CVE-2014-10066 in fancy-server
Summary
by MITRE
Versions less than 0.1.4 of the static file server module fancy-server are vulnerable to directory traversal. An attacker can provide input such as `../` to read files outside of the served directory.
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Analysis
by VulDB Data Team • 02/10/2020
The vulnerability identified as CVE-2014-10066 affects the fancy-server static file server module version 0.1.3 and earlier, representing a critical directory traversal flaw that undermines the fundamental security boundaries of web applications. This issue stems from inadequate input validation and path sanitization within the module's file serving mechanism, creating a pathway for malicious actors to access arbitrary files on the underlying filesystem. The vulnerability operates by exploiting insufficient restrictions on user-supplied path components, particularly the ../ sequence that allows navigation up directory hierarchies. According to CWE-22, this maps directly to improper limitation of a pathname to a restricted directory, a well-documented weakness that enables attackers to bypass intended access controls and retrieve sensitive information from locations outside the designated web root.
The technical exploitation of this vulnerability occurs when the fancy-server module processes file requests without properly validating or sanitizing the requested file paths. When an attacker submits a crafted request containing directory traversal sequences such as ../ or ../../, the module fails to normalize or restrict the path to the intended serving directory, allowing access to files that should remain protected. This flaw essentially creates a backdoor mechanism through which unauthorized file access becomes possible, potentially exposing configuration files, source code, database credentials, or other sensitive data stored on the same server. The impact extends beyond simple information disclosure as attackers can potentially access system files, application logs, or other resources that may contain authentication tokens, private keys, or other critical system information.
Operationally, this vulnerability poses significant risks to organizations deploying the affected fancy-server module, as it can be exploited remotely through web-based interfaces without requiring authentication or specialized privileges. Attackers can systematically explore the filesystem by submitting various traversal sequences to map out directory structures and identify valuable targets for further exploitation. The vulnerability's impact is amplified by its simplicity and the widespread use of static file serving modules in web applications, making it an attractive target for automated scanning tools and opportunistic attackers. According to ATT&CK framework technique T1083, adversaries can leverage such vulnerabilities to discover files and directories, while T1566 focuses on the exploitation of web applications for initial access and privilege escalation. The vulnerability also aligns with the broader category of path traversal attacks that have been consistently ranked among the top security risks in web application security assessments.
Organizations affected by this vulnerability should immediately upgrade to version 0.1.4 or later, which includes proper input validation and path normalization mechanisms to prevent directory traversal attacks. The recommended mitigation strategy involves implementing strict input validation that rejects or sanitizes path components containing directory traversal sequences, combined with proper access control measures that ensure files are served only from designated directories. Additional protective measures include deploying web application firewalls that can detect and block suspicious path traversal patterns, implementing proper logging and monitoring of file access requests, and conducting regular security assessments to identify similar vulnerabilities in other components of the application stack. The fix typically involves implementing a whitelist approach for valid file paths or employing robust path normalization techniques that resolve all relative paths to their canonical form before processing file requests.