CVE-2016-4585 in tvOS
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the WebKit Page Loading implementation in Apple iOS before 9.3.3, Safari before 9.1.2, and tvOS before 9.2.2 allows remote attackers to inject arbitrary web script or HTML via an HTTP response specifying redirection that is mishandled by Safari.
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Analysis
by VulDB Data Team • 09/06/2022
This cross-site scripting vulnerability exists within Apple's WebKit implementation and affects multiple Apple operating systems including iOS versions prior to 9.3.3 Safari versions before 9.1.2 and tvOS versions before 9.2.2. The flaw specifically occurs in how the web browser handles HTTP response redirections that contain malicious content. Attackers can exploit this weakness by crafting HTTP responses that specify redirections containing arbitrary web script or HTML code which the Safari browser fails to properly sanitize or validate before executing. This vulnerability falls under the CWE-79 category of Cross-Site Scripting and represents a classic case of improper input validation where user-controllable data enters the application through HTTP response headers without adequate sanitization.
The technical mechanism of exploitation involves the manipulation of HTTP redirect responses that contain malicious payloads within their location headers or related redirect parameters. When Safari processes these malformed redirect responses it incorrectly interprets the injected script or HTML content as legitimate browser behavior rather than malicious input. This occurs because the browser's page loading implementation does not adequately validate or escape the content of redirect specifications before processing them. The vulnerability is particularly dangerous because it can be triggered through standard web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website.
The operational impact of this vulnerability extends beyond simple script execution to potentially enable more sophisticated attacks including session hijacking credential theft and phishing operations. Attackers could redirect users to malicious sites that appear legitimate while simultaneously executing malicious scripts that capture user input or steal session cookies. The vulnerability affects all web content delivered through Safari browsers on the affected Apple platforms making it a widespread concern for users who browse the internet using these operating systems. This weakness directly impacts the browser's security model by allowing remote code execution through the standard HTTP redirection mechanism which is fundamental to web navigation.
Organizations and users should immediately apply the security updates provided by Apple to mitigate this vulnerability. The patches released in iOS 9.3.3 Safari 9.1.2 and tvOS 9.2.2 address the underlying issue by implementing proper input validation and sanitization of HTTP redirect responses. Security teams should also consider implementing web application firewalls and content security policies that can detect and block suspicious redirect patterns. Additionally the vulnerability highlights the importance of proper input validation in web browser implementations and aligns with ATT&CK technique T1059.001 for command and script injection. Organizations should conduct security assessments to ensure all affected Apple devices are updated and monitor for any exploitation attempts targeting this specific vulnerability. The remediation process should include verifying that the security patches have been successfully applied and testing browser functionality to ensure proper redirect handling without introducing regressions in legitimate web browsing operations.