CVE-2002-2094 in Hellbent
Summary
by MITRE
Joe Testa hellbent 01 allows remote attackers to determine the full path of the web root directory via a GET request with a relative path that includes the root s parent, which generates a 403 error message if the parent is incorrect, but a normal response if the parent is correct.
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Analysis
by VulDB Data Team • 08/30/2025
This vulnerability represents a classic path traversal attack that exploits improper input validation in web applications. The flaw exists in the way the application handles relative path requests, specifically when users attempt to access directories through malformed URL structures. When an attacker submits a GET request containing a relative path that references the web root directory's parent directory, the application's response behavior reveals critical information about the server's file structure. The vulnerability operates under the principle that incorrect parent directory references generate a 403 forbidden error, while correct references produce normal responses, creating a binary indicator that can be exploited to map the target server's directory hierarchy. This type of information disclosure vulnerability falls under the category of improper input validation and path traversal attacks, which are commonly categorized under CWE-22 and CWE-23 in the Common Weakness Enumeration framework.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with foundational knowledge necessary for more sophisticated attacks. Once the web root directory path is determined, attackers can potentially access sensitive files, configuration data, or even execute arbitrary code depending on the server's configuration and the application's file permissions. The vulnerability demonstrates a fundamental flaw in the application's security design where error responses inadvertently reveal system information that should remain hidden from unauthorized users. This type of attack pattern aligns with techniques described in the MITRE ATT&CK framework under the T1083 reconnaissance technique, where adversaries gather information about the target system's file structure and directory hierarchy.
The technical implementation of this attack relies on the predictable response behavior of the web application when handling malformed path requests. When the application encounters a request that references a parent directory of the web root, it returns different HTTP responses based on whether the path traversal is valid or invalid. This differential response mechanism creates a timing-based side channel that attackers can exploit to enumerate directory structures through systematic trial and error. The vulnerability is particularly dangerous because it requires minimal input and leverages the application's natural error handling mechanisms to provide attackers with the information needed to plan further attacks. Security professionals should note that this vulnerability type often indicates broader architectural issues in how applications handle user input and manage file system access controls.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and sanitization mechanisms that prevent path traversal attempts before they reach the file system layer. The recommended approach includes normalizing all user input to prevent directory traversal sequences, implementing strict access controls that limit file system access to only necessary resources, and ensuring that error messages do not reveal internal system information. Organizations should also consider implementing web application firewalls that can detect and block suspicious path traversal patterns, as well as regular security testing that includes automated scanning for similar vulnerabilities. The fix should ensure that all directory traversal attempts are properly validated and that error responses are generic and do not provide information about the underlying file system structure. Additionally, implementing proper logging and monitoring for unusual directory access patterns can help detect exploitation attempts and provide early warning of potential attacks.