CVE-1999-1155 in Mail List CGI Script
Summary
by MITRE
LakeWeb Mail List CGI script allows remote attackers to execute arbitrary commands via shell metacharacters in the recipient email address.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability described in CVE-1999-1155 represents a critical command injection flaw within the LakeWeb Mail List CGI script that was prevalent in web-based email list management systems during the late 1990s era. This vulnerability falls under the CWE-77 category of Command Injection, which is a well-documented weakness in software applications where user-supplied input is directly incorporated into system commands without proper sanitization or validation. The specific implementation flaw existed within the handling of recipient email addresses in the CGI script, where the application failed to properly escape or filter special shell metacharacters that could be interpreted by the underlying operating system shell.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious recipient email address containing shell metacharacters such as semicolons, ampersands, or backticks that are then passed directly to the system command execution layer. When the CGI script processes this input without proper sanitization, these metacharacters are interpreted by the shell as command separators or operators, allowing the attacker to inject arbitrary commands that execute with the privileges of the web server process. This represents a classic example of improper input validation and output encoding, where the application assumes that user input will always be benign and fails to implement proper security controls to prevent malicious code execution.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with potential access to sensitive system resources and data that could be used for further compromise. The vulnerability is particularly dangerous in multi-tenant environments where the web server might have elevated privileges, as successful exploitation could lead to complete system compromise, data exfiltration, or the establishment of persistent backdoors. The attack surface is relatively broad since email address fields are commonly used in web applications, making this type of vulnerability particularly prevalent in legacy systems that were not designed with security in mind. This vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as it enables attackers to execute arbitrary commands and potentially escalate their access level within the compromised system.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and sanitization measures, including the use of allow-list validation for email addresses and proper escaping of shell metacharacters when system commands are executed. Organizations should implement parameterized command execution where user input is never directly concatenated into system commands, but rather passed as discrete parameters to prevent shell interpretation. The fix should include comprehensive testing to ensure that all user-supplied input is properly validated and that no special characters can be interpreted by the shell. Additionally, implementing proper access controls and privilege separation ensures that even if exploitation occurs, the impact is limited to the specific privileges of the web server process rather than full system compromise. This vulnerability serves as a prime example of why input validation and proper security design principles must be implemented from the earliest stages of software development, particularly in web applications that interact with system-level processes.