CVE-2017-16194 in picard
Summary
by MITRE
picard is a micro framework. picard is vulnerable to a directory traversal issue, giving an attacker access to the filesystem by placing "../" in the url.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 02/16/2020
The picard micro framework presents a critical directory traversal vulnerability that fundamentally compromises application security boundaries. This vulnerability stems from inadequate input validation within the framework's URL processing mechanism, allowing malicious actors to manipulate resource paths through crafted requests containing "../" sequences. The flaw enables unauthorized access to arbitrary files on the underlying filesystem, potentially exposing sensitive configuration data, source code, user credentials, and other confidential information stored outside the intended application scope. Such vulnerabilities represent a classic example of improper input sanitization that violates fundamental security principles and creates pathways for privilege escalation attacks.
The technical exploitation of this vulnerability occurs when the framework fails to properly sanitize user-supplied URL parameters before resolving file paths. When a request contains directory traversal sequences, the application processes these components without adequate validation, allowing the attacker to navigate upward through the directory structure and access files that should remain restricted. This behavior directly maps to CWE-22, which defines improper limitation of a pathname to a restricted directory vulnerability. The attack vector operates at the application layer where user input directly influences filesystem operations, making it particularly dangerous as it can be exploited through simple HTTP requests without requiring authentication or specialized tools. The vulnerability demonstrates a failure in the principle of least privilege, where the application's file access controls are bypassed through malformed input manipulation.
Operational impact of this vulnerability extends beyond immediate data exposure to encompass complete system compromise potential. An attacker with successful exploitation can access not only application configuration files but also database credentials, private keys, and other sensitive artifacts that may lead to further system infiltration. The vulnerability's accessibility means that any user with knowledge of the framework's URL structure can potentially exploit it, making it particularly dangerous in environments where the framework is deployed without proper network segmentation or additional security controls. This type of vulnerability can facilitate lateral movement within networks, serve as a foothold for more sophisticated attacks, and enable data exfiltration at scale. The impact aligns with ATT&CK technique T1083, which describes discovery of files and directories, and T1566, which covers credential harvesting through social engineering or direct system access.
Mitigation strategies should focus on implementing robust input validation and sanitization at all levels of the application stack. The framework must enforce strict path validation that rejects or normalizes any input containing directory traversal sequences before processing file operations. Implementing a whitelist-based approach for acceptable file paths, combined with proper access controls and secure coding practices, can effectively prevent exploitation. Organizations should also consider implementing web application firewalls that can detect and block suspicious URL patterns, while ensuring proper file system permissions are enforced to limit access to sensitive resources. Regular security testing including penetration testing and code review processes should be implemented to identify similar vulnerabilities in other components of the application stack. The remediation process should include thorough testing to ensure that input sanitization does not introduce new functionality issues while maintaining the application's intended behavior.