CVE-2001-0025 in ad.cgi
Summary
by MITRE
ad.cgi CGI program by Leif Wright allows remote attackers to execute arbitrary commands via shell metacharacters in the file parameter.
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Analysis
by VulDB Data Team • 07/19/2024
The vulnerability described in CVE-2001-0025 represents a critical command injection flaw in the ad.cgi CGI program developed by Leif Wright. This vulnerability exists within web server applications that utilize CGI scripts for handling user input and processing requests. The specific flaw manifests when the program fails to properly validate or sanitize user-supplied data passed through the file parameter, creating an opportunity for malicious actors to execute arbitrary system commands on the affected server. The vulnerability is classified under CWE-77 as "Improper Neutralization of Special Elements used in a Command ('Command Injection')", which directly aligns with the ATT&CK technique T1059.001 for Command and Scripting Interpreter.
The technical implementation of this vulnerability occurs when the ad.cgi script processes the file parameter without adequate input sanitization measures. When a remote attacker submits shell metacharacters such as semicolons, ampersands, or backticks within the file parameter, these characters are interpreted by the underlying shell executing the CGI script. This allows attackers to append additional commands to the original execution flow, effectively bypassing normal access controls and gaining unauthorized system-level privileges. The vulnerability is particularly dangerous because it enables complete system compromise, allowing attackers to read, modify, or delete files, install malware, or establish persistent backdoors on the affected system.
From an operational perspective, this vulnerability presents a severe threat to web server security and can result in complete system compromise. Organizations running affected versions of the ad.cgi program face significant risks including data breaches, service disruption, and potential regulatory compliance violations. The attack vector is straightforward requiring only basic web browser access to exploit the vulnerability. Once exploited, attackers can leverage this initial access to perform reconnaissance activities, escalate privileges, and move laterally within the network infrastructure. This vulnerability also demonstrates poor security practices in input validation and output encoding that were common in web applications of that era, highlighting the importance of implementing proper security controls.
Mitigation strategies for this vulnerability should include immediate patching of the affected ad.cgi script to implement proper input validation and sanitization mechanisms. Organizations must ensure that all user-supplied input is properly escaped or filtered before being processed by the system shell. The implementation of a web application firewall can provide additional protection by detecting and blocking suspicious command injection patterns. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other CGI scripts or web applications. Additionally, system administrators should implement proper access controls and monitoring to detect unauthorized command execution attempts. This vulnerability underscores the fundamental importance of following secure coding practices and adheres to the principle of least privilege as outlined in various cybersecurity frameworks including NIST SP 800-53 and ISO 27001 standards.