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Can a virus upload files?
Malicious files including Windows viruses, Unix shell scripts and Excel files may be uploaded if there are unrestricted file uploads. A server administrator or webmaster might discover these files, then open them to determine what they are — executing the code and allowing malware onto your server.
How can you ensure that an uploaded file will not compromise your web server?
Protection
- Segregate Your Uploads. File uploads are generally intended to be inert.
- Ensure Upload Files Cannot Be Executed.
- Rename Files on Upload.
- Validate File Formats and Extensions.
- Validate the Content-Type Header.
- Use a Virus Scanner.
- Check File Sizes.
- Sanitize Filenames.
Originally Published February 17, 2014. Video files are not typically thought of as potentially malicious or infected file types, but it is possible for malware to be embedded in or disguised as a video file.
What is the definition of malicious file upload?
Malicious File Upload Description: If applications having file upload feature do not check for permissible then those applications are having malicious file upload vulnerability. The server or computer system may get affected with virus or other malicious software if run after upload.
What happens if I upload a virus to my computer?
The server or computer system may get affected with virus or other malicious software if run after upload. The application may execute malicious code if the uploaded file has executable code in it and it is used to run as part of a program. Implement file size checker to avoid Denial of Service by trying to upload too large files.
How is a remote file upload vulnerability created?
A remote file upload vulnerability is a vulnerability where an application uses user input to fetch a remote file from a site on the Internet and store it locally. This file is then executed by an attacker. Lets look at each of these vulnerabilities in some detail, how they are created and how to avoid them.
How to protect your website from malicious file uploads?
Instead, the uploaded file should be renamed according to a predetermined convention. While these techniques cannot guarantee a website will never be attacked from a malicious file upload, they will go a long way toward protecting the website while still providing users with the benefits of uploading files when needed.