CVE-2011-2372 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.6.23 and 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 do not prevent the starting of a download in response to the holding of the Enter key, which allows user-assisted remote attackers to bypass intended access restrictions via a crafted web site.
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Analysis
by VulDB Data Team • 11/20/2021
This vulnerability exists in Mozilla Firefox versions prior to 3.6.23 and 4.x through 6, as well as in Thunderbird versions before 7.0 and SeaMonkey versions before 2.4. The flaw stems from insufficient input validation and event handling mechanisms that fail to properly restrict download initiation through keyboard interactions. Specifically, the software does not adequately prevent automatic download execution when users hold the enter key while interacting with web content, creating an unintended execution path that can be exploited by malicious actors.
The technical implementation of this vulnerability involves the improper handling of keyboard events, particularly the enter key press, within the download initiation framework. When a user holds the enter key while browsing a malicious website, the system processes multiple download requests that would normally require explicit user interaction. This behavior represents a failure in access control enforcement and input sanitization, allowing attackers to bypass intended security restrictions that typically require explicit user confirmation before initiating downloads. The vulnerability manifests as a lack of proper event filtering and state management within the browser's download subsystem.
From an operational perspective, this vulnerability creates significant security implications for users who may inadvertently trigger malicious downloads without explicit confirmation. Attackers can craft web pages that automatically initiate downloads when users interact with specific elements while holding the enter key, potentially leading to the execution of malicious software, unauthorized data transfers, or other harmful actions. The user-assisted nature of the attack means that successful exploitation requires some form of user interaction, but the automated nature of the download initiation makes it particularly dangerous. This vulnerability aligns with CWE-352, which addresses Cross-Site Request Forgery (CSRF) and improper access control issues, and can be categorized under ATT&CK technique T1195.001 for 'Supply Chain Compromise' when used in malicious website contexts.
The impact of this vulnerability extends beyond simple download initiation, as it can be leveraged to bypass various security controls that rely on explicit user confirmation. Users who encounter malicious websites may unknowingly trigger multiple downloads, potentially including malware payloads, without realizing they have been compromised. The vulnerability's persistence across multiple browser versions and applications indicates a systemic issue in how these products handle keyboard event propagation and download initiation. Organizations should consider this vulnerability as part of a broader threat landscape that includes various forms of automated exploitation and social engineering attacks. The recommended mitigation involves updating to the patched versions of these applications, which implement proper event handling and access control measures to prevent automatic download initiation through keyboard interactions. Additionally, users should be educated about the risks of holding keys during web browsing and the importance of verifying download sources before accepting any automatic download requests.