CVE-2004-1468 in Webmin
Summary
by MITRE
The web mail functionality in Usermin 1.x and Webmin 1.x allows remote attackers to execute arbitrary commands via shell metacharacters in an e-mail message.
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Analysis
by VulDB Data Team • 06/30/2021
The vulnerability identified as CVE-2004-1468 represents a critical command injection flaw within the web mail functionality of Usermin and Webmin versions 1.x. This vulnerability arises from insufficient input validation and sanitization within the email processing components of these web-based system administration tools. The flaw specifically manifests when the system processes incoming email messages that contain shell metacharacters, which are typically used to execute system commands in Unix-like operating systems. The vulnerability exists because the email handling code fails to properly escape or filter special characters that could be interpreted by the underlying shell when processing email content.
The technical implementation of this vulnerability stems from improper handling of user-supplied data within the mail processing pipeline. When an attacker sends an email message containing shell metacharacters such as semicolons, ampersands, or backticks, the web application does not adequately sanitize this input before using it in system calls or shell commands. This allows an attacker to inject malicious commands that are then executed with the privileges of the web server process. The vulnerability is classified under CWE-77 as "Improper Neutralization of Special Elements used in a Command ('Command Injection')", which is a well-documented weakness in software security practices. The attack vector operates entirely through the web interface, making it accessible to remote attackers without requiring local system access or authentication to the underlying system.
The operational impact of this vulnerability is severe and far-reaching for organizations using affected versions of Usermin or Webmin. An attacker who successfully exploits this vulnerability can execute arbitrary commands on the target system, potentially gaining full control over the server. This includes the ability to read sensitive files, modify system configurations, install malware, create backdoors, or escalate privileges to root access. The vulnerability affects the core functionality of these administration tools, which are commonly used for managing user accounts, system configurations, and network services. Given that these tools are often accessible from the internet and may be running with elevated privileges, the potential for system compromise is significant. The attack can be executed without authentication, making it particularly dangerous as it can be exploited by anyone with access to the web interface.
Organizations should immediately implement multiple layers of mitigation strategies to address this vulnerability. The primary and most effective solution involves upgrading to patched versions of Usermin and Webmin where the input sanitization has been properly implemented. Security patches typically include enhanced input validation, proper shell escaping mechanisms, and stricter sanitization of email content before processing. Additionally, network-level defenses should be implemented including firewall rules that restrict access to the web administration interfaces, particularly from untrusted networks. The principle of least privilege should be enforced by ensuring that webmin and usermin services run with minimal required permissions and that access is restricted to authorized personnel only. Network segmentation can help isolate these administrative interfaces from general user access, reducing the attack surface. Regular security audits and monitoring of system logs should be conducted to detect any potential exploitation attempts. The vulnerability demonstrates the critical importance of input validation in web applications and aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, highlighting how insecure input handling can lead to complete system compromise. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor for malicious payloads containing shell metacharacters that could indicate exploitation attempts.