CVE-2000-0064 in Contivity
Summary
by MITRE
cgiproc CGI script in Nortel Contivity HTTP server allows remote attackers to cause a denial of service via a malformed URL that includes shell metacharacters.
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Analysis
by VulDB Data Team • 04/20/2026
The CVE-2000-0064 vulnerability represents a critical security flaw in the Nortel Contivity HTTP server's cgiproc CGI script that enables remote attackers to execute denial of service attacks through carefully crafted malformed URLs containing shell metacharacters. This vulnerability specifically targets the server's handling of input parameters within the CGI script execution environment, creating a pathway for malicious actors to disrupt legitimate service availability.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the cgiproc CGI script component of the Nortel Contivity HTTP server. When the server processes a malformed URL containing shell metacharacters, the CGI script fails to properly sanitize or escape these special characters before passing them to underlying shell commands. This improper handling creates a classic command injection scenario where attacker-controlled input can be interpreted and executed as shell commands by the operating system. The vulnerability operates at the intersection of CGI script execution and shell command processing, making it particularly dangerous as it can potentially escalate to arbitrary code execution depending on the server's configuration and privileges.
From an operational impact perspective, this vulnerability allows attackers to cause a complete denial of service to the affected HTTP server by triggering abnormal program termination or resource exhaustion through malformed URL requests. The attack vector is particularly insidious because it requires minimal sophistication to execute, making it accessible to attackers with basic knowledge of web application exploitation techniques. The vulnerability affects the availability aspect of the CIA triad by preventing legitimate users from accessing services hosted on the compromised server, potentially disrupting business operations and communication services that depend on the Nortel Contivity platform.
The exploitation of this vulnerability aligns with several ATT&CK framework techniques including T1203 (Exploitation for Client Execution) and T1499 (Endpoint Denial of Service) as it leverages a software vulnerability to disrupt service availability. From a CWE perspective, this represents a variant of CWE-77 and CWE-78, which focus on command injection vulnerabilities where user-supplied data is improperly incorporated into shell commands. The vulnerability also demonstrates characteristics of CWE-20, Input Validation, as the system fails to properly validate and sanitize user input before processing. Organizations running Nortel Contivity servers were particularly vulnerable to this attack as it exploited fundamental security weaknesses in the server's CGI processing mechanism without requiring authentication or advanced exploitation techniques.
Mitigation strategies for CVE-2000-0064 involve implementing proper input validation and sanitization measures within the CGI script processing logic, ensuring that all user-supplied parameters are properly escaped or filtered before being passed to shell commands. System administrators should apply available vendor patches and updates as soon as they become available, while also implementing network-level restrictions to limit access to CGI scripts and monitoring for suspicious URL patterns. The implementation of web application firewalls and input validation rules can provide additional protection layers against similar vulnerabilities in the future, though the most effective approach remains the immediate application of official security patches to address the root cause of the issue.