CVE-2005-3094 in Man Cgi
Summary
by MITRE
Avi Alkalay man-cgi script allows remote attackers to execute arbitrary code via shell metacharacters in the topic parameter.
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Analysis
by VulDB Data Team • 06/09/2019
The vulnerability identified as CVE-2005-3094 affects the man-cgi script developed by Avi Alkalay, which represents a critical security flaw in web-based documentation systems. This issue resides within the script's handling of user input parameters, specifically the topic parameter that is used to specify which manual page or documentation topic should be displayed. The vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly escape or filter shell metacharacters, creating an avenue for malicious exploitation.
The technical flaw manifests when an attacker crafts a malicious payload containing shell metacharacters such as semicolons, ampersands, or backticks within the topic parameter of the man-cgi script. These metacharacters are interpreted by the underlying shell when the script processes the input, leading to unintended command execution on the target system. This represents a classic command injection vulnerability where user-controllable input directly influences shell command execution without proper sanitization. The vulnerability is categorized under CWE-78 as "Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')", which is a well-documented weakness in software systems that process user input through shell commands.
The operational impact of this vulnerability is severe as it allows remote attackers to execute arbitrary code on the affected system with the privileges of the web server process. An attacker could potentially gain full control over the server, execute system commands, access sensitive data, or establish persistent backdoors. The remote nature of the attack means that exploitation does not require local system access, making it particularly dangerous for web-facing systems. This vulnerability could be leveraged to perform reconnaissance activities, escalate privileges, or launch further attacks against internal network resources. The attack surface is broad as the vulnerability affects any system running the vulnerable man-cgi script, particularly those used for hosting documentation or manual pages accessible via web interfaces.
Mitigation strategies for CVE-2005-3094 should focus on implementing proper input validation and sanitization techniques. The primary defense involves ensuring that all user-supplied input is properly escaped or filtered before being processed by shell commands. This can be achieved through input validation that rejects or encodes special characters, or by using safe API functions that do not invoke shell commands directly. Organizations should consider implementing proper parameterized queries or command execution methods that prevent shell interpretation of user input. Additionally, the principle of least privilege should be enforced by running web server processes with minimal required permissions, and regular security audits should be conducted to identify and remediate similar vulnerabilities. The ATT&CK framework categorizes this vulnerability under T1059.001 "Command and Scripting Interpreter: Shell Script", which emphasizes the importance of preventing command injection attacks through proper input handling and validation measures. System administrators should also implement network segmentation and monitoring to detect suspicious command execution patterns that may indicate exploitation attempts.