CVE-2007-4039 in Mozilla
Summary
by MITRE
Argument injection vulnerability involving Mozilla, when certain URIs are registered, allows remote attackers to conduct cross-browser scripting attacks and execute arbitrary commands via shell metacharacters in an unspecified URI, which are inserted into the command line when invoking the handling process, a similar issue to CVE-2007-3670.
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Analysis
by VulDB Data Team • 04/03/2025
The vulnerability described in CVE-2007-4039 represents a critical argument injection flaw within the Mozilla browser ecosystem that enables remote attackers to execute arbitrary commands through carefully crafted URI schemes. This vulnerability operates at the intersection of web browser security and operating system command execution, creating a dangerous attack surface where malicious web content can leverage browser URI handling mechanisms to compromise system integrity. The flaw specifically manifests when certain URIs are registered within the browser environment, allowing attackers to inject shell metacharacters into command line arguments that are subsequently processed by the underlying operating system. This creates a direct pathway for cross-browser scripting attacks that can bypass traditional web security boundaries and extend into the host operating system.
The technical implementation of this vulnerability relies on the improper sanitization of URI arguments during the process invocation phase. When Mozilla processes specific URI schemes that are registered on the system, it fails to adequately validate or escape special shell metacharacters contained within the URI parameters. This oversight allows attackers to craft malicious URIs that, when processed, insert dangerous command sequences into system command lines. The vulnerability shares similarities with CVE-2007-3670, indicating a broader pattern of URI handling flaws within the browser's interaction with operating system processes. This type of vulnerability is classified as a command injection attack vector, where the attacker's input is interpreted as executable commands rather than data, fundamentally compromising the security boundary between the browser and the underlying system. The flaw operates under CWE-77 which specifically addresses command injection vulnerabilities, and aligns with ATT&CK technique T1059.007 for command and script injection.
The operational impact of this vulnerability extends beyond simple cross-browser scripting to encompass full system compromise capabilities. Attackers can leverage this flaw to execute arbitrary code with the privileges of the user running the browser, potentially leading to complete system takeover. The attack surface is particularly concerning because it can be triggered through seemingly benign web navigation or embedded content, making it difficult to detect and prevent through traditional security measures. The vulnerability's persistence across different browser versions and operating systems indicates a fundamental design flaw in how Mozilla handles URI registration and command line argument processing. This creates a significant risk for enterprise environments where users may inadvertently encounter malicious content, and for users who browse untrusted websites with browsers that have registered custom URI handlers.
Mitigation strategies for CVE-2007-4039 must address both the immediate security gap and prevent similar vulnerabilities from emerging in the future. Organizations should implement strict URI validation policies and avoid registering custom URI handlers unless absolutely necessary for legitimate business functions. Browser configuration should disable or restrict automatic execution of external handlers, and system administrators should regularly audit registered URI schemes to identify potential attack vectors. The implementation of proper input sanitization and escaping mechanisms within the browser's URI processing pipeline is essential to prevent shell metacharacter injection. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping browser software updated. Security solutions should include network monitoring to detect suspicious URI patterns and command execution attempts, while system hardening measures should restrict the privileges of browser processes to minimize potential damage from successful exploitation attempts. The vulnerability highlights the importance of defense-in-depth strategies that protect against both web-based and system-level attack vectors, particularly when dealing with applications that interact with operating system processes through command line interfaces.