory via a crafted web site.
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Analysis
by VulDB Data Team • 09/06/2022
This vulnerability resides in the WebKit rendering engine component of Apple's iOS and tvOS operating systems, specifically affecting versions prior to 9.3.3 for iOS and 9.2.2 for tvOS. The flaw represents a classic information disclosure vulnerability that occurs when web content interacts with uninitialized memory segments within the browser engine. Attackers can craft malicious websites that trigger memory access patterns which reveal sensitive data previously stored in memory locations that were never properly initialized or cleared. This type of vulnerability falls under the CWE-248 category of "Uncaught Exception" and represents a fundamental memory management issue where the system fails to properly sanitize memory before exposing it to web applications. The vulnerability demonstrates how web-based attacks can leverage browser engine weaknesses to access system resources that should remain isolated from web content execution contexts.
The technical exploitation of this vulnerability involves crafting web content that forces WebKit to access memory regions containing sensitive information from previous processes or operations. When a user visits a malicious website, the browser engine's memory management routines fail to properly initialize memory segments before they are accessed, allowing attackers to read data that may contain passwords, session tokens, personal information, or other sensitive data that was previously stored in those memory locations. This memory disclosure occurs through JavaScript or other web technologies that can trigger memory access patterns, making it particularly dangerous as it can be exploited through standard web browsing activities without requiring any special privileges or user interaction beyond visiting the malicious site. The vulnerability is classified as a memory safety issue that represents a breakdown in the principle of least privilege within the browser's memory management architecture.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially enable more sophisticated attacks by providing attackers with sensitive data that can be used for further exploitation. An attacker who successfully exploits this vulnerability could obtain session cookies, authentication tokens, or other credentials that would allow them to impersonate users or gain unauthorized access to services. This type of vulnerability can be particularly dangerous in enterprise environments where users may access sensitive corporate data through web browsers, as the disclosed information could include internal network details, user credentials, or other valuable intelligence. The vulnerability represents a significant risk to user privacy and system security, as it allows remote attackers to gain access to data that should remain protected within the system's memory boundaries. According to ATT&CK framework, this vulnerability maps to techniques involving credential access and defense evasion, as it can be used to gather information that facilitates further compromise of the system.
Mitigation strategies for this vulnerability primarily involve updating to the patched versions of iOS and tvOS where Apple has implemented proper memory initialization routines and improved memory management within the WebKit engine. Organizations should prioritize immediate deployment of the security updates and implement network monitoring to detect potential exploitation attempts. Additional protective measures include implementing web content filtering solutions that can block known malicious domains, deploying browser hardening configurations that limit memory access patterns, and conducting regular security assessments to identify potential exposure to similar vulnerabilities. The vulnerability highlights the importance of proper memory management practices in browser engines and demonstrates how seemingly simple memory initialization issues can create significant security risks. Security teams should also consider implementing network segmentation and access controls to limit the potential impact if exploitation occurs, as the disclosed information could be used to facilitate more advanced attacks within the compromised environment.