CVE-2012-0458 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.6.28 and 4.x through 10.0, Firefox ESR 10.x before 10.0.3, Thunderbird before 3.1.20 and 5.0 through 10.0, Thunderbird ESR 10.x before 10.0.3, and SeaMonkey before 2.8 do not properly restrict setting the home page through the dragging of a URL to the home button, which allows user-assisted remote attackers to execute arbitrary JavaScript code with chrome privileges via a javascript: URL that is later interpreted in the about:sessionrestore context.
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Analysis
by VulDB Data Team • 10/21/2024
This vulnerability exists in multiple Mozilla applications including Firefox, Thunderbird, and SeaMonkey, where the software fails to properly validate URL inputs when setting a home page through drag and drop operations. The flaw specifically occurs when a user drags a javascript: URL to the home button, allowing malicious actors to craft specially formatted URLs that execute arbitrary code with chrome privileges. The vulnerability affects versions prior to Firefox 3.6.28, 4.x through 10.0, Firefox ESR 10.x before 10.0.3, Thunderbird before 3.1.20, 5.0 through 10.0, Thunderbird ESR 10.x before 10.0.3, and SeaMonkey before 2.8. The security risk stems from the improper restriction of URL handling during the home page setting process, which creates an attack vector that bypasses normal security boundaries.
The technical implementation of this vulnerability involves the manipulation of the browser's home button functionality through drag and drop operations. When a user drags a javascript: URL to the home button, the application stores this URL without adequate sanitization or validation. Later, when the about:sessionrestore context is loaded, the stored javascript: URL is interpreted and executed with chrome privileges, which are elevated permissions that allow access to sensitive browser functions and potentially user data. This represents a classic cross-site scripting vulnerability that has been escalated to a privilege escalation issue due to the chrome privileges being granted to the malicious code.
The operational impact of this vulnerability is significant as it allows remote attackers to execute arbitrary JavaScript code with elevated privileges, potentially leading to complete browser compromise. Attackers can craft malicious javascript: URLs that, when dragged to the home button, will execute code with access to browser internals, cookies, local storage, and potentially sensitive user information. The user-assisted nature of the attack means that the victim must perform a specific action by dragging a malicious URL to the home button, but this interaction is often performed without security awareness. The vulnerability can be exploited to perform actions such as stealing session cookies, modifying browser settings, or even installing malware that persists across browser sessions.
This vulnerability aligns with CWE-79 Cross-Site Scripting and CWE-20 Improper Input Validation, representing a failure to properly validate and sanitize user inputs during critical browser operations. From an ATT&CK perspective, this maps to T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, as the attack chain involves executing malicious scripts with elevated privileges. The vulnerability demonstrates a critical flaw in the browser's input validation mechanisms during drag and drop operations, particularly when dealing with protocol handlers that should be restricted. Organizations should implement immediate patch management to update all affected versions, while also considering browser security policies that restrict the execution of javascript: URLs in privileged contexts. The remediation involves ensuring proper URL validation and sanitization during home page setting operations, particularly when handling drag and drop events that could introduce malicious content into the browser's trusted execution environment.