CVE-2004-2659 in Web Browser
Summary
by MITRE
Opera offers an Open button to verify that a user wishes to execute a downloaded file, which allows user-assisted remote attackers to construct a race condition that tricks a user into clicking Open via a request for a different mouse or keyboard action very shortly before the Open dialog appears. NOTE: this is a different issue than CVE-2005-2407.
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Analysis
by VulDB Data Team • 04/22/2019
This vulnerability resides in the Opera web browser's file execution handling mechanism, specifically within the Open dialog functionality designed to verify user intent before executing downloaded files. The flaw represents a sophisticated race condition attack vector that exploits the timing gap between when a malicious web page triggers a download request and when the user interface prompts for confirmation. Attackers can manipulate the sequence of user interaction events to create a scenario where the Open dialog appears almost immediately after a seemingly unrelated mouse or keyboard action, effectively tricking users into inadvertently confirming file execution. This vulnerability demonstrates a critical weakness in the browser's user interface event handling and timing mechanisms that should have prevented such manipulation.
The technical implementation of this vulnerability involves a precise timing attack against Opera's download confirmation dialog. When a user downloads a file, the browser presents an Open dialog that should require explicit user interaction to proceed with execution. However, the race condition occurs because the browser's event processing system does not adequately synchronize the timing of different user input events. Malicious actors can construct web pages that issue multiple rapid-fire input events, creating a window where the Open dialog appears while the system is still processing earlier input actions. This allows attackers to effectively automate the user's confirmation action by ensuring that the Open button receives focus and is clicked automatically within milliseconds of appearing. The vulnerability is classified under CWE-362, which addresses race conditions in security-critical operations, specifically those involving concurrent access to shared resources or user interface elements.
The operational impact of this vulnerability extends beyond simple file execution manipulation to represent a significant escalation of privileges through social engineering. Users who download files from untrusted sources become vulnerable to automatic execution of potentially malicious content, bypassing the intended security controls designed to prevent such automated actions. This attack vector is particularly dangerous because it leverages the user's own interaction patterns against them, making it difficult to detect and prevent through traditional security measures. The vulnerability effectively removes the user's control over file execution decisions, transforming a security feature designed to protect users into an attack surface. Security professionals should note that this represents a form of user interface manipulation that aligns with techniques described in ATT&CK framework under the T1203 category for exploitation of software vulnerabilities, specifically targeting the user's interaction with security prompts.
Mitigation strategies for this vulnerability require both immediate browser updates and user education initiatives. Browser vendors should implement proper input event synchronization mechanisms that prevent rapid succession of different input types from affecting the same security dialog. The fix should include introducing minimum time intervals between different user interaction events that could potentially influence security prompts, as well as implementing more robust state management for security dialogs. Users should be educated about the importance of carefully reviewing all download confirmations and avoiding automated interactions with browser security prompts. Additionally, system administrators should consider implementing browser hardening policies that disable or restrict automatic download execution features, particularly in environments where security is paramount. The vulnerability also highlights the importance of comprehensive testing for race conditions in security-critical user interface components, as such issues often remain undetected until exploited in real-world scenarios. Organizations should conduct regular security assessments focusing on user interaction timing and event handling within security-critical applications.