CVE-2000-0878 in Mailto CGI Script
Summary
by MITRE
The mailto CGI script allows remote attacker to execute arbitrary commands via shell metacharacters in the emailadd form field.
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Analysis
by VulDB Data Team • 09/11/2017
The vulnerability identified as CVE-2000-0878 represents a critical command injection flaw in the mailto CGI script that enables remote attackers to execute arbitrary system commands on the affected server. This vulnerability falls under the category of insecure input handling and improper output encoding, specifically targeting web applications that process user-supplied data through CGI interfaces. The mailto CGI script, designed to facilitate email functionality on web servers, fails to properly sanitize user input, creating an avenue for malicious actors to inject shell metacharacters into the emailadd form field. When the application processes this unvalidated input, it directly incorporates the user-supplied data into shell commands without adequate sanitization or escaping mechanisms, thereby allowing attackers to manipulate the command execution flow.
The technical exploitation of this vulnerability occurs when an attacker submits specially crafted input containing shell metacharacters such as semicolons, ampersands, or backticks into the emailadd form field. These metacharacters are interpreted by the underlying shell as command separators or operators, enabling the attacker to append additional commands to the intended mailto functionality. The vulnerability stems from the lack of proper input validation and output encoding, creating a classic command injection attack vector that operates at the system level rather than at the application layer. This flaw directly maps to CWE-77 which describes improper neutralization of special elements used in a command, and represents a fundamental breakdown in secure coding practices related to shell command construction.
The operational impact of CVE-2000-0878 is severe and encompasses complete system compromise, data exfiltration, and potential lateral movement within affected networks. Successful exploitation allows attackers to execute arbitrary commands with the privileges of the web server process, which typically runs with elevated permissions on the target system. This can lead to unauthorized access to sensitive data, system file manipulation, privilege escalation to root or administrator accounts, and the installation of persistent backdoors or malware. The vulnerability also provides attackers with the ability to perform reconnaissance activities, such as enumerating system information, scanning network ports, and accessing other services running on the compromised host. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation, making it particularly dangerous for attackers seeking to maintain persistent access and expand their operational capabilities.
Mitigation strategies for CVE-2000-0878 must address both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities from emerging in the future. The primary remediation involves implementing proper input validation and output encoding mechanisms that sanitize all user-supplied data before it is processed by the application. This includes escaping special shell metacharacters, implementing allowlists for valid input patterns, and using parameterized command execution instead of direct string concatenation. Organizations should also implement proper access controls and privilege separation, ensuring that web applications run with minimal necessary privileges. Additionally, regular security assessments, code reviews focusing on input validation, and deployment of web application firewalls can provide defense-in-depth measures. The vulnerability highlights the importance of following secure coding practices and adheres to principles outlined in OWASP Top Ten and NIST Cybersecurity Framework, emphasizing the need for comprehensive application security controls that address both the immediate threat and prevent similar command injection vulnerabilities from reoccurring in other components of the system architecture.