CVE-2005-0146 in Firefox
Summary
by MITRE
Firefox before 1.0 and Mozilla before 1.7.5 allow remote attackers to obtain sensitive data from the clipboard via Javascript that generates a middle-click event on systems for which a middle-click performs a paste operation.
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Analysis
by VulDB Data Team • 06/06/2019
This vulnerability exists in mozilla firefox versions prior to 1.0 and mozilla browser versions prior to 1.7.5 where javascript code can exploit a security flaw to access clipboard contents through simulated middle-click events. The technical implementation relies on the ability of javascript to generate mouse events that mimic user interactions with the system's clipboard functionality. When a user's system is configured to paste clipboard contents with a middle-click operation, malicious javascript can simulate this action to potentially retrieve sensitive information that was copied to the clipboard by the user. This represents a classic cross-site scripting attack vector where the attacker leverages the browser's event handling mechanisms to bypass normal security boundaries. The vulnerability is categorized under cwe-200 which deals with information exposure and specifically addresses the improper restriction of information exposure via clipboard access. From an attack perspective this flaw aligns with techniques described in the attack pattern taxonomy where adversaries exploit browser capabilities to access user data without proper authorization. The operational impact is significant as it allows attackers to harvest sensitive data including passwords, personal information, and other clipboard contents that users have copied for legitimate purposes. This vulnerability demonstrates the inherent risks when browser javascript engines can manipulate system-level events and user interface interactions that are normally protected from programmatic access. The flaw essentially creates a backdoor through which malicious code can access data that should remain private to the user's session. Security researchers have identified this as a critical issue because it leverages legitimate browser functionality to achieve unauthorized data access, making it particularly difficult to detect and prevent through traditional security measures.
The vulnerability operates through a specific exploitation mechanism where javascript code can programmatically generate middle-click mouse events that trigger the system's paste functionality. When the browser processes these events, it can inadvertently expose clipboard contents to the executing javascript context. This occurs because the browser's event handling system does not properly validate or restrict the access permissions for clipboard operations when triggered through automated events. The attack requires a specific system configuration where middle-click paste is enabled, but this is common across many desktop environments. The exploitation process involves creating a malicious webpage that contains javascript code designed to simulate the middle-click event, which then triggers the system paste operation and potentially exposes clipboard contents to the attacker. This vulnerability type falls under the broader category of insecure direct object reference issues and demonstrates how browser-based attacks can leverage operating system integration points to achieve unauthorized access. The security implications extend beyond simple information disclosure as clipboard contents often contain highly sensitive data including authentication credentials, personal identification information, and proprietary business data. The attack vector is particularly concerning because it can be executed silently in the background without user awareness, making it difficult to detect through conventional user monitoring approaches.
Mitigation strategies for this vulnerability involve implementing proper access controls and event validation within the browser's javascript execution environment. The most effective approach is to update to patched versions of firefox and mozilla browsers where the security flaw has been addressed through enhanced event handling and clipboard access restrictions. Browser vendors should implement stricter controls over which javascript operations can trigger system-level events, particularly those that access user data or system resources. The fix typically involves modifying the browser's event processing pipeline to prevent automatic clipboard access through simulated mouse events while maintaining legitimate user functionality. Organizations should also implement browser security policies that limit javascript capabilities and monitor for suspicious event handling patterns. From a compliance perspective this vulnerability relates to standards such as iso/iec 27001 and nist cybersecurity framework where organizations must protect against unauthorized access to sensitive information. The mitigation approach should include regular security updates, browser hardening procedures, and user education about the risks of visiting untrusted websites. Network security controls such as web application firewalls and content filtering systems can also help detect and block malicious javascript that attempts to exploit this vulnerability. Additionally, system administrators should review and modify default middle-click paste configurations where possible to reduce the attack surface. The vulnerability highlights the importance of maintaining current security patches and implementing defense-in-depth strategies that protect against both known and emerging threats. Security teams should also conduct regular vulnerability assessments to identify similar issues that may exist in other browser components or integrated system functionality.