CVE-2024-0749 in Thunderbird
Summary
by MITRE • 01/23/2024
A phishing site could have repurposed an `about:` dialog to show phishing content with an incorrect origin in the address bar. This vulnerability affects Firefox < 122, Firefox ESR < 115.7, and Thunderbird < 115.7.
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Analysis
by VulDB Data Team • 06/19/2025
This vulnerability represents a significant browser security flaw that exploits the handling of about: dialogs in Mozilla Firefox and Thunderbird applications. The issue stems from how these browsers manage the display of about: URLs within dialog interfaces, creating a potential attack vector for malicious actors to deceive users through visual spoofing techniques. The vulnerability specifically targets the origin display mechanism in the address bar, which is a critical component of web browser security and user trust verification systems.
The technical implementation of this flaw allows attackers to manipulate about: dialogs to present misleading content while maintaining an incorrect origin indicator in the address bar. This occurs because the browser fails to properly validate or sanitize the origin information when displaying these specialized dialogs, creating a scenario where phishing content can appear to originate from legitimate sources. The vulnerability affects the core browser security model by undermining the user's ability to verify the true origin of displayed content through the address bar mechanism.
From an operational perspective, this vulnerability enables sophisticated phishing attacks that can bypass traditional security measures. Attackers can craft malicious websites that leverage this flaw to display deceptive content while maintaining the illusion of legitimate origins, making it significantly more difficult for users to identify fraudulent sites. The impact extends beyond simple phishing attempts as it undermines fundamental browser security assumptions about origin verification and user interface trust indicators. This vulnerability particularly affects users of older browser versions where the security model has not been updated to properly handle about: dialog origin validation.
The security implications of this vulnerability align with common weakness enumerations identified in CWE-601, which addresses URL redirect vulnerabilities and the improper handling of origin information in web applications. This flaw also maps to ATT&CK technique T1566, which covers phishing tactics and the use of deceptive user interfaces to gain unauthorized access. The vulnerability demonstrates how seemingly minor interface handling issues can create significant security risks when they affect core trust mechanisms within browser applications.
Mitigation strategies should focus on immediate application of security patches to all affected versions of Firefox, Thunderbird, and Firefox ESR. Organizations should implement browser hardening measures including disabling or restricting about: dialog functionality where possible, and establishing robust user education programs about recognizing phishing attempts. Network-level protections such as content filtering and security scanning tools should be deployed to detect and block suspicious about: dialog usage patterns. Additionally, administrators should consider implementing browser security policies that enforce stricter origin validation and display controls to prevent similar vulnerabilities from being exploited in the future.