CVE-2017-10665 in phpGrid
Summary
by MITRE
Directory traversal vulnerability in ajaxfileupload.php Kayson Group Ltd. phpGrid before 7.2.5 allows remote attackers to execute arbitrary code by uploading a crafted file with a .. (dot dot) in the file name.
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Analysis
by VulDB Data Team • 11/08/2019
The vulnerability identified as CVE-2017-10665 represents a critical directory traversal flaw within the ajaxfileupload.php component of phpGrid versions prior to 7.2.5, developed by Kayson Group Ltd. This directory traversal vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly restrict file upload operations. The flaw specifically manifests when the application processes file names containing directory traversal sequences such as .. (dot dot) characters, which can manipulate the intended file storage location. The vulnerability is classified under CWE-22 as a directory traversal attack, where attackers can exploit insufficient restrictions on file paths to access or manipulate files outside the intended directory structure. This weakness is particularly dangerous in web applications where file upload functionality is exposed to untrusted users without proper security controls.
The technical exploitation of this vulnerability occurs through the manipulation of file names during the upload process, specifically by incorporating .. sequences that can traverse up the directory tree. When the application processes an uploaded file with such a crafted filename, it fails to properly sanitize or validate the path components, allowing the system to interpret the .. sequences as legitimate directory navigation commands. Attackers can leverage this flaw to upload malicious files to arbitrary locations on the server filesystem, potentially bypassing security restrictions that should prevent execution of code in sensitive directories. The vulnerability enables remote code execution capabilities when attackers upload files with executable extensions such as .php, .asp, or .jsp, which can then be executed by the web server. This represents a fundamental failure in input validation and path handling within the file upload mechanism, creating a pathway for attackers to gain unauthorized access to the system's file structure.
The operational impact of CVE-2017-10665 extends beyond simple file access violations to encompass complete system compromise when attackers successfully exploit the vulnerability. Remote attackers can leverage this weakness to upload backdoor files, web shells, or other malicious payloads that persist on the server and provide ongoing access to the compromised system. The vulnerability affects the integrity and confidentiality of the web application and underlying server, as attackers can potentially read sensitive configuration files, database credentials, or other protected resources. This flaw can be particularly devastating in environments where the web application has elevated privileges or access to sensitive data stores. The vulnerability also aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where adversaries can execute code through uploaded files that bypass normal security controls. The attack surface is broad, as the vulnerability exists in the file upload functionality that is commonly exposed to external users, making it a prime target for automated exploitation attempts.
Mitigation strategies for CVE-2017-10665 must address both the immediate vulnerability and implement comprehensive security controls to prevent similar issues in the future. The most effective immediate solution involves upgrading to phpGrid version 7.2.5 or later, which contains the necessary patches to prevent directory traversal attacks. Organizations should also implement robust file name validation and sanitization processes that strip or encode potentially dangerous characters including .. sequences, spaces, and other path traversal indicators. Input validation should occur at multiple levels including client-side and server-side, with server-side validation being the primary defense mechanism. Additional security measures include implementing strict file type validation, using random or obfuscated filenames during upload processes, and ensuring proper file permissions that prevent execution of uploaded files in web-accessible directories. The implementation of Content Security Policy (CSP) headers and proper web server configuration can further limit the impact of successful exploitation attempts. Organizations should also establish regular security auditing practices to identify and remediate similar vulnerabilities in other components of their web applications, as directory traversal issues are common across many web frameworks and applications. The vulnerability serves as a reminder of the critical importance of proper input validation and the principle of least privilege in web application security design.