CVE-2006-2058 in Avant Browser
Summary
by MITRE
Argument injection vulnerability in Avant Browser 10.1 Build 17 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 • 09/06/2017
The CVE-2006-2058 vulnerability represents a critical argument injection flaw in Avant Browser version 10.1 Build 17 that enables remote attackers to manipulate command line arguments passed to external mail clients through maliciously crafted mailto: URLs. This vulnerability operates through a specific manipulation of the mailto scheme handler where double quote characters can be inserted into the URL to inject additional arguments into the invoked mail client process. The technical implementation exploits the browser's handling of mailto URLs without proper sanitization or escaping of special characters that have meaning in command line contexts.
The vulnerability specifically targets the interaction between the web browser and external mail client applications, particularly Microsoft Outlook, by leveraging the mailto: URI scheme to invoke the mail client with crafted arguments. When a user clicks on a malicious mailto: URL containing double quote characters, the browser passes these arguments directly to the mail client executable without proper argument separation or escaping. This creates a command injection scenario where additional parameters can be injected into the command line, potentially allowing attackers to specify arbitrary filenames as attachments or execute other malicious operations within the context of the mail client process.
From an operational perspective, this vulnerability demonstrates a classic case of insufficient input validation and sanitization in web browser implementations of URI handlers. The attack requires user interaction through clicking a malicious link, making it a user-assisted remote attack vector that could be delivered through various means including phishing emails, malicious websites, or compromised web applications. The impact extends beyond simple argument injection to potentially allow execution of arbitrary commands within the context of the mail client, depending on the target application's behavior and the specific arguments injected. This vulnerability aligns with CWE-77 and CWE-78 categories related to command injection flaws in software that processes external inputs without proper sanitization.
The security implications of CVE-2006-2058 are significant as it demonstrates how seemingly benign URI scheme handling can become a vector for privilege escalation and arbitrary code execution. The vulnerability exposes a fundamental flaw in how browsers handle external application invocation through URI schemes, creating a potential attack surface that could be exploited to bypass security controls. Attackers could leverage this flaw to execute malicious code with the privileges of the user running the mail client, potentially leading to full system compromise. The issue's unclear implementation specificity regarding whether it affects Microsoft API directly or is browser-specific highlights the complexity of such vulnerabilities and the need for comprehensive security testing across different components in the software stack.
Mitigation strategies for this vulnerability should focus on implementing proper input sanitization and escaping of special characters in URI handlers, particularly those involving external application invocation. Browser vendors should ensure that all arguments passed to external applications through URI schemes are properly escaped or quoted to prevent command injection. Additionally, security patches should include validation of URI components to prevent injection of potentially dangerous characters. The vulnerability underscores the importance of following secure coding practices and adhering to security standards such as those outlined in the OWASP Top Ten and NIST guidelines for preventing command injection attacks. Organizations should also implement user education programs to recognize and avoid clicking suspicious links that may contain malicious mailto: URLs designed to exploit such vulnerabilities.