CVE-2003-0417 in Son hServer
Summary
by MITRE
Directory traversal vulnerability in Son hServer 0.2 allows remote attackers to read arbitrary files via ".|." (modified dot-dot) sequences.
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Analysis
by VulDB Data Team • 05/17/2019
The directory traversal vulnerability identified in Son hServer version 0.2 represents a critical security flaw that enables remote attackers to access arbitrary files on the affected system through specifically crafted file path sequences. This vulnerability exploits the server's insufficient input validation mechanisms, allowing malicious users to bypass normal file access controls and retrieve sensitive data from the file system. The exploitation technique involves using modified dot-dot sequences such as ".|." which can trick the server into interpreting these paths in unexpected ways, effectively allowing directory traversal beyond the intended document root.
The technical implementation of this vulnerability stems from the server's inadequate sanitization of user-supplied input containing file path references. When the server processes requests containing these modified traversal sequences, it fails to properly validate or normalize the input before resolving file paths. This allows attackers to craft requests that appear legitimate to the application layer while actually instructing the server to access files outside of the intended directory structure. The vulnerability specifically affects how the server handles path resolution when encountering sequences that contain the pipe character combined with dot notation, which can be interpreted by the underlying operating system as legitimate path components rather than malicious traversal attempts.
From an operational impact perspective, this vulnerability presents a severe risk to organizations deploying Son hServer 0.2, as it can potentially expose sensitive system files, configuration data, and user information to unauthorized parties. Attackers could leverage this vulnerability to access system configuration files, database credentials, application source code, and other confidential data that should remain protected. The remote nature of the attack means that adversaries do not require local system access or credentials to exploit this vulnerability, making it particularly dangerous for web applications that are publicly accessible. This type of vulnerability directly violates security principles of least privilege and proper input validation, potentially leading to complete system compromise if sensitive files containing authentication credentials or system configurations are accessible through this vector.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to a patched version of Son hServer or applying the appropriate security patches released by the vendor. Network-level protections such as web application firewalls can help detect and block malicious traversal attempts, though these should be considered temporary measures while permanent fixes are implemented. Input validation should be strengthened to properly sanitize all user-supplied path references, ensuring that any sequence containing traversal attempts is either rejected or properly normalized. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and maps to attack techniques in the MITRE ATT&CK framework under path traversal and privilege escalation categories. Regular security assessments and input validation testing should be conducted to prevent similar vulnerabilities from being introduced in future deployments, with particular attention to how applications handle file system operations and path resolution mechanisms.