CVE-2001-1023 in Xcache
Summary
by MITRE
Xcache 2.1 allows remote attackers to determine the absolute path of web server documents by requesting a URL that is not cached by Xcache, which returns the full pathname in the Content-PageName header.
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Analysis
by VulDB Data Team • 06/04/2018
The vulnerability described in CVE-2001-1023 affects Xcache version 2.1, a caching module for web servers that operates as a transparent proxy to improve performance by storing frequently accessed content. This flaw represents a significant information disclosure issue that exposes the underlying file system structure of web servers to remote attackers. The vulnerability specifically manifests when Xcache processes requests for URLs that are not present in its cache, creating an opportunity for adversaries to extract sensitive path information from server responses.
The technical mechanism behind this vulnerability involves the Content-PageName header that Xcache includes in its response headers when serving uncached content. When a remote attacker requests a non-existent URL or a resource that Xcache has not cached, the module inadvertently returns the absolute file path where it attempted to locate the requested resource. This behavior occurs because Xcache fails to sanitize or obscure the internal path resolution process that happens during request handling. The flaw essentially creates a side-channel information leak that reveals the server's document root directory structure and the specific file paths used by the web server.
From an operational perspective, this vulnerability poses a serious risk to web server security as it provides attackers with crucial information for subsequent exploitation attempts. The disclosed absolute paths can be used to map the web server's directory structure, potentially revealing sensitive files, configuration data, or application source code that might otherwise remain hidden from public view. Attackers can leverage this information to craft more targeted attacks, including directory traversal exploits, file inclusion vulnerabilities, or to identify specific application components that may have additional security weaknesses. The vulnerability particularly affects systems where Xcache is deployed in production environments without proper security hardening measures.
The security implications of this vulnerability align with CWE-200, which describes information exposure through improper error handling or information leakage in software systems. This classification specifically addresses scenarios where applications inadvertently reveal sensitive information that could be exploited by attackers. The vulnerability also intersects with ATT&CK technique T1083, which covers directory and file discovery, as attackers can use the leaked path information to enumerate server resources systematically. Organizations using Xcache 2.1 should consider implementing network segmentation, access control restrictions, and proper input validation to prevent unauthorized access to sensitive path information.
The remediation approach for this vulnerability requires immediate patching of the Xcache module to version 2.2 or later, where the issue has been addressed through proper header sanitization and path obfuscation. Additionally, administrators should implement proper logging and monitoring to detect suspicious requests that might attempt to exploit this vulnerability. Network-level controls such as firewalls and intrusion detection systems can be configured to block or alert on requests that trigger the information disclosure behavior. The vulnerability serves as a reminder of the importance of secure coding practices and the need for thorough security testing of web server components, particularly those that operate at the network level and handle file system operations.