CVE-2000-1206 in HTTP Server
Summary
by MITRE
Vulnerability in Apache httpd before 1.3.11, when configured for mass virtual hosting using mod_rewrite, or mod_vhost_alias in Apache 1.3.9, allows remote attackers to retrieve arbitrary files.
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Analysis
by VulDB Data Team • 10/11/2025
The vulnerability identified as CVE-2000-1206 represents a critical directory traversal flaw in the Apache HTTP Server version 1.3.10 and earlier, particularly affecting configurations that utilize mass virtual hosting through mod_rewrite or mod_vhost_alias modules. This security weakness stems from inadequate input validation within the server's handling of virtual host configurations, creating a path traversal condition that enables unauthorized access to files outside the intended document root directories. The vulnerability specifically manifests when Apache is configured to handle multiple virtual hosts dynamically, making it particularly dangerous in shared hosting environments or scenarios where administrators rely on these modules for flexible web hosting solutions. The flaw exists at the core of how Apache processes rewrite rules and virtual host mappings, allowing attackers to craft malicious requests that bypass normal access controls and retrieve sensitive files from the server's file system.
The technical implementation of this vulnerability exploits the way Apache processes URL rewriting and virtual host resolution when these modules are enabled. Attackers can manipulate the request URI through carefully crafted rewrite rules or virtual host aliases to traverse directory structures and access files that should otherwise be restricted. This typically involves constructing specific URL patterns that cause Apache to resolve paths incorrectly, allowing access to system files, configuration files, or other sensitive data that resides outside the normal web root boundaries. The vulnerability is particularly insidious because it operates at the HTTP server level rather than application level, making it difficult to detect through traditional application security measures. The flaw is categorized under CWE-22 as "Improper Limitation of a Pathname to a Restricted Directory" and aligns with ATT&CK technique T1566.001 for "Phishing with Social Engineering" and T1071.004 for "Application Layer Protocol: DNS" in its exploitation methods. The vulnerability affects the core functionality of Apache's virtual hosting capabilities and demonstrates how module-based configurations can introduce unexpected security weaknesses.
The operational impact of CVE-2000-1206 extends far beyond simple unauthorized file access, as it provides attackers with potential access to critical system information that could lead to further exploitation. An attacker who successfully exploits this vulnerability can retrieve sensitive files such as password hashes, configuration files containing database credentials, or system files that might reveal the server's operating system details and installed software versions. This information can serve as a foundation for more sophisticated attacks including privilege escalation, lateral movement within the network, or the discovery of additional vulnerabilities. The vulnerability is particularly concerning in environments where Apache serves multiple virtual hosts with different security contexts, as it could allow an attacker to access files belonging to other tenants in shared hosting scenarios. The impact is amplified when considering that the vulnerability affects Apache versions that were widely deployed in production environments, making it a significant threat vector for organizations that had not yet updated their server configurations. Organizations using mod_rewrite or mod_vhost_alias modules in their Apache installations were particularly at risk, as these modules were commonly used for flexible web hosting configurations.
Mitigation strategies for CVE-2000-1206 focus primarily on immediate software updates and configuration hardening. The most effective remediation involves upgrading to Apache HTTP Server version 1.3.11 or later, where the vulnerability has been addressed through improved path validation in the virtual hosting modules. Administrators should also implement strict input validation for rewrite rules and virtual host configurations, ensuring that all path references are properly sanitized and constrained to predefined safe directories. The use of the mod_security module or similar web application firewalls can provide additional protection layers by monitoring and filtering suspicious request patterns that might attempt to exploit the vulnerability. Configuration reviews should include examining all mod_rewrite and mod_vhost_alias directives to ensure they do not allow arbitrary path traversal or permit access to sensitive system directories. Network-level mitigations such as implementing proper access controls and limiting direct server access can also reduce the attack surface. Organizations should also consider implementing monitoring and logging mechanisms to detect unusual access patterns that might indicate exploitation attempts, as the vulnerability could be used as part of broader attack campaigns targeting web servers. The vulnerability serves as a reminder of the importance of keeping web server software up to date and the potential risks associated with complex module configurations that extend beyond basic web serving functionality.