CVE-2014-3855 in Pyplate
Summary
by MITRE
Directory traversal vulnerability in download.py in Pyplate 0.08 allows remote attackers to read arbitrary files via a .. (dot dot) in the filename parameter.
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Analysis
by VulDB Data Team • 03/11/2019
The vulnerability identified as CVE-2014-3855 represents a critical directory traversal flaw within the Pyplate 0.08 web application framework. This issue resides in the download.py component which handles file download operations, creating a pathway for malicious actors to access arbitrary files on the server filesystem. The vulnerability stems from inadequate input validation and sanitization of the filename parameter, which fails to properly filter or restrict directory navigation sequences. Attackers can exploit this weakness by crafting malicious requests containing .. (dot dot) sequences in the filename parameter, effectively bypassing intended file access controls and gaining unauthorized access to sensitive system files. The flaw operates at the application layer and can be leveraged by remote attackers without requiring authentication or privileged access to the system. This vulnerability directly maps to CWE-22, which defines improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The attack vector follows the pattern described in MITRE ATT&CK technique T1083, where adversaries attempt to gather information about the file system to identify sensitive data and system resources.
The technical implementation of this vulnerability demonstrates a classic lack of proper input validation mechanisms within the Pyplate framework. When the download.py script processes user-supplied filename parameters, it does not adequately sanitize or validate the input to prevent directory traversal sequences. This allows attackers to manipulate the file path resolution mechanism by injecting sequences such as ../ or ..\ that navigate up the directory tree. The impact extends beyond simple file access, as successful exploitation can lead to disclosure of configuration files, source code, database credentials, and other sensitive information stored on the same server. The vulnerability is particularly dangerous because it can be exploited through simple HTTP requests, making it easily accessible to attackers with basic web exploitation knowledge. The flaw essentially allows an attacker to traverse the file system hierarchy and access files that should normally be restricted to authorized users only.
The operational impact of CVE-2014-3855 is significant for organizations utilizing Pyplate 0.08, as it provides a straightforward method for unauthorized information disclosure. Attackers can leverage this vulnerability to extract sensitive data including but not limited to application configuration files, database connection strings, user credentials, and potentially system-level files that contain critical operational information. The vulnerability's remote exploitability means that attackers do not need physical access to the system or network privileges to carry out successful attacks. This makes the vulnerability particularly attractive to automated exploitation tools and malicious actors seeking to compromise web applications. The affected environment can include any system running Pyplate 0.08 that exposes the download functionality to untrusted users, potentially affecting web servers, application servers, and other systems where the framework is deployed. The vulnerability can also serve as a stepping stone for further attacks, as the leaked information can be used to identify other system weaknesses and plan more sophisticated exploitation attempts.
Mitigation strategies for CVE-2014-3855 should focus on implementing proper input validation and sanitization mechanisms within the Pyplate framework. The most effective immediate solution involves modifying the download.py script to validate and sanitize all filename parameters, rejecting any input containing directory traversal sequences such as .. or \. Organizations should implement absolute path validation to ensure that file operations occur only within predetermined directories and reject any attempts to navigate outside these boundaries. The implementation should include proper path normalization and canonicalization of file paths to prevent malicious sequences from being interpreted correctly. Security patches should be applied to upgrade to Pyplate versions that address this vulnerability, and organizations should consider implementing web application firewalls to detect and block suspicious requests containing directory traversal patterns. Additionally, regular security assessments and input validation reviews should be conducted to identify similar vulnerabilities in other components of the application stack. The remediation process should also include restricting file access permissions and implementing principle of least privilege for file system operations to minimize the potential impact of any remaining vulnerabilities.