CVE-2004-0411 in Konqueror
Summary
by MITRE
The URI handlers in Konqueror for KDE 3.2.2 and earlier do not properly filter "-" characters that begin a hostname in a (1) telnet, (2) rlogin, (3) ssh, or (4) mailto URI, which allows remote attackers to manipulate the options that are passed to the associated programs, possibly to read arbitrary files or execute arbitrary code.
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Analysis
by VulDB Data Team • 03/09/2021
The vulnerability described in CVE-2004-0411 represents a critical input validation flaw in the Konqueror web browser's URI handling mechanism within KDE 3.2.2 and earlier versions. This issue specifically affects four distinct URI schemes including telnet, rlogin, ssh, and mailto protocols that are commonly used for remote access and email functionality. The flaw stems from insufficient sanitization of hostname parameters within these URI handlers, creating a pathway for malicious actors to manipulate command-line arguments passed to underlying system utilities. The vulnerability is particularly concerning because it operates at the application level where user interactions with web content can directly translate into system-level command execution. Attackers can exploit this weakness by crafting specially formatted URIs that leverage the improper handling of hyphen characters at the beginning of hostnames, which are typically valid in DNS naming conventions but become problematic when processed as command-line arguments.
The technical exploitation of this vulnerability occurs through the manipulation of URI parsing logic where the Konqueror browser fails to properly sanitize input before passing it to external programs. When a user clicks on a malicious URI containing a hostname that begins with a hyphen character, the browser does not adequately filter or escape these characters before executing the associated command-line utilities. This oversight allows attackers to inject additional command-line options or arguments that would normally be restricted, potentially enabling unauthorized access to system resources. The vulnerability specifically targets the way Konqueror processes these URI schemes by directly passing parsed hostname components to programs like telnet, rlogin, ssh, and mailto handlers without proper validation. The lack of input filtering creates a command injection scenario where attackers can append arbitrary command-line parameters to legitimate programs, effectively bypassing normal security boundaries that would otherwise prevent such operations.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data exfiltration capabilities. Remote attackers who can influence user interactions with web content can exploit this flaw to execute arbitrary code on vulnerable systems, potentially gaining complete control over affected machines. The attack vector is particularly dangerous because it requires no local privileges and can be delivered through web-based attacks, making it accessible to a wide range of threat actors. Depending on the target system configuration, successful exploitation could allow attackers to read arbitrary files from the system, execute malicious commands, or even establish persistent backdoors. The vulnerability affects all users of Konqueror browsers running KDE 3.2.2 or earlier versions, making it a widespread concern across various deployment scenarios including corporate networks, public web services, and personal computing environments.
Security professionals should immediately implement mitigation strategies including updating to Konqueror versions that address this vulnerability, which typically involves upgrading to KDE 3.2.3 or later releases that contain proper input sanitization measures. Organizations should also consider implementing network-level restrictions that prevent access to potentially malicious web content, particularly when users are required to interact with untrusted websites. The vulnerability aligns with CWE-74 standards for improper neutralization of special elements in output used by a downstream component, specifically targeting the improper handling of command-line arguments. From an ATT&CK framework perspective, this vulnerability maps to techniques involving command injection and privilege escalation, with potential for lateral movement and persistence within compromised environments. System administrators should also consider implementing additional security controls such as application whitelisting, input validation at multiple layers, and monitoring for unusual command execution patterns that could indicate exploitation attempts. The remediation process requires not only software updates but also comprehensive security awareness training to help users recognize and avoid potentially malicious web content that could trigger this vulnerability.