CVE-2007-3737 in Firefox
Summary
by MITRE
Mozilla Firefox before 2.0.0.5 allows remote attackers to execute arbitrary code with chrome privileges by calling an event handler from an unspecified "element outside of a document."
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Analysis
by VulDB Data Team • 07/22/2019
This vulnerability exists in mozilla firefox versions prior to 2.0.0.5 and represents a critical privilege escalation flaw that allows remote attackers to execute arbitrary code with chrome privileges. The vulnerability stems from improper handling of event handlers when invoked from elements that exist outside of the normal document context, creating a pathway for malicious code execution. The flaw specifically occurs when an event handler is called from an unspecified element that is not part of the standard document structure, enabling attackers to bypass security restrictions that normally prevent code execution with elevated chrome privileges.
The technical implementation of this vulnerability leverages the browser's event handling mechanism to manipulate the execution context of javascript code. When firefox processes event handlers from elements outside of the document, it fails to properly validate the security context of these calls, allowing malicious code to execute with the privileges of the chrome environment rather than the restricted user context. This represents a classic sandbox escape vulnerability where the security boundaries between user-level code and privileged chrome code are improperly enforced. The vulnerability falls under the category of privilege escalation and code execution flaws, with specific implications for browser security models and the isolation between different execution contexts within web browsers.
The operational impact of this vulnerability is severe as it enables remote attackers to execute arbitrary code with elevated privileges on affected systems. Attackers can craft malicious web pages that, when loaded in vulnerable firefox versions, will trigger the exploit and allow remote code execution with chrome privileges. This means that malicious actors can potentially access sensitive system resources, modify browser functionality, or perform actions that should be restricted to the browser's privileged components. The vulnerability is particularly dangerous because it operates remotely without requiring user interaction beyond visiting a malicious website, making it an ideal candidate for drive-by download attacks and other remote exploitation techniques.
This vulnerability is classified under cwe-264 in the common weakness enumeration and relates to privilege escalation in software components. It also maps to several attack techniques in the mitre att&ck framework including privilege escalation through browser exploits and remote code execution via web applications. The exploit requires an attacker to craft a malicious webpage that specifically targets the event handler processing logic in firefox's javascript engine, leveraging the browser's failure to properly validate execution contexts. Organizations should immediately update to firefox version 2.0.0.5 or later to remediate this vulnerability, as the fix addresses the core issue of improper privilege validation when processing event handlers from external elements. Additionally, browser security teams should implement additional monitoring for unusual event handler behavior and consider implementing stricter validation of execution contexts to prevent similar issues from arising in the future.
The broader implications of this vulnerability highlight the complexity of modern browser security architectures and the challenges of maintaining proper privilege boundaries between different execution contexts. Browser vendors must continuously evaluate their security models against evolving attack techniques and ensure that all code paths properly validate security contexts before executing privileged operations. This vulnerability demonstrates that even seemingly minor flaws in event handling mechanisms can have significant security implications when they allow bypass of fundamental security boundaries. Regular security updates and comprehensive testing of browser security models are essential to protect against such vulnerabilities, as they represent the intersection of complex javascript execution environments with privileged system operations. The incident also underscores the importance of maintaining up-to-date security practices and the need for continuous monitoring of browser security implementations to identify and remediate similar issues before they can be exploited by malicious actors.