CVE-2001-0180 in Guestserver
Summary
by MITRE
Lars Ellingsen guestserver.cgi allows remote attackers to execute arbitrary commands via shell metacharacters in the "email" parameter.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 05/20/2019
The vulnerability described in CVE-2001-0180 represents a critical command injection flaw in the guestserver.cgi web application developed by Lars Ellingsen. This cgi script, typically used for handling guest book entries or similar web forms, suffers from a fundamental security oversight that allows remote attackers to execute arbitrary system commands on the affected server. The vulnerability specifically manifests when the application fails to properly sanitize user input submitted through the email parameter, creating an exploitable condition that directly impacts system integrity and confidentiality.
The technical flaw resides in the application's insufficient input validation and output sanitization mechanisms. When a user submits data through the email parameter, the guestserver.cgi script processes this input without adequate filtering or escaping of shell metacharacters such as semicolons, ampersands, backticks, or pipes. This lack of proper input sanitization creates a direct path for attackers to inject malicious shell commands that get executed within the context of the web server process. The vulnerability maps directly to CWE-77, which specifically addresses command injection flaws where untrusted data is incorporated into shell commands without proper validation or escaping, making it a clear example of insecure coding practices that have been documented in security literature for decades.
The operational impact of this vulnerability extends far beyond simple data theft or service disruption. Successful exploitation allows attackers to gain arbitrary code execution privileges on the target system, potentially enabling them to escalate their access to full system compromise. Attackers can leverage this vulnerability to execute commands such as system file enumeration, privilege escalation, data exfiltration, or even establish persistent backdoors. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring physical access or prior authentication, making it particularly dangerous for web applications that handle sensitive user data. From an attacker's perspective, this vulnerability aligns with techniques described in the attack phase of the kill chain, specifically targeting the execution and privilege escalation stages as outlined in the MITRE ATT&CK framework.
Mitigation strategies for CVE-2001-0180 require immediate implementation of proper input validation and sanitization measures. Organizations should ensure that all user-supplied data is properly escaped or filtered before being processed by any system commands or shell invocations. The recommended approach involves implementing strict input validation that rejects or sanitizes potentially dangerous characters and sequences, while also employing parameterized queries where possible. Additionally, the principle of least privilege should be applied by running web server processes with minimal required permissions, limiting the potential damage from successful exploitation. System administrators should also implement proper monitoring and logging mechanisms to detect unusual command execution patterns that may indicate exploitation attempts. The vulnerability underscores the importance of input validation as a fundamental security control, representing a classic example of how basic security practices can prevent widespread compromise of web applications and the systems they operate on.