CVE-2009-3370 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.0.15, and 3.5.x before 3.5.4, allows remote attackers to read form history by forging mouse and keyboard events that leverage the auto-fill feature to populate form fields, in an attacker-readable form, with history entries.
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Analysis
by VulDB Data Team • 08/24/2021
This vulnerability exists in mozilla firefox versions prior to 3.0.15 and 3.5.x versions before 3.5.4, representing a significant security flaw that allows remote attackers to access sensitive form history data through crafted mouse and keyboard event manipulation. The vulnerability specifically exploits the browser's auto-fill feature which is designed to populate form fields with previously entered values for user convenience. Attackers can forge mouse and keyboard events that trigger this auto-fill functionality in a manner that makes the history entries readable by the attacker, effectively bypassing normal security boundaries that should prevent such information disclosure.
The technical implementation of this vulnerability leverages the browser's event handling system and auto-fill mechanisms to manipulate form fields in ways that were not properly secured against malicious input. When firefox processes forged events, the auto-fill feature responds by populating form fields with history entries from the user's browsing history, including previously entered usernames, passwords, and other sensitive form data. This occurs because the browser's security model did not adequately validate the source and legitimacy of events that trigger auto-fill functionality, allowing remote attackers to simulate user interactions that would normally be restricted to legitimate user input.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks including credential theft and targeted phishing operations. Attackers can craft malicious web pages that automatically populate form fields with history entries from the victim's browser, making it appear as though the victim has already entered their credentials or personal information. This creates a false sense of legitimacy that could be exploited in social engineering attacks or to harvest sensitive data from users who might not realize they are being manipulated. The vulnerability particularly affects users who have extensive browsing histories and frequently use auto-fill features for online forms, making it a significant concern for privacy and security.
This vulnerability maps directly to CWE-200, which describes the improper exposure of sensitive information, and aligns with ATT&CK technique T1531 for "Account Access Removal" and T1566 for "Phishing" as it enables attackers to harvest credentials through deceptive form manipulation. The flaw represents a failure in input validation and event source verification, as the browser should have implemented proper security checks to ensure that auto-fill operations are only triggered by legitimate user interactions. Mitigation strategies include updating to affected firefox versions where the vulnerability has been patched, implementing browser security policies that restrict auto-fill behavior, and educating users about the risks of visiting untrusted websites that may attempt to exploit such vulnerabilities. Organizations should also consider implementing additional security measures such as browser isolation techniques and monitoring for suspicious auto-fill activity that could indicate exploitation attempts.