CVE-2010-4181 in Web Server
Summary
by MITRE
Directory traversal vulnerability in Yaws 1.89 allows remote attackers to read arbitrary files via ..\ (dot dot backslash) and other sequences.
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Analysis
by VulDB Data Team • 09/28/2021
The vulnerability identified as CVE-2010-4181 represents a critical directory traversal flaw in Yaws version 1.89, a high-performance web server written in erlang. This weakness enables remote attackers to access arbitrary files on the server by exploiting improper input validation mechanisms within the file path handling routines. The vulnerability specifically manifests when the web server fails to adequately sanitize user-supplied input that contains directory traversal sequences such as ..\ or other malicious path constructs that attempt to navigate outside the intended directory structure.
The technical implementation of this flaw stems from insufficient validation of file path parameters in Yaws 1.89's web serving components. When user requests contain directory traversal sequences, the server processes these inputs without proper sanitization or canonicalization, allowing attackers to manipulate file access paths. The ..\ sequence specifically exploits Windows-style path traversal where backslashes are interpreted as directory navigation commands, enabling access to files outside the web root directory. This vulnerability falls under the CWE-22 category of Improper Limitation of a Pathname to a Restricted Directory, which is a fundamental security weakness in file system access control mechanisms.
The operational impact of this vulnerability is severe as it provides attackers with the ability to read arbitrary files from the server filesystem, potentially exposing sensitive information such as configuration files, database credentials, application source code, and other confidential data. Remote exploitation means that attackers do not require local access or authentication to leverage this vulnerability, making it particularly dangerous in publicly accessible web environments. The attack surface extends to any file accessible by the web server process, including system configuration files, user data, and application resources that should remain protected from unauthorized access.
Mitigation strategies for this vulnerability include immediate patching of Yaws to versions that properly implement input validation and path canonicalization. System administrators should implement proper input sanitization at all levels of the web application stack, ensuring that all user-supplied file path parameters are validated against a whitelist of acceptable characters and patterns. Network segmentation and access controls should be enforced to limit exposure, while regular security audits should verify that path traversal vulnerabilities are properly addressed. The ATT&CK framework categorizes this type of vulnerability under T1083 - File and Directory Discovery, which represents a common reconnaissance technique used by attackers to map file system structures. Organizations should also implement web application firewalls and input validation mechanisms to detect and block malicious path traversal attempts before they can be processed by the web server.