CVE-2011-2599 in Chrome
Summary
by MITRE
Google Chrome 11 does not block use of a cross-domain image as a WebGL texture, which allows remote attackers to obtain approximate copies of arbitrary images via a timing attack involving a crafted WebGL fragment shader.
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Analysis
by VulDB Data Team • 02/10/2019
The vulnerability identified as CVE-2011-2599 represents a significant security flaw in Google Chrome version 11 that undermines the browser's cross-origin security restrictions within the WebGL graphics API. This issue stems from the browser's failure to properly enforce the same-origin policy when processing cross-domain images as WebGL textures, creating an avenue for malicious actors to bypass fundamental web security mechanisms. The vulnerability specifically affects the WebGL rendering context where images loaded from different domains can be utilized as texture sources without appropriate security validation.
The technical implementation of this vulnerability exploits the timing characteristics of WebGL fragment shaders to perform covert information extraction. Attackers can craft malicious WebGL fragment shaders that analyze the rendering performance characteristics of different image textures, particularly focusing on the time required to sample pixel data from textures. This timing-based approach enables the construction of approximate reconstructions of arbitrary images from cross-domain sources, effectively circumventing the browser's security model that should prevent such unauthorized access patterns. The flaw operates at the intersection of graphics processing and security enforcement, leveraging the parallel processing capabilities of WebGL to create timing channels that leak information about protected resources.
The operational impact of CVE-2011-2599 extends beyond simple information disclosure, as it represents a sophisticated attack vector that can be weaponized to reconstruct sensitive visual data. This vulnerability allows remote attackers to perform reconnaissance activities by gradually building approximate copies of images from different origins, potentially including user interface elements, private documents, or other sensitive visual content. The attack requires the victim to visit a malicious website that loads the crafted WebGL content, making it particularly dangerous in phishing scenarios or when users visit compromised websites. The vulnerability demonstrates the complexity of securing modern web APIs where graphics processing capabilities can be leveraged for unintended information leakage.
This security weakness aligns with CWE-200, which addresses "Information Exposure," and represents a specific instance of information disclosure through timing attacks. The vulnerability also maps to ATT&CK technique T1059.007, "Command and Scripting Interpreter: JavaScript," as the attack requires JavaScript execution within the browser context to construct the malicious WebGL shaders. Additionally, it relates to T1566.001, "Social Engineering: Spearphishing Attachment," since the attack typically requires user interaction with malicious content. The flaw underscores the importance of proper sandboxing and security boundary enforcement in modern browser architectures, particularly when integrating advanced graphics APIs like WebGL that operate with direct hardware access capabilities.
The mitigation strategies for CVE-2011-2599 involve implementing proper cross-origin resource validation within WebGL implementations and strengthening the timing attack resistance mechanisms. Browser vendors should enforce stricter policies that prevent cross-domain images from being used as WebGL textures without explicit user consent or appropriate security headers. The fix typically requires updating the WebGL specification implementation to properly validate texture sources and ensure that timing-based information leakage cannot occur. Users should maintain updated browser versions and avoid visiting untrusted websites that may attempt to exploit such vulnerabilities. Organizations should also implement security monitoring to detect potential exploitation attempts through unusual WebGL activity patterns.