CVE-2015-1254 in Chrome
Summary
by MITRE
core/dom/Document.cpp in Blink, as used in Google Chrome before 43.0.2357.65, enables the inheritance of the designMode attribute, which allows remote attackers to bypass the Same Origin Policy by leveraging the availability of editing.
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Analysis
by VulDB Data Team • 05/19/2022
The vulnerability described in CVE-2015-1254 resides within the Blink rendering engine component of Google Chrome, specifically in the Document.cpp file that manages document objects and their attributes. This flaw represents a significant security weakness that directly impacts the browser's ability to enforce the Same Origin Policy, which is a fundamental security mechanism designed to prevent unauthorized access to resources across different origins. The vulnerability affects Chrome versions prior to 43.0.2357.65, making it a critical issue that required immediate attention from users and security professionals.
The technical flaw involves the improper handling of the designMode attribute within the Blink engine's document object model. DesignMode is a feature that enables or disables the editing capabilities of a document, typically used for rich text editing in web applications. However, the vulnerability allows remote attackers to manipulate this attribute in a way that creates unexpected inheritance behavior, enabling unauthorized access to document content that should be restricted by the Same Origin Policy. This inheritance mechanism effectively bypasses the security boundaries that normally prevent scripts from one origin from accessing or modifying content from another origin.
The operational impact of this vulnerability is substantial as it provides attackers with the ability to perform cross-origin data exfiltration and manipulation attacks. When an attacker can leverage this flaw, they can potentially access sensitive information from other domains, inject malicious content, or modify document structures in ways that would normally be prohibited. The vulnerability particularly affects web applications that rely on the designMode attribute for content editing, as it allows attackers to exploit the editing capabilities across different origins. This creates a dangerous situation where a malicious actor could gain unauthorized access to documents or content that should remain protected by the browser's security model.
The vulnerability aligns with CWE-284, which deals with improper access control, and demonstrates how flaws in attribute inheritance mechanisms can lead to privilege escalation and policy bypass scenarios. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and defense evasion, as it allows attackers to circumvent security controls that should prevent cross-origin operations. The flaw essentially creates a backdoor through which malicious actors can access document objects and their content without proper authorization. Organizations and users were strongly advised to update to Chrome version 43.0.2357.65 or later, as this update included patches that properly addressed the attribute inheritance behavior and restored the intended Same Origin Policy enforcement. The fix implemented by Google involved modifying the document attribute handling logic to prevent unintended inheritance of designMode settings across different origins, thereby restoring proper security boundaries within the browser's document management system.