Allowing users to upload files through your online forms can be incredibly useful for job applications, support tickets, or document submissions. However, it can also be a risky business… Improper handling of file uploads could invite malware infections, unauthorized access, and server vulnerabilities without you realizing it.
So, do you want to protect yourself before you wreck yourself? Keep reading to learn my top tips for file upload security with your online forms.
File Upload Security: Top Tips for Online Forms
1. Restrict Certain File Types
Not all file types should be accepted on your forms! Restricting uploads to only necessary and safe formats (like PDF, JPG, and PNG) minimizes security risks.
Fortunately, you can restrict certain file types in WPForms
Our flexible form builder lets you specify permitted file extensions in the File Upload field settings.
To further customize accepted file types, you can use the File Upload Types by WPForms plugin to enable additional safe file formats.
Avoiding file types like .exe, .php, or .js helps prevent potentially malicious files from being executed on your server. Additionally, blocking uncommon formats reduces the risk of accidental security loopholes.
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2. Set File Size Limits
Large file uploads can slow down your website and may indicate an attempt to exploit server resources. So keeping file sizes within reasonable limits reduces the risk of attacks.
Once again in the File Upload field settings, you can define your maximum file sizes.
A good rule of thumb is to set a file size limit that accommodates your needs without allowing excessive uploads. For example, image uploads for a contact form might be capped at 2MB, while document submissions for a job application could allow up to 5MB.
For additional server-level restrictions, adjust the php.ini file or use your hosting provider’s settings to enforce limits.
3. Scan Uploaded Files for Malware
Cybercriminals can disguise malicious files as legitimate uploads.
As in, a .jpg image might actually contain embedded malicious code. Without scanning, these files could be executed unknowingly and lead to a data breach or compromised website.
To protect your site:
- Use a WordPress security plugin with malware-scanning capabilities.
- Store uploaded files in a quarantine folder and scan them before making them accessible.
- Consider integrating third-party services for automated scanning of uploaded files.
Some hosting providers also offer built-in malware scanning tools, which can be scheduled to run periodically and catch potential threats before they become a problem.
Taking these measures is like having your own security guard to ward off those pesky criminals.
4. Secure File Storage and Access
Where and how you store uploaded files matters. Instead of keeping sensitive files in your public wp-content folder, opt for more secure storage solutions.
To utilize offsite storage options, WPForms allows you to integrate with:
- Dropbox: Automatically send uploaded files to Dropbox for secure storage.
- Google Drive (via Zapier): Use Zapier to move files from WPForms to Google Drive, reducing storage risks on your WordPress server.
When setting up your file storage, be sure to configure access permissions properly to prevent unauthorized access. More on that, next.
5. Grant Access & Require Passwords
Not all users should be trusted with the content uploaded on your forms. So, you should consider taking a few steps to limit this access.
This way, unauthorized people are prevented from accessing sensitive information uploaded through your forms.
To adjust these settings, navigate to the Advanced tab and click Enable File Access Restrictions.
When toggling this option, a dropdown menu appears below. Here, you can select which users have file access. Select logged-in users to make sure only these folks can view the uploaded files.
Another choice you have when enabling restrictions is to add password protection. If you want to require a password for a user to access an uploaded file, toggle the Password Protection option.
Doing so will prompt you to enter and confirm the password that users will need to use.
Not a logged-in user? No file for you! Don’t have the password? Sorry, not sorry!
Taking a couple of simple, extra measures on your file upload forms can work wonders for protecting your site.
Also Read: How to Assign User Roles Conditionally in WordPress
6. Enable HTTPS for Secure File Transfers
To protect file uploads from being intercepted by attackers, make sure your site uses SSL/HTTPS encryption. Many hosting providers offer free SSL certificates, or you can set it up with a provider for added security.
When HTTPS is enabled, all file uploads and downloads are encrypted in transit. If your site is still using HTTP, search engines may flag it as “Not Secure,” and your users may not trust it.
To check if your site has SSL enabled, look for the padlock symbol in your browser’s address bar. If you don’t see it, you may need to install an SSL certificate through your hosting provider.
7. Regularly Audit and Delete Unnecessary Files
Leaving old, unused uploaded files on your server can increase security risks.
Instead, you should regularly:
- Audit stored files for any security threats.
- Delete outdated or unnecessary uploads to keep your site clean and secure.
File uploads are a powerful feature, but you do want to protect your forms with proper security measures.
With WPForms’ built-in security features and integrations like Dropbox and Google Drive, you can take ownership of file management without sacrificing safety. Implement these best practices today to keep your site secure!
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FAQ
Need the highlights? Browse our frequently asked questions about file upload security:
How can I prevent users from uploading potentially harmful files?
You can restrict file uploads to safe formats (like PDF, JPG, and PNG) using WPForms’ File Upload field settings. For more control, use the File Upload Types by WPForms plugin to customize allowed file extensions.
How do I prevent unauthorized users from accessing uploaded files?
Limit file access by adjusting user roles and permissions in WordPress. Use WPForms’ file access settings to restrict who can view or download uploaded files from the backend.
Should I store uploaded files on my WordPress server?
While you can store files on your WordPress server, offsite storage solutions like Dropbox (WPForms Addon) or Google Drive (via Zapier) provide better security and reduce server risks.
Next, Monitor and Analyze Spam
Another critical aspect of file upload security is monitoring for spammy or unwanted submissions. Bots and spammers often attempt to flood upload forms with junk files. Want to use it to your advantage? Learn how to monitor and analyze spam in our full guide.
Ready to build your form? Get started today with the easiest WordPress form builder plugin. WPForms Pro includes lots of free templates and offers a 14-day money-back guarantee.
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