CVE-2005-0402 in Firefox
Summary
by MITRE
Firefox before 1.0.2 allows remote attackers to execute arbitrary code by tricking a user into saving a page as a Firefox sidebar panel, then using the sidebar panel to inject Javascript into a privileged page.
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Analysis
by VulDB Data Team • 07/05/2025
The vulnerability described in CVE-2005-0402 represents a critical security flaw in the Firefox web browser that existed prior to version 1.0.2. This issue stems from a dangerous privilege escalation mechanism that allows remote attackers to execute arbitrary code on vulnerable systems. The vulnerability specifically exploits the Firefox sidebar functionality, which was designed to provide users with convenient access to frequently visited websites and web applications. The flaw occurs when users are tricked into saving a malicious web page as a Firefox sidebar panel, a seemingly benign action that becomes a vector for sophisticated attacks.
The technical implementation of this vulnerability involves the manipulation of Firefox's security model, particularly around the handling of privileged pages and the sidebar panel functionality. When a user saves a page as a sidebar panel, Firefox creates a special context that should normally maintain proper security boundaries between user-accessible content and privileged browser components. However, the vulnerability allows attackers to inject javascript code into this privileged context through the sidebar panel, effectively bypassing the normal security restrictions that should prevent untrusted code from executing with elevated privileges. This represents a classic case of insufficient privilege separation and inadequate input validation in the browser's sidebar panel handling mechanism.
The operational impact of this vulnerability is severe as it enables remote code execution with the privileges of the browser process itself. Attackers can leverage this flaw to gain complete control over the victim's system, potentially leading to data theft, system compromise, or further lateral movement within a network. The attack requires social engineering to trick users into performing the specific action of saving a malicious page as a sidebar panel, but once successful, the consequences are catastrophic. The vulnerability affects all versions of Firefox prior to 1.0.2 and represents a significant weakness in the browser's security architecture that could be exploited by attackers with minimal technical expertise.
Security researchers have classified this vulnerability according to CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" as the underlying cause of the issue. The vulnerability also aligns with ATT&CK technique T1059.007, "Command and Scripting Interpreter: JavaScript," which describes how attackers can use JavaScript to execute malicious code. Organizations affected by this vulnerability should immediately upgrade to Firefox version 1.0.2 or later, which includes patches addressing the sidebar panel privilege escalation issue. Additional mitigations include implementing strict browser security policies, disabling sidebar functionality where possible, and educating users about the dangers of saving unknown content as sidebar panels. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date software and the potential risks associated with browser extensions and sidebar functionality in web applications.