CVE-2011-2984 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.6.20, SeaMonkey 2.x, Thunderbird 3.x before 3.1.12, and possibly other products does not properly handle the dropping of a tab element, which allows remote attackers to execute arbitrary JavaScript code with chrome privileges by establishing a content area and registering for drop events.
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Analysis
by VulDB Data Team • 11/18/2021
This vulnerability exists in multiple Mozilla applications including Firefox versions prior to 3.6.20, SeaMonkey 2.x, and Thunderbird 3.x versions before 3.1.12. The flaw stems from improper handling of tab element dropping operations within the browser's content rendering system. When a malicious web page attempts to drop a tab element, the application fails to properly validate or sanitize the operation, creating a potential privilege escalation vector. The vulnerability specifically affects the browser's drag and drop functionality, which is commonly used for user interface interactions and content manipulation.
The technical implementation of this vulnerability involves the browser's content area handling mechanism where drop events are registered and processed. When a tab element is dropped, the system should validate that the operation originates from a trusted source and properly restricts the execution context of any associated JavaScript code. However, the flaw allows malicious code to establish a content area that can register for drop events, thereby gaining access to chrome privileges which normally should be restricted to the browser's privileged code. This represents a classic cross-site scripting vulnerability that has been escalated to a privilege escalation attack.
The operational impact of this vulnerability is significant as it allows remote attackers to execute arbitrary JavaScript code with elevated privileges. The chrome privileges provide access to sensitive browser functions, including the ability to read and modify user data, access local files, and potentially escalate the attack further. Attackers can craft malicious web pages that exploit this vulnerability by creating a tab element drop event that triggers the execution of malicious JavaScript code in the privileged context. This vulnerability can be exploited through various attack vectors including malicious websites, email attachments, or compromised web applications.
The vulnerability aligns with CWE-94, which describes the improper control of generation of code, specifically in the context of allowing untrusted input to be interpreted as code. It also relates to ATT&CK technique T1059.007 for execution through JavaScript and T1068 for privilege escalation. The flaw demonstrates a lack of proper input validation and privilege separation in the browser's drag and drop implementation, allowing untrusted content to execute code with elevated permissions. This represents a critical security issue that could enable attackers to bypass security boundaries and gain unauthorized access to user data or system resources.
Mitigation strategies include immediate updating of affected applications to versions that contain patches for this vulnerability. Organizations should implement web filtering solutions to block access to known malicious domains and monitor for suspicious tab element drop operations. Browser security configurations should be hardened by disabling unnecessary drag and drop functionality where possible. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping browser software updated. Security monitoring should include detection of anomalous JavaScript execution patterns and privilege escalation attempts. The patch for this vulnerability specifically addresses the improper handling of drop events and implements proper validation of tab element operations to prevent unauthorized privilege escalation.