CVE-2001-0893 in Mini HTTPd
Summary
by MITRE
Acme mini_httpd before 1.16 allows remote attackers to view sensitive files under the document root (such as .htpasswd) via a GET request with a trailing /.
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Analysis
by VulDB Data Team • 04/10/2019
The vulnerability described in CVE-2001-0893 affects the Acme mini_httpd web server software version 1.15 and earlier, representing a critical path traversal flaw that enables unauthorized access to sensitive files within the server's document root directory. This issue arises from improper handling of HTTP GET requests that contain trailing slashes in the requested resource path, allowing attackers to bypass normal access controls and retrieve files that should remain protected. The vulnerability specifically targets the server's directory traversal logic, where the web server fails to properly sanitize or validate the requested paths before serving content, creating an exploitable condition that can be leveraged by remote attackers without authentication.
The technical implementation of this vulnerability stems from the web server's inadequate input validation mechanism when processing HTTP requests containing trailing slashes. When a malicious user submits a GET request with a trailing slash in the resource path, the mini_httpd server fails to properly normalize or sanitize the request before attempting to locate and serve the requested file. This flaw can be exploited to access files such as .htpasswd authentication files, configuration files, source code files, or other sensitive data that resides within the document root directory structure. The vulnerability is particularly dangerous because it allows attackers to bypass normal directory access controls and retrieve files that are typically protected from direct web access, effectively creating a backdoor for information disclosure attacks.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to complete system compromise when attackers gain access to authentication credentials, configuration files, or other sensitive data that can be used for further exploitation. Attackers can leverage this vulnerability to obtain .htpasswd files containing user credentials, which can then be used to authenticate to the web server or other systems that share the same authentication database. Additionally, the exposure of configuration files may reveal internal system information, database connection strings, or other sensitive parameters that can facilitate more sophisticated attacks. The vulnerability affects systems where mini_httpd is deployed as a web server, particularly those that rely on directory-based access controls for protecting sensitive content.
The exploitation of this vulnerability aligns with several tactics outlined in the attack pattern taxonomy, specifically involving information gathering and privilege escalation techniques that are commonly used in cyber attacks. From a cybersecurity perspective, this vulnerability demonstrates the importance of proper input validation and sanitization in web server implementations, as highlighted by CWE-22 which addresses improper limitation of a pathname to a restricted directory. Organizations should implement immediate mitigations including upgrading to mini_httpd version 1.16 or later, which contains the necessary patches to address the directory traversal issue, and implementing additional access controls such as restrictive file permissions and web server configuration modifications. Network-based mitigations can include firewall rules that restrict access to sensitive files and monitoring for suspicious HTTP request patterns that may indicate exploitation attempts, while also ensuring that all systems running mini_httpd are regularly updated to address similar vulnerabilities in the broader software ecosystem.
This vulnerability serves as a reminder of the critical importance of proper web server security configurations and input validation practices, particularly in older software versions where security patches may not be readily available or may not be properly applied. The issue highlights the ongoing challenge of maintaining security in legacy web server implementations and underscores the necessity of regular security assessments to identify and remediate similar path traversal vulnerabilities that may exist in other web server software implementations. Organizations should also consider implementing web application firewalls and security monitoring solutions that can detect and prevent exploitation attempts targeting directory traversal vulnerabilities, while maintaining comprehensive logging and audit trails to track access to sensitive files and identify potential compromise indicators.