CVE-2004-0489 in Mac OS X
Summary
by MITRE
Argument injection vulnerability in the SSH URI handler for Safari on Mac OS 10.3.3 and earlier allows remote attackers to (1) execute arbitrary code via the ProxyCommand option or (2) conduct port forwarding via the -R option.
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Analysis
by VulDB Data Team • 07/07/2017
The vulnerability described in CVE-2004-0489 represents a critical argument injection flaw within Safari's SSH URI handler implementation on Mac OS 10.3.3 and earlier versions. This security weakness specifically targets how the web browser processes SSH connection requests through URI schemes, creating a pathway for malicious actors to manipulate command execution parameters. The vulnerability stems from inadequate input validation and sanitization within the Safari browser's handling of SSH protocol connections, particularly when processing the ProxyCommand and -R options that are fundamental to SSH functionality.
The technical exploitation of this vulnerability occurs through the manipulation of SSH URI parameters that Safari passes to the underlying SSH client. When a user clicks on an SSH link in a web page, Safari's URI handler constructs command-line arguments for the SSH client by directly incorporating user-supplied data without proper sanitization. The ProxyCommand option allows attackers to specify arbitrary commands that execute on the target system, while the -R option enables port forwarding attacks that can redirect network traffic. This creates two distinct attack vectors that can be leveraged for remote code execution and network reconnaissance. The flaw aligns with CWE-94, which describes the injection of code or commands into a system, and specifically relates to CWE-77, which covers command injection vulnerabilities.
The operational impact of this vulnerability is severe and multifaceted, as it enables attackers to execute arbitrary commands on systems running vulnerable versions of Safari and Mac OS. Remote attackers can leverage this weakness to gain unauthorized access to systems, establish persistent backdoors, or conduct further network reconnaissance. The port forwarding capabilities through the -R option allow attackers to create covert channels or redirect traffic through compromised systems, effectively enabling man-in-the-middle attacks. This vulnerability particularly affects enterprise environments where users may browse untrusted websites and click on malicious SSH links, potentially compromising entire networks. The attack surface extends beyond individual user systems to include corporate networks where Safari is the default browser for accessing SSH resources.
Mitigation strategies for CVE-2004-0489 require immediate system updates and configuration changes to prevent exploitation. The most effective approach involves upgrading to Mac OS 10.3.4 or later versions where Apple addressed this vulnerability through improved input validation in Safari's SSH URI handling. Organizations should also implement network-level restrictions on SSH traffic and disable unnecessary SSH functionality in web browsers when not required for business operations. Security professionals should consider implementing web application firewalls to monitor and filter SSH URI requests, as well as establishing user education programs to raise awareness about the dangers of clicking on untrusted SSH links. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for command and scripting interpreter and T1021.004 for remote service protocol. The recommended security controls include input validation, privilege separation, and regular system patching to address similar vulnerabilities in the SSH protocol implementation. Organizations should also conduct regular vulnerability assessments to identify and remediate similar injection flaws in other applications that handle command-line arguments or execute system commands based on user input.