CVE-2016-5192 in Chrome
Summary
by MITRE
Blink in Google Chrome prior to 54.0.2840.59 for Windows missed a CORS check on redirect in TextTrackLoader, which allowed a remote attacker to bypass cross-origin restrictions via crafted HTML pages.
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Analysis
by VulDB Data Team • 10/12/2022
The vulnerability identified as CVE-2016-5192 resides within the Blink rendering engine of Google Chrome versions prior to 54.0.2840.59 on Windows platforms. This issue represents a critical security flaw that specifically targets the Cross-Origin Resource Sharing (CORS) validation mechanisms implemented within the browser's text track loading functionality. The vulnerability manifests through the TextTrackLoader component which is responsible for handling WebVTT (Web Video Text Tracks) files that contain subtitles, captions, and other text-based media metadata. When processing redirects during text track loading operations, the browser failed to properly enforce CORS policies, creating a pathway for malicious actors to circumvent intended security boundaries.
The technical exploitation of this vulnerability occurs through carefully crafted HTML pages that leverage the improper redirect handling within TextTrackLoader. When Chrome encounters a text track resource that requires redirection, the missing CORS check allows attackers to redirect requests to cross-origin resources that would normally be restricted. This flaw operates at the intersection of web security policies and browser implementation, where the expected behavior of enforcing CORS restrictions during redirect operations was not properly maintained. The vulnerability specifically affects the validation of origin domains when processing text track resources, enabling attackers to access content that should be restricted based on cross-origin policies. This represents a classic case of insufficient input validation and security boundary enforcement within the browser's resource loading pipeline.
The operational impact of this vulnerability extends beyond simple information disclosure, as it allows remote attackers to potentially access sensitive content that should be protected by CORS policies. Attackers can construct malicious web pages that load text tracks from different origins and leverage the redirect bypass to access resources that would normally be blocked. This could enable the retrieval of private content, user data, or other sensitive information that should be restricted by origin policies. The vulnerability particularly affects scenarios where text track resources are loaded from external domains, making it applicable to various multimedia applications and websites that utilize WebVTT files. The risk is amplified in environments where users might encounter crafted content through social engineering or compromised websites, as the exploitation requires no user interaction beyond visiting the malicious page.
Mitigation strategies for CVE-2016-5192 primarily involve updating to Google Chrome version 54.0.2840.59 or later, which implements the necessary CORS validation checks during redirect operations in TextTrackLoader. System administrators should prioritize patch management to ensure all affected Chrome installations are updated promptly, as this vulnerability represents a significant risk to web application security. Additional protective measures include implementing Content Security Policy headers that restrict text track loading from untrusted sources, monitoring for suspicious text track resource loading patterns, and conducting regular security assessments of web applications that utilize WebVTT functionality. Organizations should also consider deploying web application firewalls that can detect and block suspicious redirect patterns, and maintain awareness of related vulnerabilities in browser components that handle resource loading and CORS validation. This vulnerability aligns with CWE-652 (Improper Neutralization of Data within a Security Boundary) and maps to ATT&CK technique T1059.001 (Command and Scripting Interpreter: PowerShell) through potential post-exploitation activities that might involve manipulating web resources. The remediation process should include comprehensive testing of updated browser versions to ensure that CORS policies function correctly across all text track loading scenarios, particularly those involving redirects and cross-origin resource access.