CVE-2000-0370 in OpenLinux
Summary
by MITRE
The debug option in Caldera Linux smail allows remote attackers to execute commands via shell metacharacters in the -D option for the rmail command.
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Analysis
by VulDB Data Team • 04/18/2026
The vulnerability described in CVE-2000-0370 resides within the Caldera Linux distribution's implementation of the smail mail transfer agent, specifically in how it handles the debug option. This flaw represents a classic command injection vulnerability that arises from inadequate input sanitization within the mail handling system. The vulnerability manifests when the rmail command is invoked with the -D option, which is intended for debugging purposes but becomes a vector for arbitrary command execution due to insufficient validation of user-supplied parameters.
The technical exploitation of this vulnerability occurs through the manipulation of shell metacharacters within the debug option parameter. When an attacker provides malicious input containing shell metacharacters such as semicolons, ampersands, or command substitution operators, these characters are interpreted by the underlying shell process that executes the debug functionality. This creates a path for remote attackers to execute arbitrary commands with the privileges of the mail daemon process, potentially leading to full system compromise. The vulnerability operates at the level of command line argument processing where user input is directly concatenated into shell execution contexts without proper sanitization or escaping mechanisms.
From an operational perspective, this vulnerability presents a significant risk to systems running Caldera Linux with the smail mail agent, as it allows remote attackers to execute commands without authentication. The impact extends beyond simple privilege escalation to include potential data exfiltration, system reconnaissance, and further lateral movement within compromised networks. The vulnerability is particularly dangerous because it leverages legitimate debugging functionality that is often enabled in production environments, making it difficult to detect and mitigate through normal security monitoring. The attack surface is expanded by the fact that the rmail command is typically accessible to unauthenticated users, providing attackers with an easy entry point.
The vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a direct violation of secure coding practices for input validation and sanitization. It also maps to ATT&CK technique T1059.007 for command and scripting interpreter, specifically shell scripting, and T1068 for exploit for privilege escalation. Organizations should implement immediate mitigations including disabling the debug option in production environments, implementing proper input validation and sanitization for all command line arguments, and restricting access to mail services to trusted networks only. Additionally, patching the smail package to properly escape or validate debug option parameters would provide a permanent solution to this vulnerability.