CVE-2000-0671 in Webserver
Summary
by MITRE
Roxen web server earlier than 2.0.69 allows allows remote attackers to bypass access restrictions, list directory contents, and read source code by inserting a null character (%00) to the URL.
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Analysis
by VulDB Data Team • 10/13/2025
The vulnerability identified as CVE-2000-0671 represents a critical security flaw in the Roxen web server software affecting versions prior to 2.0.69. This issue stems from inadequate input validation mechanisms within the web server's URL processing functionality, creating a pathway for remote attackers to exploit the system through crafted malicious requests. The vulnerability specifically manifests when the web server fails to properly sanitize URL parameters containing null characters, which are typically used as string terminators in many programming languages and operating systems.
The technical exploitation of this vulnerability occurs through the insertion of null character sequences %00 into URLs, which allows attackers to manipulate the web server's internal processing routines. When the Roxen server encounters such malformed URLs, it does not properly handle the null termination character, leading to unexpected behavior in the file system access controls. This flaw enables unauthorized access to protected resources, directory traversal capabilities, and source code disclosure that should remain restricted to authorized users only. The underlying mechanism exploits weaknesses in the server's input validation and string handling processes, which are fundamental security controls that should prevent such manipulations.
From an operational impact perspective, this vulnerability creates severe consequences for organizations relying on the affected Roxen web server versions. Attackers can leverage this weakness to bypass authentication mechanisms entirely, gaining access to sensitive directories containing application source code, configuration files, and potentially user data. The ability to list directory contents provides attackers with valuable reconnaissance information, while source code disclosure can reveal implementation details that facilitate further exploitation. This vulnerability directly violates security principles of least privilege and access control, allowing unauthorized users to access resources they should not be permitted to view or modify. The impact extends beyond simple information disclosure, as source code exposure can reveal implementation flaws, hardcoded credentials, and other sensitive information that could be used for additional attacks.
The vulnerability aligns with CWE-170, which addresses issues related to improper handling of null terminators in strings, and represents a classic example of input validation failure in web server implementations. From an attacker's perspective, this flaw maps to techniques described in the ATT&CK framework under the T1190 - Exploit Public-Facing Application tactic, where adversaries target vulnerabilities in web applications to gain unauthorized access. Organizations using affected versions of Roxen should immediately implement mitigation strategies including upgrading to version 2.0.69 or later, implementing proper input validation at the web server level, and configuring additional access controls. Network segmentation and monitoring solutions should be deployed to detect and prevent exploitation attempts. The vulnerability also highlights the importance of regular security assessments and patch management procedures to prevent similar issues from affecting other web server implementations. Organizations should consider implementing web application firewalls and additional security controls to protect against similar null byte injection attacks that may affect other software components.