CVE-2004-0191 in Firefox
Summary
by MITRE
Mozilla before 1.4.2 executes Javascript events in the context of a new page while it is being loaded, allowing it to interact with the previous page (zombie document) and enable cross-domain and cross-site scripting (XSS) attacks, as demonstrated using onmousemove events.
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Analysis
by VulDB Data Team • 06/27/2019
The vulnerability described in CVE-2004-0191 represents a critical security flaw in the Mozilla browser family prior to version 1.4.2 that fundamentally compromised the isolation between web pages during navigation transitions. This issue stems from the browser's improper handling of JavaScript execution context when users navigate from one page to another, creating a dangerous scenario where scripts from the new page could interact with the previous page's document object model even while the new page was still loading. The technical implementation flaw allowed for the execution of JavaScript events in a zombie document state, where the previous page's DOM remained accessible and manipulable by the newly loaded page's scripts.
The operational impact of this vulnerability extends far beyond simple cross-site scripting capabilities, as it enabled attackers to exploit the temporal window between page transitions to execute malicious code against the previous page's content. This particular exploitation method leveraged onmousemove events to demonstrate how attackers could inject and execute arbitrary JavaScript code that would persist in the zombie document context, potentially allowing for session hijacking, credential theft, and data exfiltration. The vulnerability specifically exploited the browser's failure to properly isolate the execution environment during page load transitions, creating a persistent attack surface that could be leveraged across different domains and sites.
From a cybersecurity perspective, this vulnerability aligns with CWE-74 and CWE-79 categories related to improper neutralization of special elements in output used by a downstream component and injection flaws respectively. The attack vector specifically maps to techniques described in the MITRE ATT&CK framework under T1059.007 for JavaScript execution and T1566 for credential access through social engineering. The vulnerability demonstrates a classic case of insufficient input validation and improper state management during browser navigation operations, where the security boundary between different web contexts was not properly enforced. This flaw essentially created a persistent security gap that allowed for the exploitation of temporal inconsistencies in browser page loading behavior.
The mitigation strategies for this vulnerability required immediate browser updates to version 1.4.2 or later, which implemented proper document context isolation during page transitions. Security practitioners should have enforced strict browser version controls and implemented content security policies to prevent unauthorized script execution. Additionally, web developers needed to be aware of the risks associated with page transition events and implement proper input sanitization to prevent exploitation of similar temporal vulnerabilities in their applications. Organizations should have conducted thorough security assessments of their browser environments and implemented monitoring for suspicious JavaScript execution patterns that could indicate exploitation attempts against similar vulnerabilities.