CVE-2018-9207 in jQuery Upload File
Summary
by MITRE
Arbitrary file upload in jQuery Upload File <= 4.0.2
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Analysis
by VulDB Data Team • 04/14/2020
The vulnerability identified as CVE-2018-9207 represents a critical security flaw in the jQuery Upload File plugin version 4.0.2 and earlier, which falls under the category of insecure file upload functionality. This issue enables attackers to bypass file type validation mechanisms and upload malicious files to web servers, potentially leading to remote code execution or other severe security consequences. The vulnerability stems from insufficient input validation and sanitization within the file upload process, allowing unauthorized file uploads without proper authorization checks.
The technical implementation of this vulnerability occurs through the plugin's file upload handler which fails to properly validate file extensions, MIME types, or file contents before storing uploaded files on the server. Attackers can exploit this weakness by crafting malicious files with deceptive extensions or by directly manipulating the upload process to bypass client-side validation. The flaw essentially creates a path traversal vulnerability where uploaded files can be stored in directories accessible via web requests, potentially allowing attackers to execute malicious code through uploaded scripts or web shells. This type of vulnerability directly maps to CWE-434, which describes insecure file upload scenarios where applications fail to properly validate or restrict uploaded files.
The operational impact of CVE-2018-9207 extends beyond simple unauthorized file uploads, as it can lead to complete system compromise when attackers successfully upload malicious payloads. Organizations using vulnerable versions of jQuery Upload File may face data breaches, service disruption, and potential lateral movement within their network infrastructure. The vulnerability is particularly dangerous because it can be exploited by attackers with minimal privileges, making it an attractive target for both external attackers and insider threats. This weakness creates opportunities for attackers to establish persistent access through web shells, exfiltrate sensitive data, or use the compromised server as a launch point for further attacks within the network environment.
Mitigation strategies for this vulnerability require immediate patching of the jQuery Upload File plugin to versions that properly validate file uploads and implement strict file type restrictions. Security measures should include implementing comprehensive file validation on both client and server sides, enforcing strict file extension checks, and ensuring uploaded files are stored outside the web root directory. Organizations should also implement proper access controls and monitoring for file upload activities, along with regular security assessments to identify similar vulnerabilities in other components. The ATT&CK framework categorizes this vulnerability under T1190 for exploit public-facing application and T1059 for command and scripting interpreter, highlighting the potential for both initial compromise and post-exploitation activities through this weakness. Additional defensive measures include implementing web application firewalls, conducting regular security code reviews, and establishing secure coding practices that prevent similar insecure file upload scenarios in custom applications.