CVE-2006-2057 in Firefox
Summary
by MITRE
Argument injection vulnerability in Mozilla Firefox 1.0.6 allows user-assisted remote attackers to modify command line arguments to an invoked mail client via " (double quote) characters in a mailto: scheme handler, as demonstrated by launching Microsoft Outlook with an arbitrary filename as an attachment. NOTE: it is not clear whether this issue is implementation-specific or a problem in the Microsoft API.
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Analysis
by VulDB Data Team • 07/25/2018
The CVE-2006-2057 vulnerability represents a critical argument injection flaw in Mozilla Firefox version 1.0.6 that demonstrates the dangerous intersection of web browser security and operating system command execution. This vulnerability specifically targets the mailto: scheme handler implementation within Firefox, which is responsible for launching external mail client applications when users click on email links. The flaw occurs when Firefox processes mailto URLs containing double quote characters that are not properly sanitized or escaped before being passed to the underlying operating system's mail client launcher. The vulnerability operates through user-assisted remote exploitation where an attacker crafts a malicious mailto URL that, when clicked by a victim, can manipulate the command line arguments passed to the invoked mail client.
The technical nature of this vulnerability aligns with CWE-74, which describes improper neutralization of special elements used in a command, and CWE-94, which addresses improper control of generation of code. When Firefox encounters a mailto URL with double quote characters, it fails to properly escape these special characters before passing them to the system call that launches the mail client. This creates an injection point where arbitrary command line arguments can be injected into the mail client invocation process. The demonstration case shows how Microsoft Outlook can be launched with an arbitrary filename as an attachment, which represents a significant security risk as it could potentially allow attackers to execute arbitrary files or commands through the mail client's command processing capabilities. The vulnerability is particularly concerning because it leverages the trust relationship between web browsers and operating system applications, where the browser acts as an intermediary that should properly sanitize inputs before passing them to system-level functions.
The operational impact of this vulnerability extends beyond simple command injection, as it can potentially enable more sophisticated attacks depending on the capabilities of the targeted mail client and operating system. Attackers could exploit this vulnerability to execute arbitrary code through the mail client's argument parsing, potentially leading to privilege escalation or system compromise. The vulnerability's effectiveness depends on the specific mail client implementation and how it handles command line arguments, making it potentially implementation-specific as noted in the original description. The issue demonstrates how web browsers, which are designed to be safe sandboxes for user interactions, can inadvertently create attack vectors that bypass security boundaries when they fail to properly sanitize inputs before delegating to system-level applications. This vulnerability represents a classic example of how web security flaws can cascade into operating system-level risks, particularly when browsers act as gateways to native application execution.
Mitigation strategies for CVE-2006-2057 should focus on proper input sanitization and escaping within the browser's mailto handler implementation. The most effective approach involves ensuring that all special characters, particularly double quotes, are properly escaped or quoted before being passed to system calls. This aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, where web-based command injection vulnerabilities are addressed through proper input validation and sanitization. Security patches for this vulnerability would typically involve implementing proper escaping mechanisms in the mailto URL processing code, ensuring that any special characters are neutralized before system command execution. Additionally, browser vendors should consider implementing stricter sandboxing of external application launches and potentially implementing more robust input validation for all URL scheme handlers. The vulnerability underscores the importance of proper input handling in web applications and demonstrates why security-conscious development practices, including input sanitization and proper command construction, are essential when interfacing with operating system functions. Organizations should also consider implementing network-level protections and user education to reduce the risk of exploitation, though the primary fix must come from proper browser implementation.