CVE-2017-7109 in tvOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11 is affected. Safari before 11 is affected. iCloud before 7.0 on Windows is affected. iTunes before 12.7 on Windows is affected. tvOS before 11 is affected. The issue involves the "WebKit" component. A cross-site scripting (XSS) vulnerability allows remote attackers to inject arbitrary web script or HTML via crafted web content that incorrectly interacts with the Application Cache policy.
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Analysis
by VulDB Data Team • 01/20/2021
The vulnerability identified as CVE-2017-7109 represents a significant cross-site scripting flaw within Apple's WebKit rendering engine that affected multiple Apple platforms and applications. This security weakness resides in the Application Cache policy implementation within WebKit, which is the core component responsible for rendering web content across Apple's ecosystem. The vulnerability specifically manifests when WebKit incorrectly processes crafted web content that interacts with the Application Cache policy, creating an avenue for malicious actors to execute arbitrary web scripts or HTML code within the context of affected applications. The affected software versions span across iOS before 11.0, Safari before 11.0, iCloud before version 7.0 on Windows, iTunes before version 12.7 on Windows, and tvOS before 11.0, demonstrating the widespread impact across Apple's mobile, desktop, and television operating systems.
The technical nature of this vulnerability places it squarely within the category of cross-site scripting attacks as defined by CWE-79, which specifically addresses the improper handling of input data that leads to the execution of unintended code within web browsers. The flaw occurs due to inadequate validation and sanitization of web content when the Application Cache policy is invoked, allowing attackers to craft malicious web pages that, when loaded by affected browsers, execute code with the privileges of the user's browsing session. This particular implementation of XSS stems from the improper interaction between web content and the Application Cache mechanism, which should normally provide a secure sandbox for cached resources but instead becomes a vector for code injection. The vulnerability's exploitation requires attackers to convince victims to visit malicious web pages or interact with crafted content, making it particularly dangerous in phishing scenarios or when users encounter compromised websites.
The operational impact of CVE-2017-7109 extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including but not limited to session hijacking, data theft, credential harvesting, and redirection to malicious sites. Attackers could potentially exploit this vulnerability to access sensitive user data stored in browser sessions, steal authentication tokens, or modify web page content to deceive users into revealing personal information. The widespread nature of affected platforms means that users across multiple Apple ecosystems were potentially exposed, creating a significant attack surface that could be leveraged for large-scale campaigns. This vulnerability particularly threatens users of Apple's mobile devices and desktop applications who frequently browse the web, as the attack vectors can be easily concealed within seemingly legitimate web content.
Mitigation strategies for this vulnerability require immediate patching of affected systems to update WebKit components to versions that properly validate and sanitize web content interactions with the Application Cache policy. Apple released security updates for iOS 11, Safari 11, iCloud 7.0, iTunes 12.7, and tvOS 11 that addressed this specific flaw by strengthening input validation mechanisms and correcting the improper handling of Application Cache policies. Organizations should implement comprehensive patch management procedures to ensure all affected Apple products receive timely updates, as well as consider network-level protections such as web application firewalls and content filtering solutions that can detect and block malicious web content. Security teams should also conduct user awareness training to help identify potentially malicious web content and encourage safe browsing practices, while monitoring for indicators of compromise that might suggest exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date security patches across all platforms and highlights the critical role that browser security components play in protecting users from sophisticated web-based attacks.