CVE-2004-1380 in Avant
Summary
by MITRE
Firefox before 1.0 and Mozilla before 1.7.5 allows inactive (background) tabs to launch dialog boxes, which can allow remote attackers to spoof the dialog boxes from web sites in other windows and facilitate phishing attacks, aka the "Dialog Box Spoofing Vulnerability."
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Analysis
by VulDB Data Team • 09/28/2025
The vulnerability identified as CVE-2004-1380 represents a significant security flaw in web browsers that persisted across multiple versions of Firefox and Mozilla applications. This issue specifically affects browser implementations where inactive tabs can unexpectedly generate dialog boxes, creating a critical window for malicious actors to exploit user trust and system security. The flaw fundamentally undermines the expected behavior of modern web browsers where background tabs should remain passive and not interfere with active user sessions.
The technical implementation of this vulnerability stems from improper handling of dialog box generation within the browser's tab management system. When a web page in an inactive tab attempts to display a dialog box, the browser's user interface fails to properly restrict or validate the source of these dialog boxes. This allows malicious websites to craft dialog boxes that appear to originate from legitimate domains or even the current active window, creating a deceptive user experience that bypasses normal security boundaries. The vulnerability specifically exploits the lack of proper isolation between active and inactive tab contexts, enabling cross-tab dialog box manipulation.
The operational impact of this vulnerability extends beyond simple user inconvenience to create serious security risks that can facilitate sophisticated phishing attacks. Attackers can leverage this flaw to make malicious dialog boxes appear as if they originate from trusted websites or system components, thereby deceiving users into providing sensitive information or performing actions they would not normally consent to. This spoofing capability directly undermines user confidence in browser security and creates opportunities for credential theft, financial fraud, and other malicious activities that rely on social engineering. The vulnerability is particularly dangerous because it operates silently in the background without user awareness.
The security implications of this vulnerability align with several established threat frameworks including the attack pattern taxonomy where this represents a form of user interface deception. From a common weakness enumeration perspective, this vulnerability maps to CWE-611 which deals with improper access control in web applications. The flaw demonstrates how inadequate separation of concerns in browser architecture can create attack vectors that bypass traditional security controls. Organizations and users affected by this vulnerability faced increased risk of successful phishing campaigns and social engineering attacks that exploited the browser's failure to properly isolate tab contexts.
Mitigation strategies for this vulnerability required immediate browser updates and patches that addressed the dialog box generation logic within tab management systems. Users needed to upgrade to Firefox 1.0 or Mozilla 1.7.5 and later versions to receive the necessary security fixes. Browser vendors implemented stricter validation of dialog box sources and enhanced isolation between active and inactive tab contexts. Additionally, users were advised to exercise caution when browsing and to verify the authenticity of dialog boxes before responding to them. The vulnerability highlighted the importance of maintaining current browser versions and implementing layered security approaches to protect against such sophisticated attack vectors that exploit browser implementation details rather than network-level vulnerabilities.