CVE-2000-0422 in DMail
Summary
by MITRE
Buffer overflow in Netwin DMailWeb CGI program allows remote attackers to execute arbitrary commands via a long utoken parameter.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/16/2025
The vulnerability identified as CVE-2000-0422 represents a critical buffer overflow flaw within the Netwin DMailWeb CGI program that exposes systems to remote command execution capabilities. This issue resides in the handling of user-supplied input parameters, specifically the utoken parameter which is processed without adequate bounds checking. The buffer overflow occurs when an attacker submits a carefully crafted payload containing an excessively long utoken value that exceeds the allocated buffer space, causing memory corruption that can be exploited to gain unauthorized system access. The vulnerability affects the web-based email management system component of Netwin DMailWeb, which operates through CGI scripts that process user requests and interact with underlying system resources.
The technical implementation of this vulnerability demonstrates a classic buffer overflow condition where the program fails to validate the length of input data before copying it into a fixed-size memory buffer. When the utoken parameter exceeds the buffer capacity, adjacent memory locations become overwritten, potentially corrupting critical program execution data such as return addresses or function pointers. Attackers can manipulate this memory corruption to redirect program execution flow and inject malicious code that executes with the privileges of the web server process. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which classifies buffer overflow conditions that occur when data is written beyond the boundaries of a fixed-length buffer, and specifically aligns with CWE-78, which addresses improper neutralization of special elements used in OS commands.
The operational impact of this vulnerability extends beyond simple data corruption, as it provides attackers with a pathway to achieve complete system compromise. Remote exploitation allows adversaries to execute arbitrary commands on the vulnerable system, potentially leading to full administrative control over the web server hosting the DMailWeb application. The attack vector requires only a web browser to send a specially crafted HTTP request containing the malicious utoken parameter, making the vulnerability particularly dangerous as it can be exploited from any location without requiring physical access or prior authentication. This characteristic places the vulnerability within the MITRE ATT&CK framework under the technique T1059, which describes executing commands through various interfaces including web applications, and T1203, which involves using web shell techniques to maintain persistent access to compromised systems.
Mitigation strategies for CVE-2000-0422 should prioritize immediate patching of the affected Netwin DMailWeb software to address the buffer overflow condition through proper input validation and bounds checking mechanisms. Organizations should implement input sanitization measures that enforce strict parameter length limits and reject excessively long values before they can be processed by the CGI application. Network segmentation and firewall rules can help limit access to the vulnerable web application while patches are deployed, and intrusion detection systems should be configured to monitor for suspicious HTTP requests containing unusually long parameter values. Additionally, implementing web application firewalls and application-level security controls can provide additional layers of protection against similar buffer overflow vulnerabilities in other web applications. The vulnerability serves as a reminder of the critical importance of proper input validation in web applications and the potential consequences of failing to implement adequate security controls in CGI-based systems.