CVE-2023-5721 in Thunderbird
Summary
by MITRE • 10/25/2023
It was possible for certain browser prompts and dialogs to be activated or dismissed unintentionally by the user due to an insufficient activation-delay. This vulnerability affects Firefox < 119, Firefox ESR < 115.4, and Thunderbird < 115.4.1.
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Analysis
by VulDB Data Team • 03/06/2025
This vulnerability represents a user interface interaction flaw that exploits insufficient activation-delay mechanisms in browser prompts and dialogs. The issue stems from a design weakness in how the browser handles user input validation for interactive elements, creating opportunities for unintended system behavior. The vulnerability specifically impacts Firefox versions prior to 119, Firefox ESR versions prior to 115.4, and Thunderbird versions prior to 115.4.1, indicating a widespread client-side exposure across Mozilla's product ecosystem. The insufficient activation-delay mechanism allows for race conditions where user interactions can trigger dialog behaviors before the system has properly initialized the prompt state, leading to potential security implications through unexpected user interface manipulation.
The technical implementation of this vulnerability involves timing-sensitive user interface components that fail to properly validate interaction sequences before executing prompt activation or dismissal routines. When users interact with browser dialogs, the system should enforce a minimum delay between user input detection and actual execution of the dialog action. Without this delay, rapid successive clicks or input events can cause the system to process multiple states simultaneously, resulting in unintended activation or dismissal of security-related prompts. This flaw operates at the application layer and affects the browser's graphical user interface subsystem, making it particularly concerning for security-sensitive operations such as certificate warnings, password prompts, or permission requests. The vulnerability aligns with CWE-665 improper initialization and CWE-367 time-of-check time-of-use issues, demonstrating how inadequate input validation can create exploitable conditions in interactive systems.
The operational impact of this vulnerability extends beyond simple user experience degradation to potential security compromise scenarios. Attackers could exploit this weakness to bypass security prompts by rapidly triggering dialog behaviors, potentially causing users to inadvertently dismiss important warnings about certificate mismatches, phishing attempts, or permission requests. The timing aspect makes this particularly dangerous in phishing attacks where attackers might craft specific interaction patterns to exploit the race condition and bypass security measures. Users may unknowingly confirm malicious actions or dismiss security warnings, creating a pathway for credential theft, data exfiltration, or other malicious activities. This vulnerability particularly impacts enterprise environments where security prompts are critical for protecting against various attack vectors and where user interaction patterns may be more predictable or exploitable.
Mitigation strategies for this vulnerability focus primarily on software updates and input validation improvements. Organizations should immediately deploy patches for Firefox 119, Firefox ESR 115.4, and Thunderbird 115.4.1 to address the underlying implementation flaw. System administrators should prioritize updating these browser versions across all affected platforms, particularly in enterprise environments where the risk of exploitation is higher. Additionally, security teams should monitor for potential exploitation attempts that might leverage this vulnerability to bypass security controls, as indicated by ATT&CK technique T1059.007 for user execution and T1566 for phishing attacks. Implementing additional input validation at the application level and ensuring proper delay mechanisms in user interface components can provide additional protection against similar timing-based vulnerabilities. Regular security assessments should include testing for race conditions in interactive elements to identify potential similar flaws in other applications.