File Upload Vulnerability

File Upload Vulnerability
File Upload Vulnerability - Know how to fix File upload vulnerability

Can you suspect that there is a file upload vulnerability on your website? 

Are you afraid that it could be used by hackers to access your site? File Upload Vulnerability one common vulnerability on WordPress CMS.

We wish we could reassure you that there is nothing to think about but the fact is there is a significant problem with a file upload flaw.

If this flaw is discovered on your web by a hacker, they will hijack your site and take complete power. By defacing your sites, removing files, stealing data, and even sending your customers spam emails, they can do significant harm to your web. The top WordPress bugs can be tested here.

In comparison, things will snowball into even broader security problems. When Google discovers the hack, to discourage Google users from viewing it they will blacklist the website automatically. In addition, the domain will be terminated by the web server provider.

But don’t worry, by taking the proper measures to repair and stop file upload bugs on your web, you can keep all this from occurring.

We’ll explain what a file upload vulnerability is in this article and show you the most powerful ways to defend your website against it. You will also hear how WordPress gets compromised by hackers.

What is a File Upload Vulnerability?

For different reasons, several WordPress websites offer visitors the opportunity to upload files. A career registry will encourage a user to upload a resume and credentials, for example. A website for banking will encourage you to upload supporting documents such as name, address, and proof of income. When a file is submitted to your site, the file is checked by WordPress and saved in a special folder called the Uploads folder.

Generally, the records or files submitted by file uploaders are in a format that is unable to perform any commands without any error messages being shown.

The approved formats include png and jpeg for images. Formats include PDF and Docx for papers. And for recordings, it contains extensions for mp3 and mp4 formats. The formats or styles of files cause you to access these files only.

Like we said, these formats are non-executable, which means that the code does not execute any commands on your site, even though there is malicious code in them.

Generally, only non-executable files are accepted by the upload fields on a website. But it will start allowing unlimited file uploads if it malfunctions.

This can be used by hackers to upload executable codes in file formats such as PHP, JavaScript, and exe. You can run commands wreaking havoc on your website with these files. You should verify if SQL injection attacks are stopped.

This is what is known as the vulnerability of a file upload.

You’ll learn how to protect your website against such a weakness in the sections below.

Fortunately, to defend your website from such a vulnerability, there are steps you should take. It’s important, though to understand how this weakness operates. But we’ll take a closer dive at the simple file upload risk in the next section before we address security measures.

What Are The Different Types of File Upload Vulnerability?

We discussed earlier how the weakness of file uploads operates. We’ve said that there are file upload fields on the WordPress website. There are only some kinds of non-executable files that you can upload. But if (due to a vulnerability) the upload field malfunctions, hackers will upload malicious executable files.

Now there are two ways in which a file is accepted by the insecure upload sector.

  1. It will approve a file on the website directly. Hackers will actually upload malicious files in that situation. This is considered the weakness of local file uploads.
  2. Any fields for uploads do not allow direct uploads. They ask you to upload your files to a separate platform, like GDrive, Dropbox, on cloud providers.

Next in the form of a URL, you need to share the venue. The website is going to retrieve the file from the venue. It is an indirect way to upload files that allows malicious files to be posted to a website by an attacker. This is considered the weakness of remote uploads.

The two types of file upload vulnerabilities are local upload vulnerabilities and remote upload vulnerabilities.


The TimThumb vulnerability is one instance of a remote upload vulnerability that springs to mind automatically. It was a common image resizing plugin and a significant number of WordPress websites were affected by the vulnerability. It allowed users to upload images from websites hosting images (like and However, hackers were also able to post malicious data instead of images because of the absence of security controls.

There might be a different file name or different file sizes for such files. But the content of files can be very dangerous.

How Do Hackers Exploit A File Upload Vulnerability?

The hacking process for a website is complicated and scientific. As far as we can, we have simplified things and set out the measures in a manner that is simple for everyone to comprehend.

Hackers are constantly on the lookout for bugs and can hack websites using them.

It is common to find bugs in plugins and templates on a WordPress website. They immediately release an update as creators of plugins and themes hear about such vulnerabilities.

Updates include specifics of the patch, which is how hackers discover that a single plugin or theme has a flaw that can be abused.

What Happens When You Don’t Update Your Site?

Rarely can hackers attack a single website. In order to locate thousands of websites using the insecure plugin, they scour the Internet. As they are ignorant of the value of WordPress notifications, often website owners prefer to delay updates. They keep working on outdated, insecure versions of the plugin.

