CVE-2013-6657 in Chrome
Summary
by MITRE
core/html/parser/XSSAuditor.cpp in the XSS auditor in Blink, as used in Google Chrome before 33.0.1750.117, inserts the about:blank URL during certain blocking of FORM elements within HTTP requests, which allows remote attackers to bypass the Same Origin Policy and obtain sensitive information via unspecified vectors.
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Analysis
by VulDB Data Team • 06/09/2021
The vulnerability described in CVE-2013-6657 resides within the XSS auditor implementation of Blink engine, which serves as the rendering engine for Google Chrome browser. This flaw specifically affects versions prior to 33.0.1750.117 and represents a critical security issue that undermines fundamental web security mechanisms. The vulnerability manifests in the core/html/parser/XSSAuditor.cpp component where the XSS protection system fails to properly handle certain FORM element blocking scenarios, creating an unexpected behavior that can be exploited by malicious actors.
The technical flaw occurs when the XSS auditor blocks FORM elements within HTTP requests and subsequently inserts the about:blank URL into the page context. This insertion creates an unexpected navigation or resource loading scenario that bypasses the same origin policy enforcement mechanisms. The same origin policy is a fundamental security model in web browsers that prevents scripts from one origin from accessing resources from another origin, thereby protecting users from cross-site scripting attacks and data theft. When this policy is circumvented through the about:blank URL insertion, attackers can potentially access sensitive information that should otherwise be restricted.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to exploit the browser's security model in ways that were not intended by the design. The unspecified vectors mentioned in the description suggest that multiple attack scenarios may be possible, potentially allowing attackers to access cookies, local storage, or other sensitive data that should be protected by the same origin policy. This type of vulnerability is particularly dangerous because it operates at the browser engine level, affecting all web applications running within the affected browser version.
This vulnerability aligns with CWE-200, which addresses the improper handling of information exposure, and relates to the broader category of privilege escalation and access control bypass issues. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and information gathering, specifically targeting the browser's security boundaries. The flaw demonstrates how seemingly minor implementation details in security systems can create significant vulnerabilities that undermine core web security principles. Organizations should prioritize updating to patched versions of Chrome and implement additional monitoring to detect potential exploitation attempts, as this vulnerability represents a sophisticated bypass of browser security controls that could be leveraged for advanced persistent threats.
The remediation approach involves updating to Chrome version 33.0.1750.117 or later, where the XSS auditor has been properly implemented to prevent the insertion of about:blank URLs during FORM element blocking. Security teams should also consider implementing additional web application firewalls and monitoring solutions that can detect anomalous navigation patterns or resource loading behaviors that might indicate exploitation attempts. Organizations maintaining older browser versions should consider implementing network-level protections and user education about avoiding suspicious websites that might attempt to leverage this vulnerability.