Cloudinary Blog

How To Prevent Malware And Detect Infected User Uploads

How To Prevent Malware in Malicious File Upload

Social networking sites allow users to upload images or other types of files that are immediately available to other users via news feeds or notifications. In some cases, attackers can directly spread infected files, but more commonly, they leverage the viral effect and the fact that users are simply unaware that their files are infected through sharing and collaborating with others. As a site owner or application developer, it is your responsibility to protect users and prevent these situations from occurring. Fortunately, Cloudinary makes this easier with its Metascan add-on.

How to prevent malware in malicious file upload

Cloudinary's image management allows you to file upload, along with other files like PDFs, directly from your users’ browsers or mobile applications. While most modern image formats are fairly safe, nothing is guaranteed, and the various other file formats that users use to upload and share may be infected with malicious code. We want to ensure that you and your users are safe so that there's no chance of malware creeping into uploaded files. With Cloudinary's Metascan add-on, you can detect and prevent advanced known and unknown malware and threats by scanning and sanitizing your users' uploaded files.

Webinar
How to Optimize for Page Load Speed

Metascan anti-malware add-on

Brought to you by OPSWAT, Metascan is fully integrated into Cloudinary’s image management and manipulation service. While uploading images to the cloud using Cloudinary’s upload API, you can set the moderation upload API parameter to metascan in order to request to have your uploaded images and other files automatically scanned and removed if malware is detected. It’s also possible to select batches of previously uploaded files to scan using Cloudinary’s API.

With the Metascan add-on, you don't need to install any anti-malware software or build a file scanning pipeline. By simply using Cloudinary's image upload API, or Admin API for previously uploaded images, all of your images can be scanned and moderated accordingly.

Below is a sample code that requests a Metascan scan of a PDF document that is being uploaded to Cloudinary.

Ruby:
Copy to clipboard
Cloudinary::Uploader.upload("local_file.pdf", 
  :moderation => "metascan")
PHP:
Copy to clipboard
\Cloudinary\Uploader::upload("local_file.pdf", 
  array("moderation" => "metascan"));
Python:
Copy to clipboard
cloudinary.uploader.upload("local_file.pdf",
  moderation = "metascan")
Node.js:
Copy to clipboard
cloudinary.uploader.upload("local_file.pdf", 
  function(result) { console.log(result); }, 
  { moderation: "metascan" });
Java:
Copy to clipboard
cloudinary.uploader().upload("local_file.pdf", 
  ObjectUtils.asMap("moderation", "metascan"));

With this request, Metascan performs scans with anti-malware engines (ESet, AVG, ClaimWin and Norman) on images and files that are being uploaded. Scanning is done asynchronously within seconds, meaning there is no impact on user experience. If Metascan detects malware in a file, the file is removed and the CDN cache is invalidated. The original file is stored in secondary storage, which enables you to recover it in case you want to override the Metascan results.

Additionally, you can set up notifications that let you know which files were marked as safe or rejected. You have the option of scanning your user uploaded files with Cloudinary before publishing them, allowing you to share only uploaded content that you know has gotten the green light.

As you can see in the screenshot below, Cloudinary’s online media library allows you to further control this process with multiple lists of pending scan requests, and approved or rejected files, permitting you to override these results if necessary. These can also be performed by the API. For example, if a user reports a file that wasn’t initially found to be malicious, you can mark it as problematic with a single click or API call and remove it or approve it if you think that it was mistakenly marked as containing malware. See our documentation to learn more about the Metascan add-on.

Metascan moderation queue

Final Notes

With all of the cyber threats in the world today, sharing on social networks makes malware distribution fast and dangerous. While most image formats are relatively safe, other formats, such as PDFs, are more risky. At Cloudinary, we are committed to helping you protect your users, website or web application from malware and viruses. Using Cloudinary’s Metascan add-on prevents vulnerabilities and enhances overall site security.

Metascan add-on screenshot

You can try the Metascan add-on for free, just by subscribing to the free add-on plan. If you don't have a Cloudinary account yet, sign up for a free account here.


Further Reading on File Upload

Recent Blog Posts

Transitioning JPEG-Based to JPEG XL-Based Images for Web Platforms

When the JPEG codec was being developed in the late 1980s, no standardized, lossy image-compression formats existed. JPEG became ready at exactly the right time in 1992, when the World Wide Web and digital cameras were about to become a thing. The introduction of HTML’s <img> tag in 1995 ensured the recognition of JPEG as the web format—at least for photographs. During the 1990s, digital cameras replaced analog ones and, given the limited memory capacities of that era, JPEG became the standard format for photography, especially for consumer-grade cameras.

Read more

Amplify Your Jamstack With Video

By Alex Patterson
Amplify Your Jamstack With Cloudinary Video

As defined by Amazon Web Services (AWS), Amplify is a set of products and tools with which mobile and front-end web developers can build and deploy AWS-powered, secure, and scalable full-stack apps. Also, you can efficiently configure their back ends, connect them to your app with just a few lines of code, and deploy static web apps in only three steps. Historically, because of their performance issues, managing images and videos is a daunting challenge for developers. Even though you can easily load media to an S3 bucket with AWS Amplify, transforming, compressing, and responsively delivering them is labor intensive and time consuming.

Read more
Cloudinary Helps Move James Hardie’s Experience Online

While COVID has affected most businesses, it has been particularly hard on those that sell products for the physical ‘brick and mortar’ world. One company that literally fits that bill is our Australian customer James Hardie, the largest global manufacturer of fibre cement products used in both domestic and commercial construction. These are materials that its buyers ideally want to see up close, in detail. When customers have questions, they expect personal service.

Read more
How to Build an Enhanced Gravatar Service, Part 2

Part 1 of this post defines the capabilities of an enhanced Gravatar service, which I named Clavatar, and describes the following initial steps for building it:

This post, part 2 of the series, explains how to make Clavatar work like Gravatar and to develop Clavatar’s capabilities of enabling requests for various versions of the images related to user accounts.

Read more