CVE-2002-2312 in Web Browser
Summary
by MITRE
Opera 6.0.1 allows remote attackers to upload arbitrary file contents when users press a key corresponding to the JavaScript (1) event.ctrlKey or (2) event.shiftKey onkeydown event contained in a webpage.
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Analysis
by VulDB Data Team • 07/04/2025
This vulnerability exists in Opera 6.0.1 web browser where the application fails to properly validate file upload operations when specific keyboard events are triggered. The flaw occurs during the processing of onkeydown JavaScript events that involve the ctrlKey or shiftKey properties, allowing remote attackers to manipulate the browser's file handling mechanisms. The vulnerability stems from inadequate input sanitization and improper handling of keyboard event combinations that should not influence file upload operations. Attackers can exploit this by crafting malicious web pages that contain JavaScript code designed to trigger these specific keyboard events, thereby bypassing normal file upload restrictions. The security issue manifests when users interact with compromised web content and press keys that correspond to the ctrlKey or shiftKey properties within onkeydown event handlers, potentially enabling unauthorized file operations. This represents a classic case of improper input validation where the browser fails to distinguish between legitimate user interactions and malicious attempts to manipulate file system operations through keyboard events.
The technical implementation of this vulnerability involves the browser's JavaScript engine processing keyboard events without adequate security checks for file operations. When a user presses keys that activate the ctrlKey or shiftKey properties during a webpage's onkeydown event, the browser's file upload handler receives unexpected input parameters that it cannot properly validate. This creates an opportunity for attackers to inject arbitrary file contents into the browser's upload mechanism, potentially leading to unauthorized file creation or modification on the user's system. The vulnerability specifically affects the browser's interpretation of keyboard events within JavaScript contexts, where the normal flow of event handling becomes compromised. The flaw essentially allows attackers to manipulate the browser's interpretation of user intent during file upload operations, bypassing built-in security restrictions that should prevent such unauthorized actions.
The operational impact of this vulnerability extends beyond simple file upload manipulation, potentially enabling more serious security breaches including arbitrary code execution, privilege escalation, and system compromise. Users who visit malicious websites and inadvertently trigger the affected keyboard events may unknowingly allow attackers to upload malicious files to their systems, creating persistent security threats. The vulnerability affects the browser's core security model by allowing attackers to bypass normal file system access controls and potentially gain unauthorized access to sensitive data. Remote attackers can leverage this weakness to establish persistent backdoors or execute malicious payloads through the compromised file upload mechanisms. The risk is particularly elevated in environments where users frequently visit untrusted websites or where browser security settings are not properly configured to mitigate such attacks.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and event handling within the browser's JavaScript engine. Security patches should address the specific keyboard event processing logic to ensure that ctrlKey and shiftKey combinations cannot be used to manipulate file upload operations. Browser vendors should implement strict validation of file operations triggered by keyboard events and establish clear boundaries between legitimate user interactions and potentially malicious attempts to manipulate file system operations. Users should be advised to keep their browsers updated with the latest security patches and to avoid visiting untrusted websites. Organizations should implement network-level protections such as web application firewalls and content filtering systems to detect and block malicious web content that attempts to exploit this vulnerability. The fix should align with security best practices outlined in the CWE database, specifically addressing weaknesses related to improper input validation and event handling in web browsers. This vulnerability also relates to ATT&CK techniques involving privilege escalation and persistence through file manipulation, making comprehensive mitigation essential for protecting user systems from exploitation.