CVE-1999-0983 in Whois Lookup
Summary
by MITRE
Whois Internic Lookup program whois.cgi allows remote attackers to execute commands via shell metacharacters in the domain entry.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability identified as CVE-1999-0983 represents a critical command injection flaw in the Whois Internic Lookup program whois.cgi component. This issue stems from inadequate input validation within the web-based interface that processes domain lookup requests. The vulnerability specifically affects the whois.cgi script which serves as an intermediary between user requests and the underlying whois database queries, creating a pathway for malicious actors to manipulate the system through crafted input parameters.
The technical exploitation mechanism relies on the program's failure to properly sanitize user-supplied domain names before incorporating them into shell commands. When a user enters a domain name into the whois lookup interface, the script constructs a shell command that includes the user input without appropriate escaping or filtering of special shell metacharacters such as semicolons, ampersands, backticks, or pipe characters. This allows attackers to inject arbitrary shell commands that execute with the privileges of the web server process, typically running under the system's root or administrative account.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with full control over the affected system. Successful exploitation can result in complete system compromise, data exfiltration, privilege escalation, and potential lateral movement within network environments. The vulnerability affects systems where the whois.cgi script is deployed and accessible via web interface, making it particularly dangerous in publicly exposed web applications that provide domain lookup services.
This vulnerability aligns with CWE-77 and CWE-94 categories within the Common Weakness Enumeration framework, specifically representing a command injection flaw that allows arbitrary code execution. The ATT&CK framework categorizes this under T1059.001 for Command and Scripting Interpreter with shell command execution, and potentially T1068 for Exploitation for Privilege Escalation when the web server process operates with elevated privileges. The vulnerability demonstrates a classic lack of input validation and output encoding, common patterns in web application security that have persisted across decades of software development practices.
Mitigation strategies for CVE-1999-0983 require immediate implementation of proper input sanitization and parameter validation. Organizations should ensure that all user-supplied input undergoes strict filtering to remove or escape shell metacharacters before processing. The recommended approach includes implementing whitelisting mechanisms that only allow legitimate domain name characters, utilizing secure library functions for shell command execution, and employing proper input validation frameworks. Additionally, system administrators should consider removing or disabling the vulnerable whois.cgi functionality if it is not essential, and implement web application firewalls to detect and block malicious input patterns. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other web applications, as command injection flaws remain prevalent in legacy systems and improperly configured web interfaces.