CVE-2004-1491 in Web Browser
Summary
by MITRE
Opera 7.54 and earlier uses kfmclient exec to handle unknown MIME types, which allows remote attackers to execute arbitrary code via a shortcut or launcher that contains an Exec entry.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 11/29/2024
The vulnerability described in CVE-2004-1491 represents a critical security flaw in Opera web browser versions 7.54 and earlier, specifically within their handling of unknown MIME types through the kfmclient exec functionality. This issue arises from the browser's improper execution of external commands when processing certain file types that it cannot natively handle, creating a potential code execution vector for remote attackers. The vulnerability is particularly concerning as it leverages the KDE file management system's kfmclient utility to execute arbitrary commands, bypassing normal browser security boundaries and potentially allowing attackers to gain unauthorized access to affected systems.
The technical flaw stems from Opera's decision to delegate the handling of unknown MIME types to kfmclient exec, which is designed for KDE desktop environment integration. When Opera encounters a file type it does not recognize, it attempts to execute the file through kfmclient, which can interpret and execute commands specified in Exec entries within shortcut or launcher files. This design flaw allows attackers to craft malicious files containing specially formatted Exec entries that, when processed by Opera, execute arbitrary code on the victim's system. The vulnerability is classified under CWE-78 as a failure to sanitize command line arguments, specifically involving the execution of system commands without proper input validation or sanitization.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to perform a wide range of malicious activities including but not limited to privilege escalation, data theft, system compromise, and persistence mechanisms. Remote attackers can exploit this vulnerability by crafting malicious web content or file downloads that trigger the vulnerable code path, potentially leading to complete system compromise. The attack surface is broad as it can be triggered through various vectors including web browsing, email attachments, or malicious downloads that contain the specially crafted shortcut files designed to exploit this weakness. This vulnerability directly maps to several ATT&CK techniques including command and control through execution of malicious code, privilege escalation, and initial access through malicious file downloads.
Mitigation strategies for this vulnerability should focus on immediate browser updates to versions that address the kfmclient execution flaw, along with implementing network-level controls such as content filtering and web application firewalls to prevent access to potentially malicious content. System administrators should also consider restricting the execution of kfmclient in sensitive environments and implementing strict file type validation for downloaded content. The most effective long-term solution involves updating to modern browser versions that do not rely on external command execution for MIME type handling, while also implementing comprehensive security awareness training to prevent users from inadvertently downloading and executing malicious files. Organizations should also consider implementing sandboxing mechanisms and privilege separation to limit the potential damage from successful exploitation attempts, ensuring that even if an attacker succeeds in executing arbitrary code, the impact remains contained within a restricted environment.