CVE-2005-3096 in nslookup.cgi
Summary
by MITRE
Avi Alkalay nslookup.cgi program, dated 16 June 2002, allows remote attackers to execute arbitrary commands via shell metacharacters in the query parameter.
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Analysis
by VulDB Data Team • 07/11/2024
The vulnerability identified as CVE-2005-3096 affects the nslookup.cgi program developed by Avi Alkalay and released on June 16, 2002. This web-based utility is designed to perform DNS lookups through a web interface, making it accessible to users who need to query DNS information without direct command-line access. The program's interface allows users to submit DNS query parameters through HTTP requests, which are then processed by the underlying system. However, the implementation contains a critical security flaw that allows malicious actors to bypass normal input validation and execute arbitrary commands on the target system. The vulnerability stems from insufficient sanitization of user-supplied input, specifically the query parameter that is passed directly to shell commands without proper filtering or escaping mechanisms. This design flaw creates an environment where attackers can inject shell metacharacters such as semicolons, ampersands, or backticks into the query parameter, which are then interpreted and executed by the system shell. The vulnerability represents a classic command injection flaw that enables remote code execution, allowing attackers to perform actions with the privileges of the web server process. This type of vulnerability falls under CWE-77 which specifically addresses command injection flaws in software systems. The security implications extend beyond simple code execution as attackers can leverage this vulnerability to gain persistent access to the system, escalate privileges, or use the compromised server as a launching point for further attacks within the network infrastructure.
The operational impact of CVE-2005-3096 is significant and potentially catastrophic for any organization running the affected nslookup.cgi program. Remote attackers can exploit this vulnerability to execute arbitrary commands on the target system, potentially gaining full control over the web server and its underlying operating system. The vulnerability allows for privilege escalation, enabling attackers to access sensitive data, modify system configurations, or establish backdoors for persistent access. The attack surface is particularly concerning because the vulnerability can be exploited through simple HTTP requests without requiring authentication or specialized tools. This makes the vulnerability highly attractive to automated attack scripts and malicious actors who can scan for vulnerable systems and exploit them at scale. The affected system could be used as a pivot point for attacking internal network resources, making it a valuable target for attackers seeking to expand their foothold within an organization's infrastructure. The vulnerability also enables attackers to perform reconnaissance activities, gather system information, and potentially deploy additional malware or tools to further compromise the environment. From an attack perspective, this vulnerability aligns with techniques described in the attack pattern taxonomy under the MITRE ATT&CK framework where adversaries leverage command injection to execute malicious code and maintain persistence.
Mitigation strategies for CVE-2005-3096 require immediate action to address the core command injection flaw in the nslookup.cgi program. The most effective approach involves implementing proper input validation and sanitization mechanisms that prevent shell metacharacters from being interpreted as commands. This can be achieved through the use of parameterized queries, input filtering, and proper escaping of special characters before any system calls are made. Organizations should also consider implementing web application firewalls that can detect and block malicious payloads attempting to exploit command injection vulnerabilities. The recommended solution involves rewriting the vulnerable code to avoid direct shell command execution with user input, instead implementing safer methods for DNS resolution such as using dedicated DNS libraries or APIs. Additionally, system administrators should ensure that the affected program is either updated to a secure version, removed from production environments, or properly isolated within a secure network segment. Security hardening measures should include restricting file permissions, implementing least privilege principles, and ensuring that the web server process runs with minimal required privileges. Regular security assessments and vulnerability scanning should be conducted to identify similar flaws in other applications and scripts that may be vulnerable to the same class of attack. The vulnerability also highlights the importance of secure coding practices and proper input validation as outlined in industry standards and best practices for preventing injection attacks.