Let’s say you’re using a plugin on your blog to create a comments section. A file upload flaw was recently found by the creators of this plugin. They issued a patch in an upgrade in order to repair it. You were unable to upgrade the plugin for any reason. In the plugin, the risk persists. Hackers discover that the old edition of the comments plugin is being used on your site. By leveraging the file upload flaw, they upload malicious files to your website (penetration testing). The file includes scripts that can be used to begin performing malicious activities.

Hackers execute commands that allow them to steal sensitive data, such as your website’s database login credentials, until the compromised files are within your website.

Through using the data to log into your website and take full ownership of the site, they will further intensify the hack.

How to Protect Your Website From File Upload Vulnerability?

A file upload vulnerability can have catastrophic technological consequences on your website, as we discussed earlier. However you can patch the flaw and secure your site from hackers if you implement the following steps.

6 major security precautions for the website

1. Install a Security Plugin for WordPress

Getting a WordPress protection plugin built on your web is a smart idea. As we described before, bugs are bound to occur and for whatever reason, hackers would take advantage of this to access the site if you are unable to upgrade the plugin.

We suggest using MalCare, our protection plugin. Amongst other stuff, it comes with a printer and cleaner. To discover secret viruses, the scanner employs sophisticated identification techniques. And the cleaner is automatic, which helps you to use only a few clicks to scrub your website.

The security detector of the plugin will search your website every day and automatically warn you about the hack. In less than a minute, it will also help you clean your website so hackers can destroy your account.


In addition, with a WordPress firewall, the security plugins secure the website.

A WordPress firewall acts like your very own web security superhero that blocks your website from accessing malicious traffic. All incoming traffic from your website is reviewed. It requires positive traffic to reach the site and promptly blocks negative traffic.

This ensures that even though the website has bugs, it will not be abused by hackers because the firewall stops them from accessing the website.


2. Keep Your Website Updated

We mentioned earlier that they patch it and release an improved version when developers find a file upload flaw in their plugin or theme. The latest release would include a protection fix for the web application. The file upload flaw will be resolved on your site until you upgrade to this version.

That said, updates can be a hassle at times. They are constantly accessible and can cause the site to fail or crash often. To upgrade your website securely by using a staging platform, we suggest setting aside time every week.

To set up a staging platform, you can use our plugin, MalCare, and test updates before you instal them on your live site. If you run several websites, the plugin helps you to monitor them all from a single dashboard and upgrade them. This makes it smoother, cheaper, and hassle-free for updates.

File Upload Vulnerability
File Upload Vulnerability

3. Buy Plugins & Themes From Reputed Marketplaces

Vulnerabilities commonly evolve in themes and plugins of low quality. This is why we recommend using only themes and plugins of high quality. Purchasing them from prestigious markets such as Themeforest, CodeCanyon, Evanto, Mojo Marketplace, etc., is a good way to assess the quality of the apps.

Reputed markets for developers have specific policies and security standards to follow. So goods accessible on these sites are developed and well managed with respect.

4. Retire File Uploading Function (If Possible)

You might consider disabling the functionality if you find that the file upload function on your website is not relevant.

This may not be a choice for certain websites, such as recruiting pages. However if your website does not need the file upload feature, we highly recommend that you delete it.

We recommend deactivating and deleting the plugin if you are using a plugin to run the File Uploads function. This would eliminate the risk of a weakness to access files entirely.

5. Change Storage Location of Uploaded Files (Risky)

Anything you upload is saved in the Uploads folder on your WordPress website. The folder is located within the public html directory that holds all your WordPress website’s important data.

It helps hackers to obtain access to the public html archive, i.e. the entire website, as they insert a malicious file into the Upload folder.

It would make it much harder to take ownership of your website if you move the Upload folder outside of this directory.

WARNING: It takes experience to shift the Upload folder, so if you are not acquainted with the inner workings of WordPress, we recommend that you skip this step. We highly advocate taking full website backups before making any improvements, even though you have knowledge of WordPress. The smallest error will cause a split on your website.

That are the 6 vulnerability reduction mechanisms for file uploading. Your site would be safeguarded from file upload bugs by taking these steps. That takes us to the end of preventing vulnerabilities in file sharing on your WordPress account.

In Conclusion

Protecting your WordPress website from bugs in file upload is a step to guarantee that your website is stable and protected from hacking attacks.

Hackers have several more ways to attempt to hack into the web, though. We recommend the following to stop some kind of hack attempts on your website-

  1. Regularly update the WordPress account. Ensure that the newest update of the foundation of WordPress and all extensions and themes built on the website are used.
  2. And now the WordPress site is hardening. Site hardening steps would guarantee that it’s hard for hackers to get into the site.

Taking these precautions so that knowing that your web is secure, you will have peace of mind.