CVE-2018-6077 in Chrome
Summary
by MITRE
Displacement map filters being applied to cross-origin images in Blink SVG rendering in Google Chrome prior to 65.0.3325.146 allowed a remote attacker to leak cross-origin data via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/06/2023
The vulnerability identified as CVE-2018-6077 represents a critical security flaw in the Blink rendering engine's handling of SVG displacement map filters when applied to cross-origin images. This issue affected Google Chrome versions prior to 65.0.3325.146 and exploited a fundamental weakness in the browser's cross-origin resource sharing (CORS) protection mechanisms. The vulnerability specifically targeted the SVG filter processing pipeline where displacement maps are used to manipulate image coordinates, creating a potential vector for information disclosure attacks.
The technical implementation of this vulnerability stems from the improper handling of cross-origin image data within SVG filter operations. When a displacement map filter is applied to an image, the filter processes pixel data to determine how to transform the image coordinates. In the affected Chrome versions, the rendering engine failed to properly validate or sanitize cross-origin image data before applying these filters, allowing malicious actors to craft HTML pages that could extract pixel information from images loaded from different origins. This flaw essentially bypassed the same-origin policy enforcement mechanisms that are fundamental to web security models.
The operational impact of this vulnerability extends beyond simple data leakage, creating potential pathways for more sophisticated attacks. An attacker could construct malicious web pages that would silently extract visual information from cross-origin resources, potentially including sensitive data embedded within images or visual artifacts that reveal information about the underlying content. The vulnerability operates at the SVG rendering level, making it particularly dangerous because SVG filters are commonly used in web applications for graphical effects and data visualization. This attack vector could be exploited in conjunction with other techniques to build more comprehensive reconnaissance capabilities.
This vulnerability maps directly to CWE-200 (Information Exposure) and CWE-123 (Bind to Well-Known Port) categories within the CWE taxonomy, reflecting the information disclosure nature of the flaw and its exploitation through well-known rendering mechanisms. From the MITRE ATT&CK framework perspective, this represents a technique for credential access through information discovery, specifically targeting the T1082 (System Information Discovery) and T1046 (Network Service Scanning) domains. The attack chain typically involves initial access through a malicious web page, followed by the exploitation of the rendering engine vulnerability to extract cross-origin data. The remediation approach required updating Chrome to version 65.0.3325.146 or later, which implemented proper cross-origin validation within SVG filter processing. Organizations should ensure comprehensive browser updates and consider implementing additional network-level protections such as content security policies that restrict cross-origin resource usage in SVG contexts to prevent exploitation of similar rendering vulnerabilities.