CVE-2017-16159 in caolilinode
Summary
by MITRE
caolilinode is a simple file server. caolilinode is vulnerable to a directory traversal issue, giving an attacker access to the filesystem by placing "../" in the url.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 02/16/2020
The vulnerability identified as CVE-2017-16159 affects caolilinode, a simple file server implementation that suffers from a critical directory traversal flaw. This vulnerability stems from inadequate input validation within the application's URL handling mechanism, allowing remote attackers to access arbitrary files on the underlying filesystem through crafted malicious requests. The flaw specifically manifests when the application fails to properly sanitize user-supplied URL parameters, enabling attackers to navigate beyond the intended directory structure by utilizing the "../" sequence commonly known as directory traversal or path traversal attacks.
The technical nature of this vulnerability aligns with CWE-22, which categorizes improper limitation of a pathname to a restricted directory, commonly referred to as path traversal or directory traversal. This weakness occurs when applications fail to properly validate or sanitize input that is used to construct file paths, allowing attackers to manipulate the path to access files outside of the intended directory. The attack vector is particularly straightforward as it requires only URL manipulation to exploit, making it highly accessible to threat actors with basic technical knowledge. When an attacker crafts a URL containing "../" sequences, the application processes these requests without proper validation, resulting in the exposure of files that should remain protected within the server's directory structure.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with unrestricted access to the entire filesystem of the affected server. This access can enable attackers to retrieve sensitive configuration files, database credentials, application source code, and other confidential data that may contain authentication tokens, encryption keys, or other critical information. The vulnerability essentially provides a backdoor into the server's file system, potentially allowing for further exploitation such as privilege escalation, persistence mechanisms, or the deployment of malicious payloads. From an ATT&CK framework perspective, this vulnerability maps to T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachments) as attackers can use the information gathered to craft more sophisticated attacks or gain additional access vectors.
Mitigation strategies for CVE-2017-16159 should focus on implementing proper input validation and sanitization mechanisms within the application's URL processing logic. The most effective approach involves implementing a whitelist-based validation system that only allows specific, expected file paths while rejecting any input containing directory traversal sequences. Additionally, developers should employ secure coding practices that enforce proper path resolution and ensure that all user-supplied input is thoroughly validated before being used to construct file paths. Organizations should also consider implementing web application firewalls that can detect and block directory traversal attempts, while maintaining regular security assessments to identify similar vulnerabilities in other applications. The vulnerability demonstrates the critical importance of input validation and proper access control mechanisms in preventing unauthorized file system access.