File Upload Vulnerabilities

File upload vulnerabilities are a type of vulnerability that allows an attacker to upload a malicious file to a web server. This can lead to a variety of attacks, including Remote Code Execution (RCE), Cross-Site Scripting (XSS), and Denial of Service (DoS).

Common Types of File Upload Vulnerabilities

• Unrestricted File Upload: The application allows an attacker to upload a file with any extension.
• Weak File Type Validation: The application only checks the file extension to validate the file type.
• Path Traversal: An attacker can use a path traversal vulnerability to upload a file to an arbitrary location on the server.

Prevention Methods

• Use a Whitelist of Allowed File Extensions: A whitelist of allowed file extensions will ensure that only safe files can be uploaded.
• Validate the File Type on the Server-Side: The file type should be validated on the server-side, not just on the client-side.
• Store Uploaded Files in a Secure Location: Uploaded files should be stored in a secure location that is not directly accessible from the internet.
• Rename Uploaded Files: Uploaded files should be renamed to a random and unpredictable value.